[Dep] Update fmtlib to 10.0.0

15 files changed, 6245 insertions, 4899 deletions

diff --git a/contrib/DEPENDENCY_INFO.md b/contrib/DEPENDENCY_INFO.md
index 745b60d76..4b3f8cb1c 100644
--- a/contrib/DEPENDENCY_INFO.md
+++ b/contrib/DEPENDENCY_INFO.md
@@ -32,7 +32,7 @@
 | fastutf8               | ?       | MIT                 | YES     | many changes       |
 | expected               | v1.0    | Public Domain / CC0 | NO      |                    |
 | frozen                 | 1.0.1   | Apache 2            | NO      |                    |
-| fmt                    | 8.1.1   | MIT                 | NO      |                    |
+| fmt                    | 10.0.0  | MIT                 | NO      |                    |
 | doctest                | 2.4.6   | MIT                 | NO      |                    |
 | function2              | 4.1.0   | Boost               | NO      |                    |
 | ankerl/svector         | 1.0.2   | MIT                 | NO      |                    |
diff --git a/contrib/fmt/include/fmt/args.h b/contrib/fmt/include/fmt/args.h
new file mode 100644
index 000000000..a3966d140
--- /dev/null
+++ b/contrib/fmt/include/fmt/args.h
@@ -0,0 +1,234 @@
+// Formatting library for C++ - dynamic format arguments
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_ARGS_H_
+#define FMT_ARGS_H_
+
+#include <functional>  // std::reference_wrapper
+#include <memory>      // std::unique_ptr
+#include <vector>
+
+#include "core.h"
+
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+
+template <typename T> struct is_reference_wrapper : std::false_type {};
+template <typename T>
+struct is_reference_wrapper<std::reference_wrapper<T>> : std::true_type {};
+
+template <typename T> const T& unwrap(const T& v) { return v; }
+template <typename T> const T& unwrap(const std::reference_wrapper<T>& v) {
+  return static_cast<const T&>(v);
+}
+
+class dynamic_arg_list {
+  // Workaround for clang's -Wweak-vtables. Unlike for regular classes, for
+  // templates it doesn't complain about inability to deduce single translation
+  // unit for placing vtable. So storage_node_base is made a fake template.
+  template <typename = void> struct node {
+    virtual ~node() = default;
+    std::unique_ptr<node<>> next;
+  };
+
+  template <typename T> struct typed_node : node<> {
+    T value;
+
+    template <typename Arg>
+    FMT_CONSTEXPR typed_node(const Arg& arg) : value(arg) {}
+
+    template <typename Char>
+    FMT_CONSTEXPR typed_node(const basic_string_view<Char>& arg)
+        : value(arg.data(), arg.size()) {}
+  };
+
+  std::unique_ptr<node<>> head_;
+
+ public:
+  template <typename T, typename Arg> const T& push(const Arg& arg) {
+    auto new_node = std::unique_ptr<typed_node<T>>(new typed_node<T>(arg));
+    auto& value = new_node->value;
+    new_node->next = std::move(head_);
+    head_ = std::move(new_node);
+    return value;
+  }
+};
+}  // namespace detail
+
+/**
+  \rst
+  A dynamic version of `fmt::format_arg_store`.
+  It's equipped with a storage to potentially temporary objects which lifetimes
+  could be shorter than the format arguments object.
+
+  It can be implicitly converted into `~fmt::basic_format_args` for passing
+  into type-erased formatting functions such as `~fmt::vformat`.
+  \endrst
+ */
+template <typename Context>
+class dynamic_format_arg_store
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+    // Workaround a GCC template argument substitution bug.
+    : public basic_format_args<Context>
+#endif
+{
+ private:
+  using char_type = typename Context::char_type;
+
+  template <typename T> struct need_copy {
+    static constexpr detail::type mapped_type =
+        detail::mapped_type_constant<T, Context>::value;
+
+    enum {
+      value = !(detail::is_reference_wrapper<T>::value ||
+                std::is_same<T, basic_string_view<char_type>>::value ||
+                std::is_same<T, detail::std_string_view<char_type>>::value ||
+                (mapped_type != detail::type::cstring_type &&
+                 mapped_type != detail::type::string_type &&
+                 mapped_type != detail::type::custom_type))
+    };
+  };
+
+  template <typename T>
+  using stored_type = conditional_t<
+      std::is_convertible<T, std::basic_string<char_type>>::value &&
+          !detail::is_reference_wrapper<T>::value,
+      std::basic_string<char_type>, T>;
+
+  // Storage of basic_format_arg must be contiguous.
+  std::vector<basic_format_arg<Context>> data_;
+  std::vector<detail::named_arg_info<char_type>> named_info_;
+
+  // Storage of arguments not fitting into basic_format_arg must grow
+  // without relocation because items in data_ refer to it.
+  detail::dynamic_arg_list dynamic_args_;
+
+  friend class basic_format_args<Context>;
+
+  unsigned long long get_types() const {
+    return detail::is_unpacked_bit | data_.size() |
+           (named_info_.empty()
+                ? 0ULL
+                : static_cast<unsigned long long>(detail::has_named_args_bit));
+  }
+
+  const basic_format_arg<Context>* data() const {
+    return named_info_.empty() ? data_.data() : data_.data() + 1;
+  }
+
+  template <typename T> void emplace_arg(const T& arg) {
+    data_.emplace_back(detail::make_arg<Context>(arg));
+  }
+
+  template <typename T>
+  void emplace_arg(const detail::named_arg<char_type, T>& arg) {
+    if (named_info_.empty()) {
+      constexpr const detail::named_arg_info<char_type>* zero_ptr{nullptr};
+      data_.insert(data_.begin(), {zero_ptr, 0});
+    }
+    data_.emplace_back(detail::make_arg<Context>(detail::unwrap(arg.value)));
+    auto pop_one = [](std::vector<basic_format_arg<Context>>* data) {
+      data->pop_back();
+    };
+    std::unique_ptr<std::vector<basic_format_arg<Context>>, decltype(pop_one)>
+        guard{&data_, pop_one};
+    named_info_.push_back({arg.name, static_cast<int>(data_.size() - 2u)});
+    data_[0].value_.named_args = {named_info_.data(), named_info_.size()};
+    guard.release();
+  }
+
+ public:
+  constexpr dynamic_format_arg_store() = default;
+
+  /**
+    \rst
+    Adds an argument into the dynamic store for later passing to a formatting
+    function.
+
+    Note that custom types and string types (but not string views) are copied
+    into the store dynamically allocating memory if necessary.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      store.push_back(42);
+      store.push_back("abc");
+      store.push_back(1.5f);
+      std::string result = fmt::vformat("{} and {} and {}", store);
+    \endrst
+  */
+  template <typename T> void push_back(const T& arg) {
+    if (detail::const_check(need_copy<T>::value))
+      emplace_arg(dynamic_args_.push<stored_type<T>>(arg));
+    else
+      emplace_arg(detail::unwrap(arg));
+  }
+
+  /**
+    \rst
+    Adds a reference to the argument into the dynamic store for later passing to
+    a formatting function.
+
+    **Example**::
+
+      fmt::dynamic_format_arg_store<fmt::format_context> store;
+      char band[] = "Rolling Stones";
+      store.push_back(std::cref(band));
+      band[9] = 'c'; // Changing str affects the output.
+      std::string result = fmt::vformat("{}", store);
+      // result == "Rolling Scones"
+    \endrst
+  */
+  template <typename T> void push_back(std::reference_wrapper<T> arg) {
+    static_assert(
+        need_copy<T>::value,
+        "objects of built-in types and string views are always copied");
+    emplace_arg(arg.get());
+  }
+
+  /**
+    Adds named argument into the dynamic store for later passing to a formatting
+    function. ``std::reference_wrapper`` is supported to avoid copying of the
+    argument. The name is always copied into the store.
+  */
+  template <typename T>
+  void push_back(const detail::named_arg<char_type, T>& arg) {
+    const char_type* arg_name =
+        dynamic_args_.push<std::basic_string<char_type>>(arg.name).c_str();
+    if (detail::const_check(need_copy<T>::value)) {
+      emplace_arg(
+          fmt::arg(arg_name, dynamic_args_.push<stored_type<T>>(arg.value)));
+    } else {
+      emplace_arg(fmt::arg(arg_name, arg.value));
+    }
+  }
+
+  /** Erase all elements from the store */
+  void clear() {
+    data_.clear();
+    named_info_.clear();
+    dynamic_args_ = detail::dynamic_arg_list();
+  }
+
+  /**
+    \rst
+    Reserves space to store at least *new_cap* arguments including
+    *new_cap_named* named arguments.
+    \endrst
+  */
+  void reserve(size_t new_cap, size_t new_cap_named) {
+    FMT_ASSERT(new_cap >= new_cap_named,
+               "Set of arguments includes set of named arguments");
+    data_.reserve(new_cap);
+    named_info_.reserve(new_cap_named);
+  }
+};
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_ARGS_H_
diff --git a/contrib/fmt/include/fmt/chrono.h b/contrib/fmt/include/fmt/chrono.h
index 682efd8d2..55e8a5067 100644
--- a/contrib/fmt/include/fmt/chrono.h
+++ b/contrib/fmt/include/fmt/chrono.h
@@ -10,6 +10,8 @@
 
 #include <algorithm>
 #include <chrono>
+#include <cmath>    // std::isfinite
+#include <cstring>  // std::memcpy
 #include <ctime>
 #include <iterator>
 #include <locale>
@@ -20,6 +22,24 @@
 
 FMT_BEGIN_NAMESPACE
 
+// Check if std::chrono::local_t is available.
+#ifndef FMT_USE_LOCAL_TIME
+#  ifdef __cpp_lib_chrono
+#    define FMT_USE_LOCAL_TIME (__cpp_lib_chrono >= 201907L)
+#  else
+#    define FMT_USE_LOCAL_TIME 0
+#  endif
+#endif
+
+// Check if std::chrono::utc_timestamp is available.
+#ifndef FMT_USE_UTC_TIME
+#  ifdef __cpp_lib_chrono
+#    define FMT_USE_UTC_TIME (__cpp_lib_chrono >= 201907L)
+#  else
+#    define FMT_USE_UTC_TIME 0
+#  endif
+#endif
+
 // Enable tzset.
 #ifndef FMT_USE_TZSET
 // UWP doesn't provide _tzset.
@@ -201,7 +221,8 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
     }
     const auto min1 =
         (std::numeric_limits<IntermediateRep>::min)() / Factor::num;
-    if (count < min1) {
+    if (detail::const_check(!std::is_unsigned<IntermediateRep>::value) &&
+        count < min1) {
       ec = 1;
       return {};
     }
@@ -321,14 +342,13 @@ constexpr const size_t codecvt_result<CodeUnit>::max_size;
 template <typename CodeUnit>
 void write_codecvt(codecvt_result<CodeUnit>& out, string_view in_buf,
                    const std::locale& loc) {
-  using codecvt = std::codecvt<CodeUnit, char, std::mbstate_t>;
 #if FMT_CLANG_VERSION
 #  pragma clang diagnostic push
 #  pragma clang diagnostic ignored "-Wdeprecated"
-  auto& f = std::use_facet<codecvt>(loc);
+  auto& f = std::use_facet<std::codecvt<CodeUnit, char, std::mbstate_t>>(loc);
 #  pragma clang diagnostic pop
 #else
-  auto& f = std::use_facet<codecvt>(loc);
+  auto& f = std::use_facet<std::codecvt<CodeUnit, char, std::mbstate_t>>(loc);
 #endif
   auto mb = std::mbstate_t();
   const char* from_next = nullptr;
@@ -344,7 +364,7 @@ auto write_encoded_tm_str(OutputIt out, string_view in, const std::locale& loc)
   if (detail::is_utf8() && loc != get_classic_locale()) {
     // char16_t and char32_t codecvts are broken in MSVC (linkage errors) and
     // gcc-4.
-#if FMT_MSC_VER != 0 || \
+#if FMT_MSC_VERSION != 0 || \
     (defined(__GLIBCXX__) && !defined(_GLIBCXX_USE_DUAL_ABI))
     // The _GLIBCXX_USE_DUAL_ABI macro is always defined in libstdc++ from gcc-5
     // and newer.
@@ -357,37 +377,11 @@ auto write_encoded_tm_str(OutputIt out, string_view in, const std::locale& loc)
     unit_t unit;
     write_codecvt(unit, in, loc);
     // In UTF-8 is used one to four one-byte code units.
-    auto&& buf = basic_memory_buffer<char, unit_t::max_size * 4>();
-    for (code_unit* p = unit.buf; p != unit.end; ++p) {
-      uint32_t c = static_cast<uint32_t>(*p);
-      if (sizeof(code_unit) == 2 && c >= 0xd800 && c <= 0xdfff) {
-        // surrogate pair
-        ++p;
-        if (p == unit.end || (c & 0xfc00) != 0xd800 ||
-            (*p & 0xfc00) != 0xdc00) {
-          FMT_THROW(format_error("failed to format time"));
-        }
-        c = (c << 10) + static_cast<uint32_t>(*p) - 0x35fdc00;
-      }
-      if (c < 0x80) {
-        buf.push_back(static_cast<char>(c));
-      } else if (c < 0x800) {
-        buf.push_back(static_cast<char>(0xc0 | (c >> 6)));
-        buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
-      } else if ((c >= 0x800 && c <= 0xd7ff) || (c >= 0xe000 && c <= 0xffff)) {
-        buf.push_back(static_cast<char>(0xe0 | (c >> 12)));
-        buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
-        buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
-      } else if (c >= 0x10000 && c <= 0x10ffff) {
-        buf.push_back(static_cast<char>(0xf0 | (c >> 18)));
-        buf.push_back(static_cast<char>(0x80 | ((c & 0x3ffff) >> 12)));
-        buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
-        buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
-      } else {
-        FMT_THROW(format_error("failed to format time"));
-      }
-    }
-    return copy_str<char>(buf.data(), buf.data() + buf.size(), out);
+    unicode_to_utf8<code_unit, basic_memory_buffer<char, unit_t::max_size * 4>>
+        u;
+    if (!u.convert({unit.buf, to_unsigned(unit.end - unit.buf)}))
+      FMT_THROW(format_error("failed to format time"));
+    return copy_str<char>(u.c_str(), u.c_str() + u.size(), out);
   }
   return copy_str<char>(in.data(), in.data() + in.size(), out);
 }
@@ -426,7 +420,7 @@ auto write(OutputIt out, const std::tm& time, const std::locale& loc,
            char format, char modifier = 0) -> OutputIt {
   auto&& buf = get_buffer<Char>(out);
   do_write<Char>(buf, time, loc, format, modifier);
-  return buf.out();
+  return get_iterator(buf, out);
 }
 
 template <typename Char, typename OutputIt,
@@ -440,7 +434,7 @@ auto write(OutputIt out, const std::tm& time, const std::locale& loc,
 
 }  // namespace detail
 
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 /**
   Converts given time since epoch as ``std::time_t`` value into calendar time,
@@ -468,7 +462,7 @@ inline std::tm localtime(std::time_t time) {
 
     bool fallback(int res) { return res == 0; }
 
-#if !FMT_MSC_VER
+#if !FMT_MSC_VERSION
     bool fallback(detail::null<>) {
       using namespace fmt::detail;
       std::tm* tm = std::localtime(&time_);
@@ -483,10 +477,13 @@ inline std::tm localtime(std::time_t time) {
   return lt.tm_;
 }
 
-inline std::tm localtime(
-    std::chrono::time_point<std::chrono::system_clock> time_point) {
-  return localtime(std::chrono::system_clock::to_time_t(time_point));
+#if FMT_USE_LOCAL_TIME
+template <typename Duration>
+inline auto localtime(std::chrono::local_time<Duration> time) -> std::tm {
+  return localtime(std::chrono::system_clock::to_time_t(
+      std::chrono::current_zone()->to_sys(time)));
 }
+#endif
 
 /**
   Converts given time since epoch as ``std::time_t`` value into calendar time,
@@ -514,7 +511,7 @@ inline std::tm gmtime(std::time_t time) {
 
     bool fallback(int res) { return res == 0; }
 
-#if !FMT_MSC_VER
+#if !FMT_MSC_VERSION
     bool fallback(detail::null<>) {
       std::tm* tm = std::gmtime(&time_);
       if (tm) tm_ = *tm;
@@ -535,6 +532,49 @@ inline std::tm gmtime(
 
 FMT_BEGIN_DETAIL_NAMESPACE
 
+// DEPRECATED!
+template <typename Char>
+FMT_CONSTEXPR auto parse_align(const Char* begin, const Char* end,
+                               format_specs<Char>& specs) -> const Char* {
+  FMT_ASSERT(begin != end, "");
+  auto align = align::none;
+  auto p = begin + code_point_length(begin);
+  if (end - p <= 0) p = begin;
+  for (;;) {
+    switch (to_ascii(*p)) {
+    case '<':
+      align = align::left;
+      break;
+    case '>':
+      align = align::right;
+      break;
+    case '^':
+      align = align::center;
+      break;
+    }
+    if (align != align::none) {
+      if (p != begin) {
+        auto c = *begin;
+        if (c == '}') return begin;
+        if (c == '{') {
+          throw_format_error("invalid fill character '{'");
+          return begin;
+        }
+        specs.fill = {begin, to_unsigned(p - begin)};
+        begin = p + 1;
+      } else {
+        ++begin;
+      }
+      break;
+    } else if (p == begin) {
+      break;
+    }
+    p = begin;
+  }
+  specs.align = align;
+  return begin;
+}
+
 // Writes two-digit numbers a, b and c separated by sep to buf.
 // The method by Pavel Novikov based on
 // https://johnnylee-sde.github.io/Fast-unsigned-integer-to-time-string/.
@@ -562,10 +602,10 @@ inline void write_digit2_separated(char* buf, unsigned a, unsigned b,
   constexpr const size_t len = 8;
   if (const_check(is_big_endian())) {
     char tmp[len];
-    memcpy(tmp, &digits, len);
+    std::memcpy(tmp, &digits, len);
     std::reverse_copy(tmp, tmp + len, buf);
   } else {
-    memcpy(buf, &digits, len);
+    std::memcpy(buf, &digits, len);
   }
 }
 
@@ -598,12 +638,39 @@ enum class numeric_system {
   alternative
 };
 
+// Glibc extensions for formatting numeric values.
+enum class pad_type {
+  unspecified,
+  // Do not pad a numeric result string.
+  none,
+  // Pad a numeric result string with zeros even if the conversion specifier
+  // character uses space-padding by default.
+  zero,
+  // Pad a numeric result string with spaces.
+  space,
+};
+
+template <typename OutputIt>
+auto write_padding(OutputIt out, pad_type pad, int width) -> OutputIt {
+  if (pad == pad_type::none) return out;
+  return std::fill_n(out, width, pad == pad_type::space ? ' ' : '0');
+}
+
+template <typename OutputIt>
+auto write_padding(OutputIt out, pad_type pad) -> OutputIt {
+  if (pad != pad_type::none) *out++ = pad == pad_type::space ? ' ' : '0';
+  return out;
+}
+
 // Parses a put_time-like format string and invokes handler actions.
 template <typename Char, typename Handler>
 FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
                                               const Char* end,
                                               Handler&& handler) {
+  if (begin == end || *begin == '}') return begin;
+  if (*begin != '%') FMT_THROW(format_error("invalid format"));
   auto ptr = begin;
+  pad_type pad = pad_type::unspecified;
   while (ptr != end) {
     auto c = *ptr;
     if (c == '}') break;
@@ -614,6 +681,22 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
     if (begin != ptr) handler.on_text(begin, ptr);
     ++ptr;  // consume '%'
     if (ptr == end) FMT_THROW(format_error("invalid format"));
+    c = *ptr;
+    switch (c) {
+    case '_':
+      pad = pad_type::space;
+      ++ptr;
+      break;
+    case '-':
+      pad = pad_type::none;
+      ++ptr;
+      break;
+    case '0':
+      pad = pad_type::zero;
+      ++ptr;
+      break;
+    }
+    if (ptr == end) FMT_THROW(format_error("invalid format"));
     c = *ptr++;
     switch (c) {
     case '%':
@@ -690,16 +773,16 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
       break;
     // Hour, minute, second:
     case 'H':
-      handler.on_24_hour(numeric_system::standard);
+      handler.on_24_hour(numeric_system::standard, pad);
       break;
     case 'I':
-      handler.on_12_hour(numeric_system::standard);
+      handler.on_12_hour(numeric_system::standard, pad);
       break;
     case 'M':
-      handler.on_minute(numeric_system::standard);
+      handler.on_minute(numeric_system::standard, pad);
       break;
     case 'S':
-      handler.on_second(numeric_system::standard);
+      handler.on_second(numeric_system::standard, pad);
       break;
     // Other:
     case 'c':
@@ -736,7 +819,7 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
       handler.on_duration_unit();
       break;
     case 'z':
-      handler.on_utc_offset();
+      handler.on_utc_offset(numeric_system::standard);
       break;
     case 'Z':
       handler.on_tz_name();
@@ -764,6 +847,9 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
       case 'X':
         handler.on_loc_time(numeric_system::alternative);
         break;
+      case 'z':
+        handler.on_utc_offset(numeric_system::alternative);
+        break;
       default:
         FMT_THROW(format_error("invalid format"));
       }
@@ -801,16 +887,19 @@ FMT_CONSTEXPR const Char* parse_chrono_format(const Char* begin,
         handler.on_dec1_weekday(numeric_system::alternative);
         break;
       case 'H':
-        handler.on_24_hour(numeric_system::alternative);
+        handler.on_24_hour(numeric_system::alternative, pad);
         break;
       case 'I':
-        handler.on_12_hour(numeric_system::alternative);
+        handler.on_12_hour(numeric_system::alternative, pad);
         break;
       case 'M':
-        handler.on_minute(numeric_system::alternative);
+        handler.on_minute(numeric_system::alternative, pad);
         break;
       case 'S':
-        handler.on_second(numeric_system::alternative);
+        handler.on_second(numeric_system::alternative, pad);
+        break;
+      case 'z':
+        handler.on_utc_offset(numeric_system::alternative);
         break;
       default:
         FMT_THROW(format_error("invalid format"));
@@ -863,7 +952,7 @@ template <typename Derived> struct null_chrono_spec_handler {
   FMT_CONSTEXPR void on_am_pm() { unsupported(); }
   FMT_CONSTEXPR void on_duration_value() { unsupported(); }
   FMT_CONSTEXPR void on_duration_unit() { unsupported(); }
-  FMT_CONSTEXPR void on_utc_offset() { unsupported(); }
+  FMT_CONSTEXPR void on_utc_offset(numeric_system) { unsupported(); }
   FMT_CONSTEXPR void on_tz_name() { unsupported(); }
 };
 
@@ -891,10 +980,10 @@ struct tm_format_checker : null_chrono_spec_handler<tm_format_checker> {
   FMT_CONSTEXPR void on_day_of_year() {}
   FMT_CONSTEXPR void on_day_of_month(numeric_system) {}
   FMT_CONSTEXPR void on_day_of_month_space(numeric_system) {}
-  FMT_CONSTEXPR void on_24_hour(numeric_system) {}
-  FMT_CONSTEXPR void on_12_hour(numeric_system) {}
-  FMT_CONSTEXPR void on_minute(numeric_system) {}
-  FMT_CONSTEXPR void on_second(numeric_system) {}
+  FMT_CONSTEXPR void on_24_hour(numeric_system, pad_type) {}
+  FMT_CONSTEXPR void on_12_hour(numeric_system, pad_type) {}
+  FMT_CONSTEXPR void on_minute(numeric_system, pad_type) {}
+  FMT_CONSTEXPR void on_second(numeric_system, pad_type) {}
   FMT_CONSTEXPR void on_datetime(numeric_system) {}
   FMT_CONSTEXPR void on_loc_date(numeric_system) {}
   FMT_CONSTEXPR void on_loc_time(numeric_system) {}
@@ -904,7 +993,7 @@ struct tm_format_checker : null_chrono_spec_handler<tm_format_checker> {
   FMT_CONSTEXPR void on_24_hour_time() {}
   FMT_CONSTEXPR void on_iso_time() {}
   FMT_CONSTEXPR void on_am_pm() {}
-  FMT_CONSTEXPR void on_utc_offset() {}
+  FMT_CONSTEXPR void on_utc_offset(numeric_system) {}
   FMT_CONSTEXPR void on_tz_name() {}
 };
 
@@ -956,13 +1045,130 @@ inline void tzset_once() {
 }
 #endif
 
-template <typename OutputIt, typename Char> class tm_writer {
+// Converts value to Int and checks that it's in the range [0, upper).
+template <typename T, typename Int, FMT_ENABLE_IF(std::is_integral<T>::value)>
+inline Int to_nonnegative_int(T value, Int upper) {
+  FMT_ASSERT(std::is_unsigned<Int>::value ||
+                 (value >= 0 && to_unsigned(value) <= to_unsigned(upper)),
+             "invalid value");
+  (void)upper;
+  return static_cast<Int>(value);
+}
+template <typename T, typename Int, FMT_ENABLE_IF(!std::is_integral<T>::value)>
+inline Int to_nonnegative_int(T value, Int upper) {
+  if (value < 0 || value > static_cast<T>(upper))
+    FMT_THROW(format_error("invalid value"));
+  return static_cast<Int>(value);
+}
+
+constexpr long long pow10(std::uint32_t n) {
+  return n == 0 ? 1 : 10 * pow10(n - 1);
+}
+
+// Counts the number of fractional digits in the range [0, 18] according to the
+// C++20 spec. If more than 18 fractional digits are required then returns 6 for
+// microseconds precision.
+template <long long Num, long long Den, int N = 0,
+          bool Enabled = (N < 19) && (Num <= max_value<long long>() / 10)>
+struct count_fractional_digits {
+  static constexpr int value =
+      Num % Den == 0 ? N : count_fractional_digits<Num * 10, Den, N + 1>::value;
+};
+
+// Base case that doesn't instantiate any more templates
+// in order to avoid overflow.
+template <long long Num, long long Den, int N>
+struct count_fractional_digits<Num, Den, N, false> {
+  static constexpr int value = (Num % Den == 0) ? N : 6;
+};
+
+// Format subseconds which are given as an integer type with an appropriate
+// number of digits.
+template <typename Char, typename OutputIt, typename Duration>
+void write_fractional_seconds(OutputIt& out, Duration d, int precision = -1) {
+  constexpr auto num_fractional_digits =
+      count_fractional_digits<Duration::period::num,
+                              Duration::period::den>::value;
+
+  using subsecond_precision = std::chrono::duration<
+      typename std::common_type<typename Duration::rep,
+                                std::chrono::seconds::rep>::type,
+      std::ratio<1, detail::pow10(num_fractional_digits)>>;
+
+  const auto fractional =
+      d - std::chrono::duration_cast<std::chrono::seconds>(d);
+  const auto subseconds =
+      std::chrono::treat_as_floating_point<
+          typename subsecond_precision::rep>::value
+          ? fractional.count()
+          : std::chrono::duration_cast<subsecond_precision>(fractional).count();
+  auto n = static_cast<uint32_or_64_or_128_t<long long>>(subseconds);
+  const int num_digits = detail::count_digits(n);
+
+  int leading_zeroes = (std::max)(0, num_fractional_digits - num_digits);
+  if (precision < 0) {
+    FMT_ASSERT(!std::is_floating_point<typename Duration::rep>::value, "");
+    if (std::ratio_less<typename subsecond_precision::period,
+                        std::chrono::seconds::period>::value) {
+      *out++ = '.';
+      out = std::fill_n(out, leading_zeroes, '0');
+      out = format_decimal<Char>(out, n, num_digits).end;
+    }
+  } else {
+    *out++ = '.';
+    leading_zeroes = (std::min)(leading_zeroes, precision);
+    out = std::fill_n(out, leading_zeroes, '0');
+    int remaining = precision - leading_zeroes;
+    if (remaining != 0 && remaining < num_digits) {
+      n /= to_unsigned(detail::pow10(to_unsigned(num_digits - remaining)));
+      out = format_decimal<Char>(out, n, remaining).end;
+      return;
+    }
+    out = format_decimal<Char>(out, n, num_digits).end;
+    remaining -= num_digits;
+    out = std::fill_n(out, remaining, '0');
+  }
+}
+
+// Format subseconds which are given as a floating point type with an
+// appropriate number of digits. We cannot pass the Duration here, as we
+// explicitly need to pass the Rep value in the chrono_formatter.
+template <typename Duration>
+void write_floating_seconds(memory_buffer& buf, Duration duration,
+                            int num_fractional_digits = -1) {
+  using rep = typename Duration::rep;
+  FMT_ASSERT(std::is_floating_point<rep>::value, "");
+
+  auto val = duration.count();
+
+  if (num_fractional_digits < 0) {
+    // For `std::round` with fallback to `round`:
+    // On some toolchains `std::round` is not available (e.g. GCC 6).
+    using namespace std;
+    num_fractional_digits =
+        count_fractional_digits<Duration::period::num,
+                                Duration::period::den>::value;
+    if (num_fractional_digits < 6 && static_cast<rep>(round(val)) != val)
+      num_fractional_digits = 6;
+  }
+
+  format_to(std::back_inserter(buf), FMT_STRING("{:.{}f}"),
+            std::fmod(val * static_cast<rep>(Duration::period::num) /
+                          static_cast<rep>(Duration::period::den),
+                      static_cast<rep>(60)),
+            num_fractional_digits);
+}
+
+template <typename OutputIt, typename Char,
+          typename Duration = std::chrono::seconds>
+class tm_writer {
  private:
   static constexpr int days_per_week = 7;
 
   const std::locale& loc_;
   const bool is_classic_;
   OutputIt out_;
+  const Duration* subsecs_;
   const std::tm& tm_;
 
   auto tm_sec() const noexcept -> int {
@@ -1050,6 +1256,17 @@ template <typename OutputIt, typename Char> class tm_writer {
     *out_++ = *d++;
     *out_++ = *d;
   }
+  void write2(int value, pad_type pad) {
+    unsigned int v = to_unsigned(value) % 100;
+    if (v >= 10) {
+      const char* d = digits2(v);
+      *out_++ = *d++;
+      *out_++ = *d;
+    } else {
+      out_ = detail::write_padding(out_, pad);
+      *out_++ = static_cast<char>('0' + v);
+    }
+  }
 
   void write_year_extended(long long year) {
     // At least 4 characters.
@@ -1073,7 +1290,7 @@ template <typename OutputIt, typename Char> class tm_writer {
     }
   }
 
-  void write_utc_offset(long offset) {
+  void write_utc_offset(long offset, numeric_system ns) {
     if (offset < 0) {
       *out_++ = '-';
       offset = -offset;
@@ -1082,14 +1299,15 @@ template <typename OutputIt, typename Char> class tm_writer {
     }
     offset /= 60;
     write2(static_cast<int>(offset / 60));
+    if (ns != numeric_system::standard) *out_++ = ':';
     write2(static_cast<int>(offset % 60));
   }
   template <typename T, FMT_ENABLE_IF(has_member_data_tm_gmtoff<T>::value)>
-  void format_utc_offset_impl(const T& tm) {
-    write_utc_offset(tm.tm_gmtoff);
+  void format_utc_offset_impl(const T& tm, numeric_system ns) {
+    write_utc_offset(tm.tm_gmtoff, ns);
   }
   template <typename T, FMT_ENABLE_IF(!has_member_data_tm_gmtoff<T>::value)>
-  void format_utc_offset_impl(const T& tm) {
+  void format_utc_offset_impl(const T& tm, numeric_system ns) {
 #if defined(_WIN32) && defined(_UCRT)
 #  if FMT_USE_TZSET
     tzset_once();
@@ -1101,10 +1319,17 @@ template <typename OutputIt, typename Char> class tm_writer {
       _get_dstbias(&dstbias);
       offset += dstbias;
     }
-    write_utc_offset(-offset);
+    write_utc_offset(-offset, ns);
 #else
-    ignore_unused(tm);
-    format_localized('z');
+    if (ns == numeric_system::standard) return format_localized('z');
+
+    // Extract timezone offset from timezone conversion functions.
+    std::tm gtm = tm;
+    std::time_t gt = std::mktime(&gtm);
+    std::tm ltm = gmtime(gt);
+    std::time_t lt = std::mktime(&ltm);
+    long offset = gt - lt;
+    write_utc_offset(offset, ns);
 #endif
   }
 
@@ -1125,10 +1350,12 @@ template <typename OutputIt, typename Char> class tm_writer {
   }
 
  public:
-  tm_writer(const std::locale& loc, OutputIt out, const std::tm& tm)
+  tm_writer(const std::locale& loc, OutputIt out, const std::tm& tm,
+            const Duration* subsecs = nullptr)
       : loc_(loc),
         is_classic_(loc_ == get_classic_locale()),
         out_(out),
+        subsecs_(subsecs),
         tm_(tm) {}
 
   OutputIt out() const { return out_; }
@@ -1214,7 +1441,7 @@ template <typename OutputIt, typename Char> class tm_writer {
     char buf[10];
     size_t offset = 0;
     if (year >= 0 && year < 10000) {
-      copy2(buf, digits2(to_unsigned(year / 100)));
+      copy2(buf, digits2(static_cast<size_t>(year / 100)));
     } else {
       offset = 4;
       write_year_extended(year);
@@ -1226,7 +1453,7 @@ template <typename OutputIt, typename Char> class tm_writer {
     out_ = copy_str<Char>(std::begin(buf) + offset, std::end(buf), out_);
   }
 
-  void on_utc_offset() { format_utc_offset_impl(tm_); }
+  void on_utc_offset(numeric_system ns) { format_utc_offset_impl(tm_, ns); }
   void on_tz_name() { format_tz_name_impl(tm_); }
 
   void on_year(numeric_system ns) {
@@ -1314,22 +1541,41 @@ template <typename OutputIt, typename Char> class tm_writer {
     }
   }
 
-  void on_24_hour(numeric_system ns) {
-    if (is_classic_ || ns == numeric_system::standard) return write2(tm_hour());
+  void on_24_hour(numeric_system ns, pad_type pad) {
+    if (is_classic_ || ns == numeric_system::standard)
+      return write2(tm_hour(), pad);
     format_localized('H', 'O');
   }
-  void on_12_hour(numeric_system ns) {
+  void on_12_hour(numeric_system ns, pad_type pad) {
     if (is_classic_ || ns == numeric_system::standard)
-      return write2(tm_hour12());
+      return write2(tm_hour12(), pad);
     format_localized('I', 'O');
   }
-  void on_minute(numeric_system ns) {
-    if (is_classic_ || ns == numeric_system::standard) return write2(tm_min());
+  void on_minute(numeric_system ns, pad_type pad) {
+    if (is_classic_ || ns == numeric_system::standard)
+      return write2(tm_min(), pad);
     format_localized('M', 'O');
   }
-  void on_second(numeric_system ns) {
-    if (is_classic_ || ns == numeric_system::standard) return write2(tm_sec());
-    format_localized('S', 'O');
+
+  void on_second(numeric_system ns, pad_type pad) {
+    if (is_classic_ || ns == numeric_system::standard) {
+      write2(tm_sec(), pad);
+      if (subsecs_) {
+        if (std::is_floating_point<typename Duration::rep>::value) {
+          auto buf = memory_buffer();
+          write_floating_seconds(buf, *subsecs_);
+          if (buf.size() > 1) {
+            // Remove the leading "0", write something like ".123".
+            out_ = std::copy(buf.begin() + 1, buf.end(), out_);
+          }
+        } else {
+          write_fractional_seconds<Char>(out_, *subsecs_);
+        }
+      }
+    } else {
+      // Currently no formatting of subseconds when a locale is set.
+      format_localized('S', 'O');
+    }
   }
 
   void on_12_hour_time() {
@@ -1350,10 +1596,9 @@ template <typename OutputIt, typename Char> class tm_writer {
     write2(tm_min());
   }
   void on_iso_time() {
-    char buf[8];
-    write_digit2_separated(buf, to_unsigned(tm_hour()), to_unsigned(tm_min()),
-                           to_unsigned(tm_sec()), ':');
-    out_ = copy_str<Char>(std::begin(buf), std::end(buf), out_);
+    on_24_hour_time();
+    *out_++ = ':';
+    on_second(numeric_system::standard, pad_type::unspecified);
   }
 
   void on_am_pm() {
@@ -1371,51 +1616,34 @@ template <typename OutputIt, typename Char> class tm_writer {
 };
 
 struct chrono_format_checker : null_chrono_spec_handler<chrono_format_checker> {
+  bool has_precision_integral = false;
+
   FMT_NORETURN void unsupported() { FMT_THROW(format_error("no date")); }
 
   template <typename Char>
   FMT_CONSTEXPR void on_text(const Char*, const Char*) {}
-  FMT_CONSTEXPR void on_24_hour(numeric_system) {}
-  FMT_CONSTEXPR void on_12_hour(numeric_system) {}
-  FMT_CONSTEXPR void on_minute(numeric_system) {}
-  FMT_CONSTEXPR void on_second(numeric_system) {}
+  FMT_CONSTEXPR void on_24_hour(numeric_system, pad_type) {}
+  FMT_CONSTEXPR void on_12_hour(numeric_system, pad_type) {}
+  FMT_CONSTEXPR void on_minute(numeric_system, pad_type) {}
+  FMT_CONSTEXPR void on_second(numeric_system, pad_type) {}
   FMT_CONSTEXPR void on_12_hour_time() {}
   FMT_CONSTEXPR void on_24_hour_time() {}
   FMT_CONSTEXPR void on_iso_time() {}
   FMT_CONSTEXPR void on_am_pm() {}
-  FMT_CONSTEXPR void on_duration_value() {}
+  FMT_CONSTEXPR void on_duration_value() const {
+    if (has_precision_integral) {
+      FMT_THROW(format_error("precision not allowed for this argument type"));
+    }
+  }
   FMT_CONSTEXPR void on_duration_unit() {}
 };
 
-template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
-inline bool isnan(T) {
-  return false;
-}
-template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-inline bool isnan(T value) {
-  return std::isnan(value);
-}
-
-template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+template <typename T,
+          FMT_ENABLE_IF(std::is_integral<T>::value&& has_isfinite<T>::value)>
 inline bool isfinite(T) {
   return true;
 }
 
-// Converts value to Int and checks that it's in the range [0, upper).
-template <typename T, typename Int, FMT_ENABLE_IF(std::is_integral<T>::value)>
-inline Int to_nonnegative_int(T value, Int upper) {
-  FMT_ASSERT(value >= 0 && to_unsigned(value) <= to_unsigned(upper),
-             "invalid value");
-  (void)upper;
-  return static_cast<Int>(value);
-}
-template <typename T, typename Int, FMT_ENABLE_IF(!std::is_integral<T>::value)>
-inline Int to_nonnegative_int(T value, Int upper) {
-  if (value < 0 || value > static_cast<T>(upper))
-    FMT_THROW(format_error("invalid value"));
-  return static_cast<Int>(value);
-}
-
 template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
 inline T mod(T x, int y) {
   return x % static_cast<T>(y);
@@ -1470,39 +1698,6 @@ inline std::chrono::duration<Rep, std::milli> get_milliseconds(
 #endif
 }
 
-// Returns the number of fractional digits in the range [0, 18] according to the
-// C++20 spec. If more than 18 fractional digits are required then returns 6 for
-// microseconds precision.
-constexpr int count_fractional_digits(long long num, long long den, int n = 0) {
-  return num % den == 0
-             ? n
-             : (n > 18 ? 6 : count_fractional_digits(num * 10, den, n + 1));
-}
-
-constexpr long long pow10(std::uint32_t n) {
-  return n == 0 ? 1 : 10 * pow10(n - 1);
-}
-
-template <class Rep, class Period,
-          FMT_ENABLE_IF(std::numeric_limits<Rep>::is_signed)>
-constexpr std::chrono::duration<Rep, Period> abs(
-    std::chrono::duration<Rep, Period> d) {
-  // We need to compare the duration using the count() method directly
-  // due to a compiler bug in clang-11 regarding the spaceship operator,
-  // when -Wzero-as-null-pointer-constant is enabled.
-  // In clang-12 the bug has been fixed. See
-  // https://bugs.llvm.org/show_bug.cgi?id=46235 and the reproducible example:
-  // https://www.godbolt.org/z/Knbb5joYx.
-  return d.count() >= d.zero().count() ? d : -d;
-}
-
-template <class Rep, class Period,
-          FMT_ENABLE_IF(!std::numeric_limits<Rep>::is_signed)>
-constexpr std::chrono::duration<Rep, Period> abs(
-    std::chrono::duration<Rep, Period> d) {
-  return d;
-}
-
 template <typename Char, typename Rep, typename OutputIt,
           FMT_ENABLE_IF(std::is_integral<Rep>::value)>
 OutputIt format_duration_value(OutputIt out, Rep val, int) {
@@ -1512,7 +1707,7 @@ OutputIt format_duration_value(OutputIt out, Rep val, int) {
 template <typename Char, typename Rep, typename OutputIt,
           FMT_ENABLE_IF(std::is_floating_point<Rep>::value)>
 OutputIt format_duration_value(OutputIt out, Rep val, int precision) {
-  auto specs = basic_format_specs<Char>();
+  auto specs = format_specs<Char>();
   specs.precision = precision;
   specs.type = precision >= 0 ? presentation_type::fixed_lower
                               : presentation_type::general_lower;
@@ -1653,45 +1848,16 @@ struct chrono_formatter {
     }
   }
 
-  void write(Rep value, int width) {
+  void write(Rep value, int width, pad_type pad = pad_type::unspecified) {
     write_sign();
     if (isnan(value)) return write_nan();
     uint32_or_64_or_128_t<int> n =
         to_unsigned(to_nonnegative_int(value, max_value<int>()));
     int num_digits = detail::count_digits(n);
-    if (width > num_digits) out = std::fill_n(out, width - num_digits, '0');
-    out = format_decimal<char_type>(out, n, num_digits).end;
-  }
-
-  template <class Duration> void write_fractional_seconds(Duration d) {
-    constexpr auto num_fractional_digits =
-        count_fractional_digits(Duration::period::num, Duration::period::den);
-
-    using subsecond_precision = std::chrono::duration<
-        typename std::common_type<typename Duration::rep,
-                                  std::chrono::seconds::rep>::type,
-        std::ratio<1, detail::pow10(num_fractional_digits)>>;
-    if (std::ratio_less<typename subsecond_precision::period,
-                        std::chrono::seconds::period>::value) {
-      *out++ = '.';
-      // Don't convert long double to integer seconds to avoid overflow.
-      using sec = conditional_t<
-          std::is_same<typename Duration::rep, long double>::value,
-          std::chrono::duration<long double>, std::chrono::seconds>;
-      auto fractional = detail::abs(d) - std::chrono::duration_cast<sec>(d);
-      const auto subseconds =
-          std::chrono::treat_as_floating_point<
-              typename subsecond_precision::rep>::value
-              ? fractional.count()
-              : std::chrono::duration_cast<subsecond_precision>(fractional)
-                    .count();
-      uint32_or_64_or_128_t<long long> n =
-          to_unsigned(to_nonnegative_int(subseconds, max_value<long long>()));
-      int num_digits = detail::count_digits(n);
-      if (num_fractional_digits > num_digits)
-        out = std::fill_n(out, num_fractional_digits - num_digits, '0');
-      out = format_decimal<char_type>(out, n, num_digits).end;
+    if (width > num_digits) {
+      out = detail::write_padding(out, pad, width - num_digits);
     }
+    out = format_decimal<char_type>(out, n, num_digits).end;
   }
 
   void write_nan() { std::copy_n("nan", 3, out); }
@@ -1723,7 +1889,7 @@ struct chrono_formatter {
   void on_loc_time(numeric_system) {}
   void on_us_date() {}
   void on_iso_date() {}
-  void on_utc_offset() {}
+  void on_utc_offset(numeric_system) {}
   void on_tz_name() {}
   void on_year(numeric_system) {}
   void on_short_year(numeric_system) {}
@@ -1739,44 +1905,56 @@ struct chrono_formatter {
   void on_day_of_month(numeric_system) {}
   void on_day_of_month_space(numeric_system) {}
 
-  void on_24_hour(numeric_system ns) {
+  void on_24_hour(numeric_system ns, pad_type pad) {
     if (handle_nan_inf()) return;
 
-    if (ns == numeric_system::standard) return write(hour(), 2);
+    if (ns == numeric_system::standard) return write(hour(), 2, pad);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour(), 24);
-    format_tm(time, &tm_writer_type::on_24_hour, ns);
+    format_tm(time, &tm_writer_type::on_24_hour, ns, pad);
   }
 
-  void on_12_hour(numeric_system ns) {
+  void on_12_hour(numeric_system ns, pad_type pad) {
     if (handle_nan_inf()) return;
 
-    if (ns == numeric_system::standard) return write(hour12(), 2);
+    if (ns == numeric_system::standard) return write(hour12(), 2, pad);
     auto time = tm();
     time.tm_hour = to_nonnegative_int(hour12(), 12);
-    format_tm(time, &tm_writer_type::on_12_hour, ns);
+    format_tm(time, &tm_writer_type::on_12_hour, ns, pad);
   }
 
-  void on_minute(numeric_system ns) {
+  void on_minute(numeric_system ns, pad_type pad) {
     if (handle_nan_inf()) return;
 
-    if (ns == numeric_system::standard) return write(minute(), 2);
+    if (ns == numeric_system::standard) return write(minute(), 2, pad);
     auto time = tm();
     time.tm_min = to_nonnegative_int(minute(), 60);
-    format_tm(time, &tm_writer_type::on_minute, ns);
+    format_tm(time, &tm_writer_type::on_minute, ns, pad);
   }
 
-  void on_second(numeric_system ns) {
+  void on_second(numeric_system ns, pad_type pad) {
     if (handle_nan_inf()) return;
 
     if (ns == numeric_system::standard) {
-      write(second(), 2);
-      write_fractional_seconds(std::chrono::duration<rep, Period>{val});
+      if (std::is_floating_point<rep>::value) {
+        auto buf = memory_buffer();
+        write_floating_seconds(buf, std::chrono::duration<rep, Period>(val),
+                               precision);
+        if (negative) *out++ = '-';
+        if (buf.size() < 2 || buf[1] == '.') {
+          out = detail::write_padding(out, pad);
+        }
+        out = std::copy(buf.begin(), buf.end(), out);
+      } else {
+        write(second(), 2, pad);
+        write_fractional_seconds<char_type>(
+            out, std::chrono::duration<rep, Period>(val), precision);
+      }
       return;
     }
     auto time = tm();
     time.tm_sec = to_nonnegative_int(second(), 60);
-    format_tm(time, &tm_writer_type::on_second, ns);
+    format_tm(time, &tm_writer_type::on_second, ns, pad);
   }
 
   void on_12_hour_time() {
@@ -1800,7 +1978,7 @@ struct chrono_formatter {
     on_24_hour_time();
     *out++ = ':';
     if (handle_nan_inf()) return;
-    on_second(numeric_system::standard);
+    on_second(numeric_system::standard, pad_type::unspecified);
   }
 
   void on_am_pm() {
@@ -1869,7 +2047,7 @@ template <typename Char> struct formatter<weekday, Char> {
 template <typename Rep, typename Period, typename Char>
 struct formatter<std::chrono::duration<Rep, Period>, Char> {
  private:
-  basic_format_specs<Char> specs;
+  format_specs<Char> specs;
   int precision = -1;
   using arg_ref_type = detail::arg_ref<Char>;
   arg_ref_type width_ref;
@@ -1878,45 +2056,6 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
   basic_string_view<Char> format_str;
   using duration = std::chrono::duration<Rep, Period>;
 
-  struct spec_handler {
-    formatter& f;
-    basic_format_parse_context<Char>& context;
-    basic_string_view<Char> format_str;
-
-    template <typename Id> FMT_CONSTEXPR arg_ref_type make_arg_ref(Id arg_id) {
-      context.check_arg_id(arg_id);
-      return arg_ref_type(arg_id);
-    }
-
-    FMT_CONSTEXPR arg_ref_type make_arg_ref(basic_string_view<Char> arg_id) {
-      context.check_arg_id(arg_id);
-      return arg_ref_type(arg_id);
-    }
-
-    FMT_CONSTEXPR arg_ref_type make_arg_ref(detail::auto_id) {
-      return arg_ref_type(context.next_arg_id());
-    }
-
-    void on_error(const char* msg) { FMT_THROW(format_error(msg)); }
-    FMT_CONSTEXPR void on_fill(basic_string_view<Char> fill) {
-      f.specs.fill = fill;
-    }
-    FMT_CONSTEXPR void on_align(align_t align) { f.specs.align = align; }
-    FMT_CONSTEXPR void on_width(int width) { f.specs.width = width; }
-    FMT_CONSTEXPR void on_precision(int _precision) {
-      f.precision = _precision;
-    }
-    FMT_CONSTEXPR void end_precision() {}
-
-    template <typename Id> FMT_CONSTEXPR void on_dynamic_width(Id arg_id) {
-      f.width_ref = make_arg_ref(arg_id);
-    }
-
-    template <typename Id> FMT_CONSTEXPR void on_dynamic_precision(Id arg_id) {
-      f.precision_ref = make_arg_ref(arg_id);
-    }
-  };
-
   using iterator = typename basic_format_parse_context<Char>::iterator;
   struct parse_range {
     iterator begin;
@@ -1926,23 +2065,24 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
   FMT_CONSTEXPR parse_range do_parse(basic_format_parse_context<Char>& ctx) {
     auto begin = ctx.begin(), end = ctx.end();
     if (begin == end || *begin == '}') return {begin, begin};
-    spec_handler handler{*this, ctx, format_str};
-    begin = detail::parse_align(begin, end, handler);
+
+    begin = detail::parse_align(begin, end, specs);
     if (begin == end) return {begin, begin};
-    begin = detail::parse_width(begin, end, handler);
+
+    begin = detail::parse_dynamic_spec(begin, end, specs.width, width_ref, ctx);
     if (begin == end) return {begin, begin};
+
+    auto checker = detail::chrono_format_checker();
     if (*begin == '.') {
-      if (std::is_floating_point<Rep>::value)
-        begin = detail::parse_precision(begin, end, handler);
-      else
-        handler.on_error("precision not allowed for this argument type");
+      checker.has_precision_integral = !std::is_floating_point<Rep>::value;
+      begin =
+          detail::parse_precision(begin, end, precision, precision_ref, ctx);
     }
     if (begin != end && *begin == 'L') {
       ++begin;
       localized = true;
     }
-    end = detail::parse_chrono_format(begin, end,
-                                      detail::chrono_format_checker());
+    end = detail::parse_chrono_format(begin, end, checker);
     return {begin, end};
   }
 
@@ -1988,80 +2128,140 @@ template <typename Char, typename Duration>
 struct formatter<std::chrono::time_point<std::chrono::system_clock, Duration>,
                  Char> : formatter<std::tm, Char> {
   FMT_CONSTEXPR formatter() {
-    this->do_parse(default_specs,
-                   default_specs + sizeof(default_specs) / sizeof(Char));
-  }
-
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return this->do_parse(ctx.begin(), ctx.end(), true);
+    this->format_str = detail::string_literal<Char, '%', 'F', ' ', '%', 'T'>{};
   }
 
   template <typename FormatContext>
-  auto format(std::chrono::time_point<std::chrono::system_clock> val,
+  auto format(std::chrono::time_point<std::chrono::system_clock, Duration> val,
               FormatContext& ctx) const -> decltype(ctx.out()) {
-    return formatter<std::tm, Char>::format(localtime(val), ctx);
+    using period = typename Duration::period;
+    if (period::num != 1 || period::den != 1 ||
+        std::is_floating_point<typename Duration::rep>::value) {
+      const auto epoch = val.time_since_epoch();
+      auto subsecs = std::chrono::duration_cast<Duration>(
+          epoch - std::chrono::duration_cast<std::chrono::seconds>(epoch));
+
+      if (subsecs.count() < 0) {
+        auto second = std::chrono::seconds(1);
+        if (epoch.count() < ((Duration::min)() + second).count())
+          FMT_THROW(format_error("duration is too small"));
+        subsecs += second;
+        val -= second;
+      }
+
+      return formatter<std::tm, Char>::do_format(
+          gmtime(std::chrono::time_point_cast<std::chrono::seconds>(val)), ctx,
+          &subsecs);
+    }
+
+    return formatter<std::tm, Char>::format(
+        gmtime(std::chrono::time_point_cast<std::chrono::seconds>(val)), ctx);
   }
+};
 
-  static constexpr const Char default_specs[] = {'%', 'F', ' ', '%', 'T'};
+#if FMT_USE_LOCAL_TIME
+template <typename Char, typename Duration>
+struct formatter<std::chrono::local_time<Duration>, Char>
+    : formatter<std::tm, Char> {
+  FMT_CONSTEXPR formatter() {
+    this->format_str = detail::string_literal<Char, '%', 'F', ' ', '%', 'T'>{};
+  }
+
+  template <typename FormatContext>
+  auto format(std::chrono::local_time<Duration> val, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    using period = typename Duration::period;
+    if (period::num != 1 || period::den != 1 ||
+        std::is_floating_point<typename Duration::rep>::value) {
+      const auto epoch = val.time_since_epoch();
+      const auto subsecs = std::chrono::duration_cast<Duration>(
+          epoch - std::chrono::duration_cast<std::chrono::seconds>(epoch));
+
+      return formatter<std::tm, Char>::do_format(
+          localtime(std::chrono::time_point_cast<std::chrono::seconds>(val)),
+          ctx, &subsecs);
+    }
+
+    return formatter<std::tm, Char>::format(
+        localtime(std::chrono::time_point_cast<std::chrono::seconds>(val)),
+        ctx);
+  }
 };
+#endif
 
+#if FMT_USE_UTC_TIME
 template <typename Char, typename Duration>
-constexpr const Char
-    formatter<std::chrono::time_point<std::chrono::system_clock, Duration>,
-              Char>::default_specs[];
+struct formatter<std::chrono::time_point<std::chrono::utc_clock, Duration>,
+                 Char>
+    : formatter<std::chrono::time_point<std::chrono::system_clock, Duration>,
+                Char> {
+  template <typename FormatContext>
+  auto format(std::chrono::time_point<std::chrono::utc_clock, Duration> val,
+              FormatContext& ctx) const -> decltype(ctx.out()) {
+    return formatter<
+        std::chrono::time_point<std::chrono::system_clock, Duration>,
+        Char>::format(std::chrono::utc_clock::to_sys(val), ctx);
+  }
+};
+#endif
 
 template <typename Char> struct formatter<std::tm, Char> {
  private:
-  enum class spec {
-    unknown,
-    year_month_day,
-    hh_mm_ss,
-  };
-  spec spec_ = spec::unknown;
-  basic_string_view<Char> specs;
+  format_specs<Char> specs;
+  detail::arg_ref<Char> width_ref;
 
  protected:
-  template <typename It>
-  FMT_CONSTEXPR auto do_parse(It begin, It end, bool with_default = false)
-      -> It {
-    if (begin != end && *begin == ':') ++begin;
+  basic_string_view<Char> format_str;
+
+  FMT_CONSTEXPR auto do_parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    auto begin = ctx.begin(), end = ctx.end();
+    if (begin == end || *begin == '}') return begin;
+
+    begin = detail::parse_align(begin, end, specs);
+    if (begin == end) return end;
+
+    begin = detail::parse_dynamic_spec(begin, end, specs.width, width_ref, ctx);
+    if (begin == end) return end;
+
     end = detail::parse_chrono_format(begin, end, detail::tm_format_checker());
-    if (!with_default || end != begin)
-      specs = {begin, detail::to_unsigned(end - begin)};
-    // basic_string_view<>::compare isn't constexpr before C++17.
-    if (specs.size() == 2 && specs[0] == Char('%')) {
-      if (specs[1] == Char('F'))
-        spec_ = spec::year_month_day;
-      else if (specs[1] == Char('T'))
-        spec_ = spec::hh_mm_ss;
-    }
+    // Replace default format_str only if the new spec is not empty.
+    if (end != begin) format_str = {begin, detail::to_unsigned(end - begin)};
     return end;
   }
 
+  template <typename FormatContext, typename Duration>
+  auto do_format(const std::tm& tm, FormatContext& ctx,
+                 const Duration* subsecs) const -> decltype(ctx.out()) {
+    auto specs_copy = specs;
+    basic_memory_buffer<Char> buf;
+    auto out = std::back_inserter(buf);
+    detail::handle_dynamic_spec<detail::width_checker>(specs_copy.width,
+                                                       width_ref, ctx);
+
+    const auto loc_ref = ctx.locale();
+    detail::get_locale loc(static_cast<bool>(loc_ref), loc_ref);
+    auto w =
+        detail::tm_writer<decltype(out), Char, Duration>(loc, out, tm, subsecs);
+    detail::parse_chrono_format(format_str.begin(), format_str.end(), w);
+    return detail::write(
+        ctx.out(), basic_string_view<Char>(buf.data(), buf.size()), specs_copy);
+  }
+
  public:
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return this->do_parse(ctx.begin(), ctx.end());
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    return this->do_parse(ctx);
   }
 
   template <typename FormatContext>
   auto format(const std::tm& tm, FormatContext& ctx) const
       -> decltype(ctx.out()) {
-    const auto loc_ref = ctx.locale();
-    detail::get_locale loc(static_cast<bool>(loc_ref), loc_ref);
-    auto w = detail::tm_writer<decltype(ctx.out()), Char>(loc, ctx.out(), tm);
-    if (spec_ == spec::year_month_day)
-      w.on_iso_date();
-    else if (spec_ == spec::hh_mm_ss)
-      w.on_iso_time();
-    else
-      detail::parse_chrono_format(specs.begin(), specs.end(), w);
-    return w.out();
+    return do_format<FormatContext, std::chrono::seconds>(tm, ctx, nullptr);
   }
 };
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_CHRONO_H_
diff --git a/contrib/fmt/include/fmt/color.h b/contrib/fmt/include/fmt/color.h
index dfbe48293..d175448ab 100644
--- a/contrib/fmt/include/fmt/color.h
+++ b/contrib/fmt/include/fmt/color.h
@@ -10,15 +10,8 @@
 
 #include "format.h"
 
-// __declspec(deprecated) is broken in some MSVC versions.
-#if FMT_MSC_VER
-#  define FMT_DEPRECATED_NONMSVC
-#else
-#  define FMT_DEPRECATED_NONMSVC FMT_DEPRECATED
-#endif
-
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 enum class color : uint32_t {
   alice_blue = 0xF0F8FF,               // rgb(240,248,255)
@@ -214,17 +207,16 @@ FMT_BEGIN_DETAIL_NAMESPACE
 
 // color is a struct of either a rgb color or a terminal color.
 struct color_type {
-  FMT_CONSTEXPR color_type() FMT_NOEXCEPT : is_rgb(), value{} {}
-  FMT_CONSTEXPR color_type(color rgb_color) FMT_NOEXCEPT : is_rgb(true),
-                                                           value{} {
+  FMT_CONSTEXPR color_type() noexcept : is_rgb(), value{} {}
+  FMT_CONSTEXPR color_type(color rgb_color) noexcept : is_rgb(true), value{} {
     value.rgb_color = static_cast<uint32_t>(rgb_color);
   }
-  FMT_CONSTEXPR color_type(rgb rgb_color) FMT_NOEXCEPT : is_rgb(true), value{} {
+  FMT_CONSTEXPR color_type(rgb rgb_color) noexcept : is_rgb(true), value{} {
     value.rgb_color = (static_cast<uint32_t>(rgb_color.r) << 16) |
                       (static_cast<uint32_t>(rgb_color.g) << 8) | rgb_color.b;
   }
-  FMT_CONSTEXPR color_type(terminal_color term_color) FMT_NOEXCEPT : is_rgb(),
-                                                                     value{} {
+  FMT_CONSTEXPR color_type(terminal_color term_color) noexcept
+      : is_rgb(), value{} {
     value.term_color = static_cast<uint8_t>(term_color);
   }
   bool is_rgb;
@@ -239,10 +231,8 @@ FMT_END_DETAIL_NAMESPACE
 /** A text style consisting of foreground and background colors and emphasis. */
 class text_style {
  public:
-  FMT_CONSTEXPR text_style(emphasis em = emphasis()) FMT_NOEXCEPT
-      : set_foreground_color(),
-        set_background_color(),
-        ems(em) {}
+  FMT_CONSTEXPR text_style(emphasis em = emphasis()) noexcept
+      : set_foreground_color(), set_background_color(), ems(em) {}
 
   FMT_CONSTEXPR text_style& operator|=(const text_style& rhs) {
     if (!set_foreground_color) {
@@ -273,44 +263,32 @@ class text_style {
     return lhs |= rhs;
   }
 
-  FMT_DEPRECATED_NONMSVC FMT_CONSTEXPR text_style& operator&=(
-      const text_style& rhs) {
-    return and_assign(rhs);
-  }
-
-  FMT_DEPRECATED_NONMSVC friend FMT_CONSTEXPR text_style
-  operator&(text_style lhs, const text_style& rhs) {
-    return lhs.and_assign(rhs);
-  }
-
-  FMT_CONSTEXPR bool has_foreground() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_foreground() const noexcept {
     return set_foreground_color;
   }
-  FMT_CONSTEXPR bool has_background() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_background() const noexcept {
     return set_background_color;
   }
-  FMT_CONSTEXPR bool has_emphasis() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR bool has_emphasis() const noexcept {
     return static_cast<uint8_t>(ems) != 0;
   }
-  FMT_CONSTEXPR detail::color_type get_foreground() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_foreground() const noexcept {
     FMT_ASSERT(has_foreground(), "no foreground specified for this style");
     return foreground_color;
   }
-  FMT_CONSTEXPR detail::color_type get_background() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR detail::color_type get_background() const noexcept {
     FMT_ASSERT(has_background(), "no background specified for this style");
     return background_color;
   }
-  FMT_CONSTEXPR emphasis get_emphasis() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR emphasis get_emphasis() const noexcept {
     FMT_ASSERT(has_emphasis(), "no emphasis specified for this style");
     return ems;
   }
 
  private:
   FMT_CONSTEXPR text_style(bool is_foreground,
-                           detail::color_type text_color) FMT_NOEXCEPT
-      : set_foreground_color(),
-        set_background_color(),
-        ems() {
+                           detail::color_type text_color) noexcept
+      : set_foreground_color(), set_background_color(), ems() {
     if (is_foreground) {
       foreground_color = text_color;
       set_foreground_color = true;
@@ -320,36 +298,9 @@ class text_style {
     }
   }
 
-  // DEPRECATED!
-  FMT_CONSTEXPR text_style& and_assign(const text_style& rhs) {
-    if (!set_foreground_color) {
-      set_foreground_color = rhs.set_foreground_color;
-      foreground_color = rhs.foreground_color;
-    } else if (rhs.set_foreground_color) {
-      if (!foreground_color.is_rgb || !rhs.foreground_color.is_rgb)
-        FMT_THROW(format_error("can't AND a terminal color"));
-      foreground_color.value.rgb_color &= rhs.foreground_color.value.rgb_color;
-    }
+  friend FMT_CONSTEXPR text_style fg(detail::color_type foreground) noexcept;
 
-    if (!set_background_color) {
-      set_background_color = rhs.set_background_color;
-      background_color = rhs.background_color;
-    } else if (rhs.set_background_color) {
-      if (!background_color.is_rgb || !rhs.background_color.is_rgb)
-        FMT_THROW(format_error("can't AND a terminal color"));
-      background_color.value.rgb_color &= rhs.background_color.value.rgb_color;
-    }
-
-    ems = static_cast<emphasis>(static_cast<uint8_t>(ems) &
-                                static_cast<uint8_t>(rhs.ems));
-    return *this;
-  }
-
-  friend FMT_CONSTEXPR_DECL text_style fg(detail::color_type foreground)
-      FMT_NOEXCEPT;
-
-  friend FMT_CONSTEXPR_DECL text_style bg(detail::color_type background)
-      FMT_NOEXCEPT;
+  friend FMT_CONSTEXPR text_style bg(detail::color_type background) noexcept;
 
   detail::color_type foreground_color;
   detail::color_type background_color;
@@ -359,17 +310,16 @@ class text_style {
 };
 
 /** Creates a text style from the foreground (text) color. */
-FMT_CONSTEXPR inline text_style fg(detail::color_type foreground) FMT_NOEXCEPT {
+FMT_CONSTEXPR inline text_style fg(detail::color_type foreground) noexcept {
   return text_style(true, foreground);
 }
 
 /** Creates a text style from the background color. */
-FMT_CONSTEXPR inline text_style bg(detail::color_type background) FMT_NOEXCEPT {
+FMT_CONSTEXPR inline text_style bg(detail::color_type background) noexcept {
   return text_style(false, background);
 }
 
-FMT_CONSTEXPR inline text_style operator|(emphasis lhs,
-                                          emphasis rhs) FMT_NOEXCEPT {
+FMT_CONSTEXPR inline text_style operator|(emphasis lhs, emphasis rhs) noexcept {
   return text_style(lhs) | rhs;
 }
 
@@ -377,7 +327,7 @@ FMT_BEGIN_DETAIL_NAMESPACE
 
 template <typename Char> struct ansi_color_escape {
   FMT_CONSTEXPR ansi_color_escape(detail::color_type text_color,
-                                  const char* esc) FMT_NOEXCEPT {
+                                  const char* esc) noexcept {
     // If we have a terminal color, we need to output another escape code
     // sequence.
     if (!text_color.is_rgb) {
@@ -412,7 +362,7 @@ template <typename Char> struct ansi_color_escape {
     to_esc(color.b, buffer + 15, 'm');
     buffer[19] = static_cast<Char>(0);
   }
-  FMT_CONSTEXPR ansi_color_escape(emphasis em) FMT_NOEXCEPT {
+  FMT_CONSTEXPR ansi_color_escape(emphasis em) noexcept {
     uint8_t em_codes[num_emphases] = {};
     if (has_emphasis(em, emphasis::bold)) em_codes[0] = 1;
     if (has_emphasis(em, emphasis::faint)) em_codes[1] = 2;
@@ -433,10 +383,10 @@ template <typename Char> struct ansi_color_escape {
     }
     buffer[index++] = static_cast<Char>(0);
   }
-  FMT_CONSTEXPR operator const Char*() const FMT_NOEXCEPT { return buffer; }
+  FMT_CONSTEXPR operator const Char*() const noexcept { return buffer; }
 
-  FMT_CONSTEXPR const Char* begin() const FMT_NOEXCEPT { return buffer; }
-  FMT_CONSTEXPR_CHAR_TRAITS const Char* end() const FMT_NOEXCEPT {
+  FMT_CONSTEXPR const Char* begin() const noexcept { return buffer; }
+  FMT_CONSTEXPR_CHAR_TRAITS const Char* end() const noexcept {
     return buffer + std::char_traits<Char>::length(buffer);
   }
 
@@ -445,59 +395,44 @@ template <typename Char> struct ansi_color_escape {
   Char buffer[7u + 3u * num_emphases + 1u];
 
   static FMT_CONSTEXPR void to_esc(uint8_t c, Char* out,
-                                   char delimiter) FMT_NOEXCEPT {
+                                   char delimiter) noexcept {
     out[0] = static_cast<Char>('0' + c / 100);
     out[1] = static_cast<Char>('0' + c / 10 % 10);
     out[2] = static_cast<Char>('0' + c % 10);
     out[3] = static_cast<Char>(delimiter);
   }
-  static FMT_CONSTEXPR bool has_emphasis(emphasis em,
-                                         emphasis mask) FMT_NOEXCEPT {
+  static FMT_CONSTEXPR bool has_emphasis(emphasis em, emphasis mask) noexcept {
     return static_cast<uint8_t>(em) & static_cast<uint8_t>(mask);
   }
 };
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_foreground_color(
-    detail::color_type foreground) FMT_NOEXCEPT {
+    detail::color_type foreground) noexcept {
   return ansi_color_escape<Char>(foreground, "\x1b[38;2;");
 }
 
 template <typename Char>
 FMT_CONSTEXPR ansi_color_escape<Char> make_background_color(
-    detail::color_type background) FMT_NOEXCEPT {
+    detail::color_type background) noexcept {
   return ansi_color_escape<Char>(background, "\x1b[48;2;");
 }
 
 template <typename Char>
-FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) FMT_NOEXCEPT {
+FMT_CONSTEXPR ansi_color_escape<Char> make_emphasis(emphasis em) noexcept {
   return ansi_color_escape<Char>(em);
 }
 
-template <typename Char>
-inline void fputs(const Char* chars, FILE* stream) FMT_NOEXCEPT {
-  std::fputs(chars, stream);
-}
-
-template <>
-inline void fputs<wchar_t>(const wchar_t* chars, FILE* stream) FMT_NOEXCEPT {
-  std::fputws(chars, stream);
-}
-
-template <typename Char> inline void reset_color(FILE* stream) FMT_NOEXCEPT {
-  fputs("\x1b[0m", stream);
-}
-
-template <> inline void reset_color<wchar_t>(FILE* stream) FMT_NOEXCEPT {
-  fputs(L"\x1b[0m", stream);
-}
-
-template <typename Char>
-inline void reset_color(buffer<Char>& buffer) FMT_NOEXCEPT {
+template <typename Char> inline void reset_color(buffer<Char>& buffer) {
   auto reset_color = string_view("\x1b[0m");
   buffer.append(reset_color.begin(), reset_color.end());
 }
 
+template <typename T> struct styled_arg {
+  const T& value;
+  text_style style;
+};
+
 template <typename Char>
 void vformat_to(buffer<Char>& buf, const text_style& ts,
                 basic_string_view<Char> format_str,
@@ -524,13 +459,19 @@ void vformat_to(buffer<Char>& buf, const text_style& ts,
 
 FMT_END_DETAIL_NAMESPACE
 
-template <typename S, typename Char = char_t<S>>
-void vprint(std::FILE* f, const text_style& ts, const S& format,
-            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, to_string_view(format), args);
-  buf.push_back(Char(0));
-  detail::fputs(buf.data(), f);
+inline void vprint(std::FILE* f, const text_style& ts, string_view fmt,
+                   format_args args) {
+  // Legacy wide streams are not supported.
+  auto buf = memory_buffer();
+  detail::vformat_to(buf, ts, fmt, args);
+  if (detail::is_utf8()) {
+    detail::print(f, string_view(buf.begin(), buf.size()));
+    return;
+  }
+  buf.push_back('\0');
+  int result = std::fputs(buf.data(), f);
+  if (result < 0)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
 /**
@@ -549,7 +490,7 @@ template <typename S, typename... Args,
 void print(std::FILE* f, const text_style& ts, const S& format_str,
            const Args&... args) {
   vprint(f, ts, format_str,
-         fmt::make_args_checked<Args...>(format_str, args...));
+         fmt::make_format_args<buffer_context<char_t<S>>>(args...));
 }
 
 /**
@@ -574,7 +515,7 @@ inline std::basic_string<Char> vformat(
     const text_style& ts, const S& format_str,
     basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buf;
-  detail::vformat_to(buf, ts, to_string_view(format_str), args);
+  detail::vformat_to(buf, ts, detail::to_string_view(format_str), args);
   return fmt::to_string(buf);
 }
 
@@ -593,8 +534,8 @@ inline std::basic_string<Char> vformat(
 template <typename S, typename... Args, typename Char = char_t<S>>
 inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
                                       const Args&... args) {
-  return fmt::vformat(ts, to_string_view(format_str),
-                      fmt::make_args_checked<Args...>(format_str, args...));
+  return fmt::vformat(ts, detail::to_string_view(format_str),
+                      fmt::make_format_args<buffer_context<Char>>(args...));
 }
 
 /**
@@ -607,7 +548,7 @@ OutputIt vformat_to(
     basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   auto&& buf = detail::get_buffer<Char>(out);
   detail::vformat_to(buf, ts, format_str, args);
-  return detail::get_iterator(buf);
+  return detail::get_iterator(buf, out);
 }
 
 /**
@@ -628,11 +569,65 @@ template <typename OutputIt, typename S, typename... Args,
 inline auto format_to(OutputIt out, const text_style& ts, const S& format_str,
                       Args&&... args) ->
     typename std::enable_if<enable, OutputIt>::type {
-  return vformat_to(out, ts, to_string_view(format_str),
-                    fmt::make_args_checked<Args...>(format_str, args...));
+  return vformat_to(out, ts, detail::to_string_view(format_str),
+                    fmt::make_format_args<buffer_context<char_t<S>>>(args...));
+}
+
+template <typename T, typename Char>
+struct formatter<detail::styled_arg<T>, Char> : formatter<T, Char> {
+  template <typename FormatContext>
+  auto format(const detail::styled_arg<T>& arg, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    const auto& ts = arg.style;
+    const auto& value = arg.value;
+    auto out = ctx.out();
+
+    bool has_style = false;
+    if (ts.has_emphasis()) {
+      has_style = true;
+      auto emphasis = detail::make_emphasis<Char>(ts.get_emphasis());
+      out = std::copy(emphasis.begin(), emphasis.end(), out);
+    }
+    if (ts.has_foreground()) {
+      has_style = true;
+      auto foreground =
+          detail::make_foreground_color<Char>(ts.get_foreground());
+      out = std::copy(foreground.begin(), foreground.end(), out);
+    }
+    if (ts.has_background()) {
+      has_style = true;
+      auto background =
+          detail::make_background_color<Char>(ts.get_background());
+      out = std::copy(background.begin(), background.end(), out);
+    }
+    out = formatter<T, Char>::format(value, ctx);
+    if (has_style) {
+      auto reset_color = string_view("\x1b[0m");
+      out = std::copy(reset_color.begin(), reset_color.end(), out);
+    }
+    return out;
+  }
+};
+
+/**
+  \rst
+  Returns an argument that will be formatted using ANSI escape sequences,
+  to be used in a formatting function.
+
+  **Example**::
+
+    fmt::print("Elapsed time: {0:.2f} seconds",
+               fmt::styled(1.23, fmt::fg(fmt::color::green) |
+                                 fmt::bg(fmt::color::blue)));
+  \endrst
+ */
+template <typename T>
+FMT_CONSTEXPR auto styled(const T& value, text_style ts)
+    -> detail::styled_arg<remove_cvref_t<T>> {
+  return detail::styled_arg<remove_cvref_t<T>>{value, ts};
 }
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COLOR_H_
diff --git a/contrib/fmt/include/fmt/compile.h b/contrib/fmt/include/fmt/compile.h
index 1dba3ddb5..94e13c02d 100644
--- a/contrib/fmt/include/fmt/compile.h
+++ b/contrib/fmt/include/fmt/compile.h
@@ -13,48 +13,9 @@
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
-// An output iterator that counts the number of objects written to it and
-// discards them.
-class counting_iterator {
- private:
-  size_t count_;
-
- public:
-  using iterator_category = std::output_iterator_tag;
-  using difference_type = std::ptrdiff_t;
-  using pointer = void;
-  using reference = void;
-  using _Unchecked_type = counting_iterator;  // Mark iterator as checked.
-
-  struct value_type {
-    template <typename T> void operator=(const T&) {}
-  };
-
-  counting_iterator() : count_(0) {}
-
-  size_t count() const { return count_; }
-
-  counting_iterator& operator++() {
-    ++count_;
-    return *this;
-  }
-  counting_iterator operator++(int) {
-    auto it = *this;
-    ++*this;
-    return it;
-  }
-
-  friend counting_iterator operator+(counting_iterator it, difference_type n) {
-    it.count_ += static_cast<size_t>(n);
-    return it;
-  }
-
-  value_type operator*() const { return {}; }
-};
-
 template <typename Char, typename InputIt>
-inline counting_iterator copy_str(InputIt begin, InputIt end,
-                                  counting_iterator it) {
+FMT_CONSTEXPR inline counting_iterator copy_str(InputIt begin, InputIt end,
+                                                counting_iterator it) {
   return it + (end - begin);
 }
 
@@ -75,8 +36,7 @@ template <typename OutputIt> class truncating_iterator_base {
   using difference_type = std::ptrdiff_t;
   using pointer = void;
   using reference = void;
-  using _Unchecked_type =
-      truncating_iterator_base;  // Mark iterator as checked.
+  FMT_UNCHECKED_ITERATOR(truncating_iterator_base);
 
   OutputIt base() const { return out_; }
   size_t count() const { return count_; }
@@ -163,12 +123,12 @@ struct is_compiled_string : std::is_base_of<compiled_string, S> {};
 #  define FMT_COMPILE(s) FMT_STRING(s)
 #endif
 
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
 template <typename Char, size_t N,
           fmt::detail_exported::fixed_string<Char, N> Str>
 struct udl_compiled_string : compiled_string {
   using char_type = Char;
-  constexpr operator basic_string_view<char_type>() const {
+  explicit constexpr operator basic_string_view<char_type>() const {
     return {Str.data, N - 1};
   }
 };
@@ -371,38 +331,35 @@ template <typename T, typename Char> struct parse_specs_result {
   int next_arg_id;
 };
 
-constexpr int manual_indexing_id = -1;
+enum { manual_indexing_id = -1 };
 
 template <typename T, typename Char>
 constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
                                                   size_t pos, int next_arg_id) {
   str.remove_prefix(pos);
-  auto ctx = basic_format_parse_context<Char>(str, {}, next_arg_id);
+  auto ctx =
+      compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
   auto f = formatter<T, Char>();
   auto end = f.parse(ctx);
-  return {f, pos + fmt::detail::to_unsigned(end - str.data()) + 1,
+  return {f, pos + fmt::detail::to_unsigned(end - str.data()),
           next_arg_id == 0 ? manual_indexing_id : ctx.next_arg_id()};
 }
 
 template <typename Char> struct arg_id_handler {
   arg_ref<Char> arg_id;
 
-  constexpr int operator()() {
+  constexpr int on_auto() {
     FMT_ASSERT(false, "handler cannot be used with automatic indexing");
     return 0;
   }
-  constexpr int operator()(int id) {
+  constexpr int on_index(int id) {
     arg_id = arg_ref<Char>(id);
     return 0;
   }
-  constexpr int operator()(basic_string_view<Char> id) {
+  constexpr int on_name(basic_string_view<Char> id) {
     arg_id = arg_ref<Char>(id);
     return 0;
   }
-
-  constexpr void on_error(const char* message) {
-    FMT_THROW(format_error(message));
-  }
 };
 
 template <typename Char> struct parse_arg_id_result {
@@ -436,13 +393,20 @@ constexpr auto parse_replacement_field_then_tail(S format_str) {
     return parse_tail<Args, END_POS + 1, NEXT_ID>(
         field<char_type, typename field_type<T>::type, ARG_INDEX>(),
         format_str);
-  } else if constexpr (c == ':') {
+  } else if constexpr (c != ':') {
+    FMT_THROW(format_error("expected ':'"));
+  } else {
     constexpr auto result = parse_specs<typename field_type<T>::type>(
         str, END_POS + 1, NEXT_ID == manual_indexing_id ? 0 : NEXT_ID);
-    return parse_tail<Args, result.end, result.next_arg_id>(
-        spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
-            result.fmt},
-        format_str);
+    if constexpr (result.end >= str.size() || str[result.end] != '}') {
+      FMT_THROW(format_error("expected '}'"));
+      return 0;
+    } else {
+      return parse_tail<Args, result.end + 1, result.next_arg_id>(
+          spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
+              result.fmt},
+          format_str);
+    }
   }
 }
 
@@ -533,7 +497,7 @@ constexpr auto compile(S format_str) {
 #endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 
@@ -573,10 +537,11 @@ FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
   constexpr auto compiled = detail::compile<Args...>(S());
   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
                              detail::unknown_format>()) {
-    return format(static_cast<basic_string_view<typename S::char_type>>(S()),
-                  std::forward<Args>(args)...);
+    return fmt::format(
+        static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
   } else {
-    return format(compiled, std::forward<Args>(args)...);
+    return fmt::format(compiled, std::forward<Args>(args)...);
   }
 }
 
@@ -586,11 +551,11 @@ FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
   constexpr auto compiled = detail::compile<Args...>(S());
   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
                              detail::unknown_format>()) {
-    return format_to(out,
-                     static_cast<basic_string_view<typename S::char_type>>(S()),
-                     std::forward<Args>(args)...);
+    return fmt::format_to(
+        out, static_cast<basic_string_view<typename S::char_type>>(S()),
+        std::forward<Args>(args)...);
   } else {
-    return format_to(out, compiled, std::forward<Args>(args)...);
+    return fmt::format_to(out, compiled, std::forward<Args>(args)...);
   }
 }
 #endif
@@ -599,22 +564,24 @@ template <typename OutputIt, typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
                                          const S& format_str, Args&&... args) {
-  auto it = format_to(detail::truncating_iterator<OutputIt>(out, n), format_str,
-                      std::forward<Args>(args)...);
+  auto it = fmt::format_to(detail::truncating_iterator<OutputIt>(out, n),
+                           format_str, std::forward<Args>(args)...);
   return {it.base(), it.count()};
 }
 
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
-size_t formatted_size(const S& format_str, const Args&... args) {
-  return format_to(detail::counting_iterator(), format_str, args...).count();
+FMT_CONSTEXPR20 size_t formatted_size(const S& format_str,
+                                      const Args&... args) {
+  return fmt::format_to(detail::counting_iterator(), format_str, args...)
+      .count();
 }
 
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 void print(std::FILE* f, const S& format_str, const Args&... args) {
   memory_buffer buffer;
-  format_to(std::back_inserter(buffer), format_str, args...);
+  fmt::format_to(std::back_inserter(buffer), format_str, args...);
   detail::print(f, {buffer.data(), buffer.size()});
 }
 
@@ -624,19 +591,17 @@ void print(const S& format_str, const Args&... args) {
   print(stdout, format_str, args...);
 }
 
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
 inline namespace literals {
-template <detail_exported::fixed_string Str>
-constexpr detail::udl_compiled_string<
-    remove_cvref_t<decltype(Str.data[0])>,
-    sizeof(Str.data) / sizeof(decltype(Str.data[0])), Str>
-operator""_cf() {
-  return {};
+template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
+  using char_t = remove_cvref_t<decltype(Str.data[0])>;
+  return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
+                                     Str>();
 }
 }  // namespace literals
 #endif
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_COMPILE_H_
diff --git a/contrib/fmt/include/fmt/core.h b/contrib/fmt/include/fmt/core.h
index 92a7aa1df..46723d598 100644
--- a/contrib/fmt/include/fmt/core.h
+++ b/contrib/fmt/include/fmt/core.h
@@ -10,14 +10,14 @@
 
 #include <cstddef>  // std::byte
 #include <cstdio>   // std::FILE
-#include <cstring>
+#include <cstring>  // std::strlen
 #include <iterator>
 #include <limits>
 #include <string>
 #include <type_traits>
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
-#define FMT_VERSION 80101
+#define FMT_VERSION 100000
 
 #if defined(__clang__) && !defined(__ibmxl__)
 #  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
@@ -49,29 +49,27 @@
 #  define FMT_ICC_VERSION 0
 #endif
 
-#ifdef __NVCC__
-#  define FMT_NVCC __NVCC__
-#else
-#  define FMT_NVCC 0
-#endif
-
 #ifdef _MSC_VER
-#  define FMT_MSC_VER _MSC_VER
+#  define FMT_MSC_VERSION _MSC_VER
 #  define FMT_MSC_WARNING(...) __pragma(warning(__VA_ARGS__))
 #else
-#  define FMT_MSC_VER 0
+#  define FMT_MSC_VERSION 0
 #  define FMT_MSC_WARNING(...)
 #endif
 
+#ifdef _MSVC_LANG
+#  define FMT_CPLUSPLUS _MSVC_LANG
+#else
+#  define FMT_CPLUSPLUS __cplusplus
+#endif
+
 #ifdef __has_feature
 #  define FMT_HAS_FEATURE(x) __has_feature(x)
 #else
 #  define FMT_HAS_FEATURE(x) 0
 #endif
 
-#if defined(__has_include) &&                             \
-    (!defined(__INTELLISENSE__) || FMT_MSC_VER > 1900) && \
-    (!FMT_ICC_VERSION || FMT_ICC_VERSION >= 1600)
+#if defined(__has_include) || FMT_ICC_VERSION >= 1600 || FMT_MSC_VERSION > 1900
 #  define FMT_HAS_INCLUDE(x) __has_include(x)
 #else
 #  define FMT_HAS_INCLUDE(x) 0
@@ -83,12 +81,6 @@
 #  define FMT_HAS_CPP_ATTRIBUTE(x) 0
 #endif
 
-#ifdef _MSVC_LANG
-#  define FMT_CPLUSPLUS _MSVC_LANG
-#else
-#  define FMT_CPLUSPLUS __cplusplus
-#endif
-
 #define FMT_HAS_CPP14_ATTRIBUTE(attribute) \
   (FMT_CPLUSPLUS >= 201402L && FMT_HAS_CPP_ATTRIBUTE(attribute))
 
@@ -98,37 +90,38 @@
 // Check if relaxed C++14 constexpr is supported.
 // GCC doesn't allow throw in constexpr until version 6 (bug 67371).
 #ifndef FMT_USE_CONSTEXPR
-#  define FMT_USE_CONSTEXPR                                           \
-    (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VER >= 1912 || \
-     (FMT_GCC_VERSION >= 600 && __cplusplus >= 201402L)) &&           \
-        !FMT_NVCC && !FMT_ICC_VERSION
+#  if (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VERSION >= 1912 || \
+       (FMT_GCC_VERSION >= 600 && FMT_CPLUSPLUS >= 201402L)) &&             \
+      !FMT_ICC_VERSION && !defined(__NVCC__)
+#    define FMT_USE_CONSTEXPR 1
+#  else
+#    define FMT_USE_CONSTEXPR 0
+#  endif
 #endif
 #if FMT_USE_CONSTEXPR
 #  define FMT_CONSTEXPR constexpr
-#  define FMT_CONSTEXPR_DECL constexpr
 #else
 #  define FMT_CONSTEXPR
-#  define FMT_CONSTEXPR_DECL
 #endif
 
-#if ((__cplusplus >= 202002L) &&                              \
+#if ((FMT_CPLUSPLUS >= 202002L) &&                            \
      (!defined(_GLIBCXX_RELEASE) || _GLIBCXX_RELEASE > 9)) || \
-    (__cplusplus >= 201709L && FMT_GCC_VERSION >= 1002)
+    (FMT_CPLUSPLUS >= 201709L && FMT_GCC_VERSION >= 1002)
 #  define FMT_CONSTEXPR20 constexpr
 #else
 #  define FMT_CONSTEXPR20
 #endif
 
-// Check if constexpr std::char_traits<>::compare,length is supported.
+// Check if constexpr std::char_traits<>::{compare,length} are supported.
 #if defined(__GLIBCXX__)
-#  if __cplusplus >= 201703L && defined(_GLIBCXX_RELEASE) && \
+#  if FMT_CPLUSPLUS >= 201703L && defined(_GLIBCXX_RELEASE) && \
       _GLIBCXX_RELEASE >= 7  // GCC 7+ libstdc++ has _GLIBCXX_RELEASE.
 #    define FMT_CONSTEXPR_CHAR_TRAITS constexpr
 #  endif
-#elif defined(_LIBCPP_VERSION) && __cplusplus >= 201703L && \
+#elif defined(_LIBCPP_VERSION) && FMT_CPLUSPLUS >= 201703L && \
     _LIBCPP_VERSION >= 4000
 #  define FMT_CONSTEXPR_CHAR_TRAITS constexpr
-#elif FMT_MSC_VER >= 1914 && _MSVC_LANG >= 201703L
+#elif FMT_MSC_VERSION >= 1914 && FMT_CPLUSPLUS >= 201703L
 #  define FMT_CONSTEXPR_CHAR_TRAITS constexpr
 #endif
 #ifndef FMT_CONSTEXPR_CHAR_TRAITS
@@ -138,61 +131,21 @@
 // Check if exceptions are disabled.
 #ifndef FMT_EXCEPTIONS
 #  if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || \
-      FMT_MSC_VER && !_HAS_EXCEPTIONS
+      (FMT_MSC_VERSION && !_HAS_EXCEPTIONS)
 #    define FMT_EXCEPTIONS 0
 #  else
 #    define FMT_EXCEPTIONS 1
 #  endif
 #endif
 
-// Define FMT_USE_NOEXCEPT to make fmt use noexcept (C++11 feature).
-#ifndef FMT_USE_NOEXCEPT
-#  define FMT_USE_NOEXCEPT 0
-#endif
-
-#if FMT_USE_NOEXCEPT || FMT_HAS_FEATURE(cxx_noexcept) || \
-    FMT_GCC_VERSION >= 408 || FMT_MSC_VER >= 1900
-#  define FMT_DETECTED_NOEXCEPT noexcept
-#  define FMT_HAS_CXX11_NOEXCEPT 1
-#else
-#  define FMT_DETECTED_NOEXCEPT throw()
-#  define FMT_HAS_CXX11_NOEXCEPT 0
-#endif
-
-#ifndef FMT_NOEXCEPT
-#  if FMT_EXCEPTIONS || FMT_HAS_CXX11_NOEXCEPT
-#    define FMT_NOEXCEPT FMT_DETECTED_NOEXCEPT
-#  else
-#    define FMT_NOEXCEPT
-#  endif
-#endif
-
-// [[noreturn]] is disabled on MSVC and NVCC because of bogus unreachable code
-// warnings.
-#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VER && \
-    !FMT_NVCC
+// Disable [[noreturn]] on MSVC/NVCC because of bogus unreachable code warnings.
+#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VERSION && \
+    !defined(__NVCC__)
 #  define FMT_NORETURN [[noreturn]]
 #else
 #  define FMT_NORETURN
 #endif
 
-#if __cplusplus == 201103L || __cplusplus == 201402L
-#  if defined(__INTEL_COMPILER) || defined(__PGI)
-#    define FMT_FALLTHROUGH
-#  elif defined(__clang__)
-#    define FMT_FALLTHROUGH [[clang::fallthrough]]
-#  elif FMT_GCC_VERSION >= 700 && \
-      (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 520)
-#    define FMT_FALLTHROUGH [[gnu::fallthrough]]
-#  else
-#    define FMT_FALLTHROUGH
-#  endif
-#elif FMT_HAS_CPP17_ATTRIBUTE(fallthrough)
-#  define FMT_FALLTHROUGH [[fallthrough]]
-#else
-#  define FMT_FALLTHROUGH
-#endif
-
 #ifndef FMT_NODISCARD
 #  if FMT_HAS_CPP17_ATTRIBUTE(nodiscard)
 #    define FMT_NODISCARD [[nodiscard]]
@@ -201,16 +154,6 @@
 #  endif
 #endif
 
-#ifndef FMT_USE_FLOAT
-#  define FMT_USE_FLOAT 1
-#endif
-#ifndef FMT_USE_DOUBLE
-#  define FMT_USE_DOUBLE 1
-#endif
-#ifndef FMT_USE_LONG_DOUBLE
-#  define FMT_USE_LONG_DOUBLE 1
-#endif
-
 #ifndef FMT_INLINE
 #  if FMT_GCC_VERSION || FMT_CLANG_VERSION
 #    define FMT_INLINE inline __attribute__((always_inline))
@@ -219,24 +162,20 @@
 #  endif
 #endif
 
-#ifndef FMT_DEPRECATED
-#  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VER >= 1900
-#    define FMT_DEPRECATED [[deprecated]]
-#  else
-#    if (defined(__GNUC__) && !defined(__LCC__)) || defined(__clang__)
-#      define FMT_DEPRECATED __attribute__((deprecated))
-#    elif FMT_MSC_VER
-#      define FMT_DEPRECATED __declspec(deprecated)
-#    else
-#      define FMT_DEPRECATED /* deprecated */
-#    endif
-#  endif
+// An inline std::forward replacement.
+#define FMT_FORWARD(...) static_cast<decltype(__VA_ARGS__)&&>(__VA_ARGS__)
+
+#ifdef _MSC_VER
+#  define FMT_UNCHECKED_ITERATOR(It) \
+    using _Unchecked_type = It  // Mark iterator as checked.
+#else
+#  define FMT_UNCHECKED_ITERATOR(It) using unchecked_type = It
 #endif
 
 #ifndef FMT_BEGIN_NAMESPACE
 #  define FMT_BEGIN_NAMESPACE \
     namespace fmt {           \
-    inline namespace v8 {
+    inline namespace v10 {
 #  define FMT_END_NAMESPACE \
     }                       \
     }
@@ -244,22 +183,18 @@
 
 #ifndef FMT_MODULE_EXPORT
 #  define FMT_MODULE_EXPORT
-#  define FMT_MODULE_EXPORT_BEGIN
-#  define FMT_MODULE_EXPORT_END
-#  define FMT_BEGIN_DETAIL_NAMESPACE namespace detail {
-#  define FMT_END_DETAIL_NAMESPACE }
+#  define FMT_BEGIN_EXPORT
+#  define FMT_END_EXPORT
 #endif
 
 #if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
-#  define FMT_CLASS_API FMT_MSC_WARNING(suppress : 4275)
-#  ifdef FMT_EXPORT
+#  ifdef FMT_LIB_EXPORT
 #    define FMT_API __declspec(dllexport)
 #  elif defined(FMT_SHARED)
 #    define FMT_API __declspec(dllimport)
 #  endif
 #else
-#  define FMT_CLASS_API
-#  if defined(FMT_EXPORT) || defined(FMT_SHARED)
+#  if defined(FMT_LIB_EXPORT) || defined(FMT_SHARED)
 #    if defined(__GNUC__) || defined(__clang__)
 #      define FMT_API __attribute__((visibility("default")))
 #    endif
@@ -270,26 +205,27 @@
 #endif
 
 // libc++ supports string_view in pre-c++17.
-#if (FMT_HAS_INCLUDE(<string_view>) &&                       \
-     (__cplusplus > 201402L || defined(_LIBCPP_VERSION))) || \
-    (defined(_MSVC_LANG) && _MSVC_LANG > 201402L && _MSC_VER >= 1910)
+#if FMT_HAS_INCLUDE(<string_view>) && \
+    (FMT_CPLUSPLUS >= 201703L || defined(_LIBCPP_VERSION))
 #  include <string_view>
 #  define FMT_USE_STRING_VIEW
-#elif FMT_HAS_INCLUDE("experimental/string_view") && __cplusplus >= 201402L
+#elif FMT_HAS_INCLUDE("experimental/string_view") && FMT_CPLUSPLUS >= 201402L
 #  include <experimental/string_view>
 #  define FMT_USE_EXPERIMENTAL_STRING_VIEW
 #endif
 
 #ifndef FMT_UNICODE
-#  define FMT_UNICODE !FMT_MSC_VER
+#  define FMT_UNICODE !FMT_MSC_VERSION
 #endif
 
 #ifndef FMT_CONSTEVAL
-#  if ((FMT_GCC_VERSION >= 1000 || FMT_CLANG_VERSION >= 1101) &&      \
-       __cplusplus > 201703L && !defined(__apple_build_version__)) || \
-      (defined(__cpp_consteval) &&                                    \
-       (!FMT_MSC_VER || _MSC_FULL_VER >= 193030704))
-// consteval is broken in MSVC before VS2022 and Apple clang 13.
+#  if ((FMT_GCC_VERSION >= 1000 || FMT_CLANG_VERSION >= 1101) && \
+       (!defined(__apple_build_version__) ||                     \
+        __apple_build_version__ >= 14000029L) &&                 \
+       FMT_CPLUSPLUS >= 202002L) ||                              \
+      (defined(__cpp_consteval) &&                               \
+       (!FMT_MSC_VERSION || _MSC_FULL_VER >= 193030704))
+// consteval is broken in MSVC before VS2022 and Apple clang before 14.
 #    define FMT_CONSTEVAL consteval
 #    define FMT_HAS_CONSTEVAL
 #  else
@@ -297,24 +233,31 @@
 #  endif
 #endif
 
-#ifndef FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
-#  if defined(__cpp_nontype_template_args) &&                \
-      ((FMT_GCC_VERSION >= 903 && __cplusplus >= 201709L) || \
-       __cpp_nontype_template_args >= 201911L)
-#    define FMT_USE_NONTYPE_TEMPLATE_PARAMETERS 1
+#ifndef FMT_USE_NONTYPE_TEMPLATE_ARGS
+#  if defined(__cpp_nontype_template_args) &&                  \
+      ((FMT_GCC_VERSION >= 903 && FMT_CPLUSPLUS >= 201709L) || \
+       __cpp_nontype_template_args >= 201911L) &&              \
+      !defined(__NVCOMPILER) && !defined(__LCC__)
+#    define FMT_USE_NONTYPE_TEMPLATE_ARGS 1
 #  else
-#    define FMT_USE_NONTYPE_TEMPLATE_PARAMETERS 0
+#    define FMT_USE_NONTYPE_TEMPLATE_ARGS 0
 #  endif
 #endif
 
+#if defined __cpp_inline_variables && __cpp_inline_variables >= 201606L
+#  define FMT_INLINE_VARIABLE inline
+#else
+#  define FMT_INLINE_VARIABLE
+#endif
+
 // Enable minimal optimizations for more compact code in debug mode.
 FMT_GCC_PRAGMA("GCC push_options")
-#ifndef __OPTIMIZE__
+#if !defined(__OPTIMIZE__) && !defined(__NVCOMPILER) && !defined(__LCC__) && \
+    !defined(__CUDACC__)
 FMT_GCC_PRAGMA("GCC optimize(\"Og\")")
 #endif
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
 
 // Implementations of enable_if_t and other metafunctions for older systems.
 template <bool B, typename T = void>
@@ -330,6 +273,8 @@ template <typename T>
 using remove_cvref_t = typename std::remove_cv<remove_reference_t<T>>::type;
 template <typename T> struct type_identity { using type = T; };
 template <typename T> using type_identity_t = typename type_identity<T>::type;
+template <typename T>
+using underlying_t = typename std::underlying_type<T>::type;
 
 struct monostate {
   constexpr monostate() {}
@@ -341,19 +286,32 @@ struct monostate {
 #ifdef FMT_DOC
 #  define FMT_ENABLE_IF(...)
 #else
-#  define FMT_ENABLE_IF(...) enable_if_t<(__VA_ARGS__), int> = 0
+#  define FMT_ENABLE_IF(...) fmt::enable_if_t<(__VA_ARGS__), int> = 0
 #endif
 
-FMT_BEGIN_DETAIL_NAMESPACE
+#ifdef __cpp_lib_byte
+inline auto format_as(std::byte b) -> unsigned char {
+  return static_cast<unsigned char>(b);
+}
+#endif
 
-// Suppress "unused variable" warnings with the method described in
+namespace detail {
+// Suppresses "unused variable" warnings with the method described in
 // https://herbsutter.com/2009/10/18/mailbag-shutting-up-compiler-warnings/.
 // (void)var does not work on many Intel compilers.
 template <typename... T> FMT_CONSTEXPR void ignore_unused(const T&...) {}
 
-constexpr FMT_INLINE auto is_constant_evaluated(bool default_value = false)
-    FMT_NOEXCEPT -> bool {
-#ifdef __cpp_lib_is_constant_evaluated
+constexpr FMT_INLINE auto is_constant_evaluated(
+    bool default_value = false) noexcept -> bool {
+// Workaround for incompatibility between libstdc++ consteval-based
+// std::is_constant_evaluated() implementation and clang-14.
+// https://github.com/fmtlib/fmt/issues/3247
+#if FMT_CPLUSPLUS >= 202002L && defined(_GLIBCXX_RELEASE) && \
+    _GLIBCXX_RELEASE >= 12 &&                                \
+    (FMT_CLANG_VERSION >= 1400 && FMT_CLANG_VERSION < 1500)
+  ignore_unused(default_value);
+  return __builtin_is_constant_evaluated();
+#elif defined(__cpp_lib_is_constant_evaluated)
   ignore_unused(default_value);
   return std::is_constant_evaluated();
 #else
@@ -361,7 +319,7 @@ constexpr FMT_INLINE auto is_constant_evaluated(bool default_value = false)
 #endif
 }
 
-// A function to suppress "conditional expression is constant" warnings.
+// Suppresses "conditional expression is constant" warnings.
 template <typename T> constexpr FMT_INLINE auto const_check(T value) -> T {
   return value;
 }
@@ -371,23 +329,17 @@ FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
 
 #ifndef FMT_ASSERT
 #  ifdef NDEBUG
-// FMT_ASSERT is not empty to avoid -Werror=empty-body.
+// FMT_ASSERT is not empty to avoid -Wempty-body.
 #    define FMT_ASSERT(condition, message) \
-      ::fmt::detail::ignore_unused((condition), (message))
+      fmt::detail::ignore_unused((condition), (message))
 #  else
 #    define FMT_ASSERT(condition, message)                                    \
       ((condition) /* void() fails with -Winvalid-constexpr on clang 4.0.1 */ \
            ? (void)0                                                          \
-           : ::fmt::detail::assert_fail(__FILE__, __LINE__, (message)))
+           : fmt::detail::assert_fail(__FILE__, __LINE__, (message)))
 #  endif
 #endif
 
-#ifdef __cpp_lib_byte
-using byte = std::byte;
-#else
-enum class byte : unsigned char {};
-#endif
-
 #if defined(FMT_USE_STRING_VIEW)
 template <typename Char> using std_string_view = std::basic_string_view<Char>;
 #elif defined(FMT_USE_EXPERIMENTAL_STRING_VIEW)
@@ -399,11 +351,11 @@ template <typename T> struct std_string_view {};
 
 #ifdef FMT_USE_INT128
 // Do nothing.
-#elif defined(__SIZEOF_INT128__) && !FMT_NVCC && \
-    !(FMT_CLANG_VERSION && FMT_MSC_VER)
+#elif defined(__SIZEOF_INT128__) && !defined(__NVCC__) && \
+    !(FMT_CLANG_VERSION && FMT_MSC_VERSION)
 #  define FMT_USE_INT128 1
-using int128_t = __int128_t;
-using uint128_t = __uint128_t;
+using int128_opt = __int128_t;  // An optional native 128-bit integer.
+using uint128_opt = __uint128_t;
 template <typename T> inline auto convert_for_visit(T value) -> T {
   return value;
 }
@@ -411,32 +363,29 @@ template <typename T> inline auto convert_for_visit(T value) -> T {
 #  define FMT_USE_INT128 0
 #endif
 #if !FMT_USE_INT128
-enum class int128_t {};
-enum class uint128_t {};
+enum class int128_opt {};
+enum class uint128_opt {};
 // Reduce template instantiations.
-template <typename T> inline auto convert_for_visit(T) -> monostate {
-  return {};
-}
+template <typename T> auto convert_for_visit(T) -> monostate { return {}; }
 #endif
 
 // Casts a nonnegative integer to unsigned.
 template <typename Int>
 FMT_CONSTEXPR auto to_unsigned(Int value) ->
     typename std::make_unsigned<Int>::type {
-  FMT_ASSERT(value >= 0, "negative value");
+  FMT_ASSERT(std::is_unsigned<Int>::value || value >= 0, "negative value");
   return static_cast<typename std::make_unsigned<Int>::type>(value);
 }
 
-FMT_MSC_WARNING(suppress : 4566) constexpr unsigned char micro[] = "\u00B5";
+FMT_CONSTEXPR inline auto is_utf8() -> bool {
+  FMT_MSC_WARNING(suppress : 4566) constexpr unsigned char section[] = "\u00A7";
 
-constexpr auto is_utf8() -> bool {
-  // Avoid buggy sign extensions in MSVC's constant evaluation mode.
-  // https://developercommunity.visualstudio.com/t/C-difference-in-behavior-for-unsigned/1233612
+  // Avoid buggy sign extensions in MSVC's constant evaluation mode (#2297).
   using uchar = unsigned char;
-  return FMT_UNICODE || (sizeof(micro) == 3 && uchar(micro[0]) == 0xC2 &&
-                         uchar(micro[1]) == 0xB5);
+  return FMT_UNICODE || (sizeof(section) == 3 && uchar(section[0]) == 0xC2 &&
+                         uchar(section[1]) == 0xA7);
 }
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
 
 /**
   An implementation of ``std::basic_string_view`` for pre-C++17. It provides a
@@ -445,6 +394,7 @@ FMT_END_DETAIL_NAMESPACE
   compiled with a different ``-std`` option than the client code (which is not
   recommended).
  */
+FMT_MODULE_EXPORT
 template <typename Char> class basic_string_view {
  private:
   const Char* data_;
@@ -454,12 +404,11 @@ template <typename Char> class basic_string_view {
   using value_type = Char;
   using iterator = const Char*;
 
-  constexpr basic_string_view() FMT_NOEXCEPT : data_(nullptr), size_(0) {}
+  constexpr basic_string_view() noexcept : data_(nullptr), size_(0) {}
 
   /** Constructs a string reference object from a C string and a size. */
-  constexpr basic_string_view(const Char* s, size_t count) FMT_NOEXCEPT
-      : data_(s),
-        size_(count) {}
+  constexpr basic_string_view(const Char* s, size_t count) noexcept
+      : data_(s), size_(count) {}
 
   /**
     \rst
@@ -479,33 +428,44 @@ template <typename Char> class basic_string_view {
   /** Constructs a string reference from a ``std::basic_string`` object. */
   template <typename Traits, typename Alloc>
   FMT_CONSTEXPR basic_string_view(
-      const std::basic_string<Char, Traits, Alloc>& s) FMT_NOEXCEPT
-      : data_(s.data()),
-        size_(s.size()) {}
+      const std::basic_string<Char, Traits, Alloc>& s) noexcept
+      : data_(s.data()), size_(s.size()) {}
 
   template <typename S, FMT_ENABLE_IF(std::is_same<
                                       S, detail::std_string_view<Char>>::value)>
-  FMT_CONSTEXPR basic_string_view(S s) FMT_NOEXCEPT : data_(s.data()),
-                                                      size_(s.size()) {}
+  FMT_CONSTEXPR basic_string_view(S s) noexcept
+      : data_(s.data()), size_(s.size()) {}
 
   /** Returns a pointer to the string data. */
-  constexpr auto data() const FMT_NOEXCEPT -> const Char* { return data_; }
+  constexpr auto data() const noexcept -> const Char* { return data_; }
 
   /** Returns the string size. */
-  constexpr auto size() const FMT_NOEXCEPT -> size_t { return size_; }
+  constexpr auto size() const noexcept -> size_t { return size_; }
 
-  constexpr auto begin() const FMT_NOEXCEPT -> iterator { return data_; }
-  constexpr auto end() const FMT_NOEXCEPT -> iterator { return data_ + size_; }
+  constexpr auto begin() const noexcept -> iterator { return data_; }
+  constexpr auto end() const noexcept -> iterator { return data_ + size_; }
 
-  constexpr auto operator[](size_t pos) const FMT_NOEXCEPT -> const Char& {
+  constexpr auto operator[](size_t pos) const noexcept -> const Char& {
     return data_[pos];
   }
 
-  FMT_CONSTEXPR void remove_prefix(size_t n) FMT_NOEXCEPT {
+  FMT_CONSTEXPR void remove_prefix(size_t n) noexcept {
     data_ += n;
     size_ -= n;
   }
 
+  FMT_CONSTEXPR_CHAR_TRAITS bool starts_with(
+      basic_string_view<Char> sv) const noexcept {
+    return size_ >= sv.size_ &&
+           std::char_traits<Char>::compare(data_, sv.data_, sv.size_) == 0;
+  }
+  FMT_CONSTEXPR_CHAR_TRAITS bool starts_with(Char c) const noexcept {
+    return size_ >= 1 && std::char_traits<Char>::eq(*data_, c);
+  }
+  FMT_CONSTEXPR_CHAR_TRAITS bool starts_with(const Char* s) const {
+    return starts_with(basic_string_view<Char>(s));
+  }
+
   // Lexicographically compare this string reference to other.
   FMT_CONSTEXPR_CHAR_TRAITS auto compare(basic_string_view other) const -> int {
     size_t str_size = size_ < other.size_ ? size_ : other.size_;
@@ -537,13 +497,22 @@ template <typename Char> class basic_string_view {
   }
 };
 
+FMT_MODULE_EXPORT
 using string_view = basic_string_view<char>;
 
 /** Specifies if ``T`` is a character type. Can be specialized by users. */
+FMT_MODULE_EXPORT
 template <typename T> struct is_char : std::false_type {};
 template <> struct is_char<char> : std::true_type {};
 
-// Returns a string view of `s`.
+namespace detail {
+
+// A base class for compile-time strings.
+struct compile_string {};
+
+template <typename S>
+struct is_compile_string : std::is_base_of<compile_string, S> {};
+
 template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
 FMT_INLINE auto to_string_view(const Char* s) -> basic_string_view<Char> {
   return s;
@@ -559,36 +528,24 @@ constexpr auto to_string_view(basic_string_view<Char> s)
   return s;
 }
 template <typename Char,
-          FMT_ENABLE_IF(!std::is_empty<detail::std_string_view<Char>>::value)>
-inline auto to_string_view(detail::std_string_view<Char> s)
-    -> basic_string_view<Char> {
+          FMT_ENABLE_IF(!std::is_empty<std_string_view<Char>>::value)>
+inline auto to_string_view(std_string_view<Char> s) -> basic_string_view<Char> {
   return s;
 }
-
-// A base class for compile-time strings. It is defined in the fmt namespace to
-// make formatting functions visible via ADL, e.g. format(FMT_STRING("{}"), 42).
-struct compile_string {};
-
-template <typename S>
-struct is_compile_string : std::is_base_of<compile_string, S> {};
-
 template <typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
 constexpr auto to_string_view(const S& s)
     -> basic_string_view<typename S::char_type> {
   return basic_string_view<typename S::char_type>(s);
 }
-
-FMT_BEGIN_DETAIL_NAMESPACE
-
 void to_string_view(...);
-using fmt::to_string_view;
 
 // Specifies whether S is a string type convertible to fmt::basic_string_view.
 // It should be a constexpr function but MSVC 2017 fails to compile it in
 // enable_if and MSVC 2015 fails to compile it as an alias template.
+// ADL is intentionally disabled as to_string_view is not an extension point.
 template <typename S>
-struct is_string : std::is_class<decltype(to_string_view(std::declval<S>()))> {
-};
+struct is_string
+    : std::is_class<decltype(detail::to_string_view(std::declval<S>()))> {};
 
 template <typename S, typename = void> struct char_t_impl {};
 template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
@@ -596,28 +553,91 @@ template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
   using type = typename result::value_type;
 };
 
-// Reports a compile-time error if S is not a valid format string.
-template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
-FMT_INLINE void check_format_string(const S&) {
-#ifdef FMT_ENFORCE_COMPILE_STRING
-  static_assert(is_compile_string<S>::value,
-                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
-                "FMT_STRING.");
-#endif
+enum class type {
+  none_type,
+  // Integer types should go first,
+  int_type,
+  uint_type,
+  long_long_type,
+  ulong_long_type,
+  int128_type,
+  uint128_type,
+  bool_type,
+  char_type,
+  last_integer_type = char_type,
+  // followed by floating-point types.
+  float_type,
+  double_type,
+  long_double_type,
+  last_numeric_type = long_double_type,
+  cstring_type,
+  string_type,
+  pointer_type,
+  custom_type
+};
+
+// Maps core type T to the corresponding type enum constant.
+template <typename T, typename Char>
+struct type_constant : std::integral_constant<type, type::custom_type> {};
+
+#define FMT_TYPE_CONSTANT(Type, constant) \
+  template <typename Char>                \
+  struct type_constant<Type, Char>        \
+      : std::integral_constant<type, type::constant> {}
+
+FMT_TYPE_CONSTANT(int, int_type);
+FMT_TYPE_CONSTANT(unsigned, uint_type);
+FMT_TYPE_CONSTANT(long long, long_long_type);
+FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
+FMT_TYPE_CONSTANT(int128_opt, int128_type);
+FMT_TYPE_CONSTANT(uint128_opt, uint128_type);
+FMT_TYPE_CONSTANT(bool, bool_type);
+FMT_TYPE_CONSTANT(Char, char_type);
+FMT_TYPE_CONSTANT(float, float_type);
+FMT_TYPE_CONSTANT(double, double_type);
+FMT_TYPE_CONSTANT(long double, long_double_type);
+FMT_TYPE_CONSTANT(const Char*, cstring_type);
+FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
+FMT_TYPE_CONSTANT(const void*, pointer_type);
+
+constexpr bool is_integral_type(type t) {
+  return t > type::none_type && t <= type::last_integer_type;
+}
+constexpr bool is_arithmetic_type(type t) {
+  return t > type::none_type && t <= type::last_numeric_type;
 }
-template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
-void check_format_string(S);
+
+constexpr auto set(type rhs) -> int { return 1 << static_cast<int>(rhs); }
+constexpr auto in(type t, int set) -> bool {
+  return ((set >> static_cast<int>(t)) & 1) != 0;
+}
+
+// Bitsets of types.
+enum {
+  sint_set =
+      set(type::int_type) | set(type::long_long_type) | set(type::int128_type),
+  uint_set = set(type::uint_type) | set(type::ulong_long_type) |
+             set(type::uint128_type),
+  bool_set = set(type::bool_type),
+  char_set = set(type::char_type),
+  float_set = set(type::float_type) | set(type::double_type) |
+              set(type::long_double_type),
+  string_set = set(type::string_type),
+  cstring_set = set(type::cstring_type),
+  pointer_set = set(type::pointer_type)
+};
 
 FMT_NORETURN FMT_API void throw_format_error(const char* message);
 
 struct error_handler {
   constexpr error_handler() = default;
-  constexpr error_handler(const error_handler&) = default;
 
   // This function is intentionally not constexpr to give a compile-time error.
-  FMT_NORETURN FMT_API void on_error(const char* message);
+  FMT_NORETURN void on_error(const char* message) {
+    throw_format_error(message);
+  }
 };
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
 
 /** String's character type. */
 template <typename S> using char_t = typename detail::char_t_impl<S>::type;
@@ -629,35 +649,34 @@ template <typename S> using char_t = typename detail::char_t_impl<S>::type;
   You can use the ``format_parse_context`` type alias for ``char`` instead.
   \endrst
  */
-template <typename Char, typename ErrorHandler = detail::error_handler>
-class basic_format_parse_context : private ErrorHandler {
+FMT_MODULE_EXPORT
+template <typename Char> class basic_format_parse_context {
  private:
   basic_string_view<Char> format_str_;
   int next_arg_id_;
 
+  FMT_CONSTEXPR void do_check_arg_id(int id);
+
  public:
   using char_type = Char;
-  using iterator = typename basic_string_view<Char>::iterator;
+  using iterator = const Char*;
 
   explicit constexpr basic_format_parse_context(
-      basic_string_view<Char> format_str, ErrorHandler eh = {},
-      int next_arg_id = 0)
-      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(next_arg_id) {}
+      basic_string_view<Char> format_str, int next_arg_id = 0)
+      : format_str_(format_str), next_arg_id_(next_arg_id) {}
 
   /**
     Returns an iterator to the beginning of the format string range being
     parsed.
    */
-  constexpr auto begin() const FMT_NOEXCEPT -> iterator {
+  constexpr auto begin() const noexcept -> iterator {
     return format_str_.begin();
   }
 
   /**
     Returns an iterator past the end of the format string range being parsed.
    */
-  constexpr auto end() const FMT_NOEXCEPT -> iterator {
-    return format_str_.end();
-  }
+  constexpr auto end() const noexcept -> iterator { return format_str_.end(); }
 
   /** Advances the begin iterator to ``it``. */
   FMT_CONSTEXPR void advance_to(iterator it) {
@@ -669,40 +688,104 @@ class basic_format_parse_context : private ErrorHandler {
     the next argument index and switches to the automatic indexing.
    */
   FMT_CONSTEXPR auto next_arg_id() -> int {
-    // Don't check if the argument id is valid to avoid overhead and because it
-    // will be checked during formatting anyway.
-    if (next_arg_id_ >= 0) return next_arg_id_++;
-    on_error("cannot switch from manual to automatic argument indexing");
-    return 0;
+    if (next_arg_id_ < 0) {
+      detail::throw_format_error(
+          "cannot switch from manual to automatic argument indexing");
+      return 0;
+    }
+    int id = next_arg_id_++;
+    do_check_arg_id(id);
+    return id;
   }
 
   /**
     Reports an error if using the automatic argument indexing; otherwise
     switches to the manual indexing.
    */
-  FMT_CONSTEXPR void check_arg_id(int) {
-    if (next_arg_id_ > 0)
-      on_error("cannot switch from automatic to manual argument indexing");
-    else
-      next_arg_id_ = -1;
+  FMT_CONSTEXPR void check_arg_id(int id) {
+    if (next_arg_id_ > 0) {
+      detail::throw_format_error(
+          "cannot switch from automatic to manual argument indexing");
+      return;
+    }
+    next_arg_id_ = -1;
+    do_check_arg_id(id);
   }
-
   FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {}
+  FMT_CONSTEXPR void check_dynamic_spec(int arg_id);
+};
 
-  FMT_CONSTEXPR void on_error(const char* message) {
-    ErrorHandler::on_error(message);
+FMT_MODULE_EXPORT
+using format_parse_context = basic_format_parse_context<char>;
+
+namespace detail {
+// A parse context with extra data used only in compile-time checks.
+template <typename Char>
+class compile_parse_context : public basic_format_parse_context<Char> {
+ private:
+  int num_args_;
+  const type* types_;
+  using base = basic_format_parse_context<Char>;
+
+ public:
+  explicit FMT_CONSTEXPR compile_parse_context(
+      basic_string_view<Char> format_str, int num_args, const type* types,
+      int next_arg_id = 0)
+      : base(format_str, next_arg_id), num_args_(num_args), types_(types) {}
+
+  constexpr auto num_args() const -> int { return num_args_; }
+  constexpr auto arg_type(int id) const -> type { return types_[id]; }
+
+  FMT_CONSTEXPR auto next_arg_id() -> int {
+    int id = base::next_arg_id();
+    if (id >= num_args_) throw_format_error("argument not found");
+    return id;
   }
 
-  constexpr auto error_handler() const -> ErrorHandler { return *this; }
+  FMT_CONSTEXPR void check_arg_id(int id) {
+    base::check_arg_id(id);
+    if (id >= num_args_) throw_format_error("argument not found");
+  }
+  using base::check_arg_id;
+
+  FMT_CONSTEXPR void check_dynamic_spec(int arg_id) {
+    detail::ignore_unused(arg_id);
+#if !defined(__LCC__)
+    if (arg_id < num_args_ && types_ && !is_integral_type(types_[arg_id]))
+      throw_format_error("width/precision is not integer");
+#endif
+  }
 };
+}  // namespace detail
 
-using format_parse_context = basic_format_parse_context<char>;
+template <typename Char>
+FMT_CONSTEXPR void basic_format_parse_context<Char>::do_check_arg_id(int id) {
+  // Argument id is only checked at compile-time during parsing because
+  // formatting has its own validation.
+  if (detail::is_constant_evaluated() &&
+      (!FMT_GCC_VERSION || FMT_GCC_VERSION >= 1200)) {
+    using context = detail::compile_parse_context<Char>;
+    if (id >= static_cast<context*>(this)->num_args())
+      detail::throw_format_error("argument not found");
+  }
+}
 
-template <typename Context> class basic_format_arg;
-template <typename Context> class basic_format_args;
-template <typename Context> class dynamic_format_arg_store;
+template <typename Char>
+FMT_CONSTEXPR void basic_format_parse_context<Char>::check_dynamic_spec(
+    int arg_id) {
+  if (detail::is_constant_evaluated() &&
+      (!FMT_GCC_VERSION || FMT_GCC_VERSION >= 1200)) {
+    using context = detail::compile_parse_context<Char>;
+    static_cast<context*>(this)->check_dynamic_spec(arg_id);
+  }
+}
+
+FMT_MODULE_EXPORT template <typename Context> class basic_format_arg;
+FMT_MODULE_EXPORT template <typename Context> class basic_format_args;
+FMT_MODULE_EXPORT template <typename Context> class dynamic_format_arg_store;
 
 // A formatter for objects of type T.
+FMT_MODULE_EXPORT
 template <typename T, typename Char = char, typename Enable = void>
 struct formatter {
   // A deleted default constructor indicates a disabled formatter.
@@ -722,7 +805,7 @@ struct is_contiguous<std::basic_string<Char>> : std::true_type {};
 
 class appender;
 
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
 
 template <typename Context, typename T>
 constexpr auto has_const_formatter_impl(T*)
@@ -744,10 +827,10 @@ constexpr auto has_const_formatter() -> bool {
 template <typename Container>
 inline auto get_container(std::back_insert_iterator<Container> it)
     -> Container& {
-  using bi_iterator = std::back_insert_iterator<Container>;
-  struct accessor : bi_iterator {
-    accessor(bi_iterator iter) : bi_iterator(iter) {}
-    using bi_iterator::container;
+  using base = std::back_insert_iterator<Container>;
+  struct accessor : base {
+    accessor(base b) : base(b) {}
+    using base::container;
   };
   return *accessor(it).container;
 }
@@ -765,7 +848,7 @@ template <typename Char, typename T, typename U,
 FMT_CONSTEXPR auto copy_str(T* begin, T* end, U* out) -> U* {
   if (is_constant_evaluated()) return copy_str<Char, T*, U*>(begin, end, out);
   auto size = to_unsigned(end - begin);
-  memcpy(out, begin, size * sizeof(U));
+  if (size > 0) memcpy(out, begin, size * sizeof(U));
   return out + size;
 }
 
@@ -784,18 +867,16 @@ template <typename T> class buffer {
  protected:
   // Don't initialize ptr_ since it is not accessed to save a few cycles.
   FMT_MSC_WARNING(suppress : 26495)
-  buffer(size_t sz) FMT_NOEXCEPT : size_(sz), capacity_(sz) {}
+  buffer(size_t sz) noexcept : size_(sz), capacity_(sz) {}
 
-  FMT_CONSTEXPR20 buffer(T* p = nullptr, size_t sz = 0,
-                         size_t cap = 0) FMT_NOEXCEPT : ptr_(p),
-                                                        size_(sz),
-                                                        capacity_(cap) {}
+  FMT_CONSTEXPR20 buffer(T* p = nullptr, size_t sz = 0, size_t cap = 0) noexcept
+      : ptr_(p), size_(sz), capacity_(cap) {}
 
   FMT_CONSTEXPR20 ~buffer() = default;
   buffer(buffer&&) = default;
 
   /** Sets the buffer data and capacity. */
-  FMT_CONSTEXPR void set(T* buf_data, size_t buf_capacity) FMT_NOEXCEPT {
+  FMT_CONSTEXPR void set(T* buf_data, size_t buf_capacity) noexcept {
     ptr_ = buf_data;
     capacity_ = buf_capacity;
   }
@@ -810,23 +891,23 @@ template <typename T> class buffer {
   buffer(const buffer&) = delete;
   void operator=(const buffer&) = delete;
 
-  auto begin() FMT_NOEXCEPT -> T* { return ptr_; }
-  auto end() FMT_NOEXCEPT -> T* { return ptr_ + size_; }
+  FMT_INLINE auto begin() noexcept -> T* { return ptr_; }
+  FMT_INLINE auto end() noexcept -> T* { return ptr_ + size_; }
 
-  auto begin() const FMT_NOEXCEPT -> const T* { return ptr_; }
-  auto end() const FMT_NOEXCEPT -> const T* { return ptr_ + size_; }
+  FMT_INLINE auto begin() const noexcept -> const T* { return ptr_; }
+  FMT_INLINE auto end() const noexcept -> const T* { return ptr_ + size_; }
 
   /** Returns the size of this buffer. */
-  constexpr auto size() const FMT_NOEXCEPT -> size_t { return size_; }
+  constexpr auto size() const noexcept -> size_t { return size_; }
 
   /** Returns the capacity of this buffer. */
-  constexpr auto capacity() const FMT_NOEXCEPT -> size_t { return capacity_; }
+  constexpr auto capacity() const noexcept -> size_t { return capacity_; }
 
   /** Returns a pointer to the buffer data. */
-  FMT_CONSTEXPR auto data() FMT_NOEXCEPT -> T* { return ptr_; }
+  FMT_CONSTEXPR auto data() noexcept -> T* { return ptr_; }
 
   /** Returns a pointer to the buffer data. */
-  FMT_CONSTEXPR auto data() const FMT_NOEXCEPT -> const T* { return ptr_; }
+  FMT_CONSTEXPR auto data() const noexcept -> const T* { return ptr_; }
 
   /** Clears this buffer. */
   void clear() { size_ = 0; }
@@ -854,11 +935,11 @@ template <typename T> class buffer {
   /** Appends data to the end of the buffer. */
   template <typename U> void append(const U* begin, const U* end);
 
-  template <typename I> FMT_CONSTEXPR auto operator[](I index) -> T& {
+  template <typename Idx> FMT_CONSTEXPR auto operator[](Idx index) -> T& {
     return ptr_[index];
   }
-  template <typename I>
-  FMT_CONSTEXPR auto operator[](I index) const -> const T& {
+  template <typename Idx>
+  FMT_CONSTEXPR auto operator[](Idx index) const -> const T& {
     return ptr_[index];
   }
 };
@@ -993,6 +1074,7 @@ class iterator_buffer<std::back_insert_iterator<Container>,
       : buffer<typename Container::value_type>(c.size()), container_(c) {}
   explicit iterator_buffer(std::back_insert_iterator<Container> out, size_t = 0)
       : iterator_buffer(get_container(out)) {}
+
   auto out() -> std::back_insert_iterator<Container> {
     return std::back_inserter(container_);
   }
@@ -1027,25 +1109,21 @@ template <typename T, typename OutputIt>
 auto get_buffer(OutputIt out) -> iterator_buffer<OutputIt, T> {
   return iterator_buffer<OutputIt, T>(out);
 }
+template <typename T, typename Buf,
+          FMT_ENABLE_IF(std::is_base_of<buffer<char>, Buf>::value)>
+auto get_buffer(std::back_insert_iterator<Buf> out) -> buffer<char>& {
+  return get_container(out);
+}
 
-template <typename Buffer>
-auto get_iterator(Buffer& buf) -> decltype(buf.out()) {
+template <typename Buf, typename OutputIt>
+FMT_INLINE auto get_iterator(Buf& buf, OutputIt) -> decltype(buf.out()) {
   return buf.out();
 }
-template <typename T> auto get_iterator(buffer<T>& buf) -> buffer_appender<T> {
-  return buffer_appender<T>(buf);
+template <typename T, typename OutputIt>
+auto get_iterator(buffer<T>&, OutputIt out) -> OutputIt {
+  return out;
 }
 
-template <typename T, typename Char = char, typename Enable = void>
-struct fallback_formatter {
-  fallback_formatter() = delete;
-};
-
-// Specifies if T has an enabled fallback_formatter specialization.
-template <typename T, typename Char>
-using has_fallback_formatter =
-    std::is_constructible<fallback_formatter<T, Char>>;
-
 struct view {};
 
 template <typename Char, typename T> struct named_arg : view {
@@ -1128,64 +1206,8 @@ constexpr auto count_statically_named_args() -> size_t {
   return count<is_statically_named_arg<Args>::value...>();
 }
 
-enum class type {
-  none_type,
-  // Integer types should go first,
-  int_type,
-  uint_type,
-  long_long_type,
-  ulong_long_type,
-  int128_type,
-  uint128_type,
-  bool_type,
-  char_type,
-  last_integer_type = char_type,
-  // followed by floating-point types.
-  float_type,
-  double_type,
-  long_double_type,
-  last_numeric_type = long_double_type,
-  cstring_type,
-  string_type,
-  pointer_type,
-  custom_type
-};
-
-// Maps core type T to the corresponding type enum constant.
-template <typename T, typename Char>
-struct type_constant : std::integral_constant<type, type::custom_type> {};
-
-#define FMT_TYPE_CONSTANT(Type, constant) \
-  template <typename Char>                \
-  struct type_constant<Type, Char>        \
-      : std::integral_constant<type, type::constant> {}
-
-FMT_TYPE_CONSTANT(int, int_type);
-FMT_TYPE_CONSTANT(unsigned, uint_type);
-FMT_TYPE_CONSTANT(long long, long_long_type);
-FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
-FMT_TYPE_CONSTANT(int128_t, int128_type);
-FMT_TYPE_CONSTANT(uint128_t, uint128_type);
-FMT_TYPE_CONSTANT(bool, bool_type);
-FMT_TYPE_CONSTANT(Char, char_type);
-FMT_TYPE_CONSTANT(float, float_type);
-FMT_TYPE_CONSTANT(double, double_type);
-FMT_TYPE_CONSTANT(long double, long_double_type);
-FMT_TYPE_CONSTANT(const Char*, cstring_type);
-FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
-FMT_TYPE_CONSTANT(const void*, pointer_type);
-
-constexpr bool is_integral_type(type t) {
-  return t > type::none_type && t <= type::last_integer_type;
-}
-
-constexpr bool is_arithmetic_type(type t) {
-  return t > type::none_type && t <= type::last_numeric_type;
-}
-
 struct unformattable {};
 struct unformattable_char : unformattable {};
-struct unformattable_const : unformattable {};
 struct unformattable_pointer : unformattable {};
 
 template <typename Char> struct string_value {
@@ -1215,8 +1237,8 @@ template <typename Context> class value {
     unsigned uint_value;
     long long long_long_value;
     unsigned long long ulong_long_value;
-    int128_t int128_value;
-    uint128_t uint128_value;
+    int128_opt int128_value;
+    uint128_opt uint128_value;
     bool bool_value;
     char_type char_value;
     float float_value;
@@ -1233,8 +1255,8 @@ template <typename Context> class value {
   constexpr FMT_INLINE value(unsigned val) : uint_value(val) {}
   constexpr FMT_INLINE value(long long val) : long_long_value(val) {}
   constexpr FMT_INLINE value(unsigned long long val) : ulong_long_value(val) {}
-  FMT_INLINE value(int128_t val) : int128_value(val) {}
-  FMT_INLINE value(uint128_t val) : uint128_value(val) {}
+  FMT_INLINE value(int128_opt val) : int128_value(val) {}
+  FMT_INLINE value(uint128_opt val) : uint128_value(val) {}
   constexpr FMT_INLINE value(float val) : float_value(val) {}
   constexpr FMT_INLINE value(double val) : double_value(val) {}
   FMT_INLINE value(long double val) : long_double_value(val) {}
@@ -1259,14 +1281,10 @@ template <typename Context> class value {
     // have different extension points, e.g. `formatter<T>` for `format` and
     // `printf_formatter<T>` for `printf`.
     custom.format = format_custom_arg<
-        value_type,
-        conditional_t<has_formatter<value_type, Context>::value,
-                      typename Context::template formatter_type<value_type>,
-                      fallback_formatter<value_type, char_type>>>;
+        value_type, typename Context::template formatter_type<value_type>>;
   }
   value(unformattable);
   value(unformattable_char);
-  value(unformattable_const);
   value(unformattable_pointer);
 
  private:
@@ -1284,7 +1302,7 @@ template <typename Context> class value {
 };
 
 template <typename Context, typename T>
-FMT_CONSTEXPR auto make_arg(const T& value) -> basic_format_arg<Context>;
+FMT_CONSTEXPR auto make_arg(T&& value) -> basic_format_arg<Context>;
 
 // To minimize the number of types we need to deal with, long is translated
 // either to int or to long long depending on its size.
@@ -1292,6 +1310,20 @@ enum { long_short = sizeof(long) == sizeof(int) };
 using long_type = conditional_t<long_short, int, long long>;
 using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;
 
+template <typename T> struct format_as_result {
+  template <typename U,
+            FMT_ENABLE_IF(std::is_enum<U>::value || std::is_class<U>::value)>
+  static auto map(U*) -> decltype(format_as(std::declval<U>()));
+  static auto map(...) -> void;
+
+  using type = decltype(map(static_cast<T*>(nullptr)));
+};
+template <typename T> using format_as_t = typename format_as_result<T>::type;
+
+template <typename T>
+struct has_format_as
+    : bool_constant<!std::is_same<format_as_t<T>, void>::value> {};
+
 // Maps formatting arguments to core types.
 // arg_mapper reports errors by returning unformattable instead of using
 // static_assert because it's used in the is_formattable trait.
@@ -1317,8 +1349,12 @@ template <typename Context> struct arg_mapper {
       -> unsigned long long {
     return val;
   }
-  FMT_CONSTEXPR FMT_INLINE auto map(int128_t val) -> int128_t { return val; }
-  FMT_CONSTEXPR FMT_INLINE auto map(uint128_t val) -> uint128_t { return val; }
+  FMT_CONSTEXPR FMT_INLINE auto map(int128_opt val) -> int128_opt {
+    return val;
+  }
+  FMT_CONSTEXPR FMT_INLINE auto map(uint128_opt val) -> uint128_opt {
+    return val;
+  }
   FMT_CONSTEXPR FMT_INLINE auto map(bool val) -> bool { return val; }
 
   template <typename T, FMT_ENABLE_IF(std::is_same<T, char>::value ||
@@ -1363,46 +1399,6 @@ template <typename Context> struct arg_mapper {
   FMT_CONSTEXPR FMT_INLINE auto map(const T&) -> unformattable_char {
     return {};
   }
-  template <typename T,
-            FMT_ENABLE_IF(
-                std::is_constructible<basic_string_view<char_type>, T>::value &&
-                !is_string<T>::value && !has_formatter<T, Context>::value &&
-                !has_fallback_formatter<T, char_type>::value)>
-  FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
-      -> basic_string_view<char_type> {
-    return basic_string_view<char_type>(val);
-  }
-  template <
-      typename T,
-      FMT_ENABLE_IF(
-          std::is_constructible<std_string_view<char_type>, T>::value &&
-          !std::is_constructible<basic_string_view<char_type>, T>::value &&
-          !is_string<T>::value && !has_formatter<T, Context>::value &&
-          !has_fallback_formatter<T, char_type>::value)>
-  FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
-      -> basic_string_view<char_type> {
-    return std_string_view<char_type>(val);
-  }
-
-  using cstring_result = conditional_t<std::is_same<char_type, char>::value,
-                                       const char*, unformattable_pointer>;
-
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(const signed char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(const unsigned char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(signed char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
-  FMT_DEPRECATED FMT_CONSTEXPR FMT_INLINE auto map(unsigned char* val)
-      -> cstring_result {
-    return map(reinterpret_cast<const char*>(val));
-  }
 
   FMT_CONSTEXPR FMT_INLINE auto map(void* val) -> const void* { return val; }
   FMT_CONSTEXPR FMT_INLINE auto map(const void* val) -> const void* {
@@ -1412,15 +1408,16 @@ template <typename Context> struct arg_mapper {
     return val;
   }
 
-  // We use SFINAE instead of a const T* parameter to avoid conflicting with
-  // the C array overload.
+  // Use SFINAE instead of a const T* parameter to avoid a conflict with the
+  // array overload.
   template <
       typename T,
       FMT_ENABLE_IF(
-          std::is_member_pointer<T>::value ||
+          std::is_pointer<T>::value || std::is_member_pointer<T>::value ||
           std::is_function<typename std::remove_pointer<T>::type>::value ||
           (std::is_convertible<const T&, const void*>::value &&
-           !std::is_convertible<const T&, const char_type*>::value))>
+           !std::is_convertible<const T&, const char_type*>::value &&
+           !has_formatter<T, Context>::value))>
   FMT_CONSTEXPR auto map(const T&) -> unformattable_pointer {
     return {};
   }
@@ -1431,48 +1428,34 @@ template <typename Context> struct arg_mapper {
     return values;
   }
 
-  template <typename T,
-            FMT_ENABLE_IF(
-                std::is_enum<T>::value&& std::is_convertible<T, int>::value &&
-                !has_formatter<T, Context>::value &&
-                !has_fallback_formatter<T, char_type>::value)>
-  FMT_CONSTEXPR FMT_INLINE auto map(const T& val)
-      -> decltype(std::declval<arg_mapper>().map(
-          static_cast<typename std::underlying_type<T>::type>(val))) {
-    return map(static_cast<typename std::underlying_type<T>::type>(val));
-  }
-
-  FMT_CONSTEXPR FMT_INLINE auto map(detail::byte val) -> unsigned {
-    return map(static_cast<unsigned char>(val));
+  // Only map owning types because mapping views can be unsafe.
+  template <typename T, typename U = format_as_t<T>,
+            FMT_ENABLE_IF(std::is_arithmetic<U>::value)>
+  FMT_CONSTEXPR FMT_INLINE auto map(const T& val) -> decltype(this->map(U())) {
+    return map(format_as(val));
   }
 
   template <typename T, typename U = remove_cvref_t<T>>
   struct formattable
       : bool_constant<has_const_formatter<U, Context>() ||
-                      !std::is_const<remove_reference_t<T>>::value ||
-                      has_fallback_formatter<U, char_type>::value> {};
+                      (has_formatter<U, Context>::value &&
+                       !std::is_const<remove_reference_t<T>>::value)> {};
 
-#if FMT_MSC_VER != 0 && FMT_MSC_VER < 1910
-  // Workaround a bug in MSVC.
-  template <typename T> FMT_CONSTEXPR FMT_INLINE auto do_map(T&& val) -> T& {
-    return val;
-  }
-#else
   template <typename T, FMT_ENABLE_IF(formattable<T>::value)>
   FMT_CONSTEXPR FMT_INLINE auto do_map(T&& val) -> T& {
     return val;
   }
   template <typename T, FMT_ENABLE_IF(!formattable<T>::value)>
-  FMT_CONSTEXPR FMT_INLINE auto do_map(T&&) -> unformattable_const {
+  FMT_CONSTEXPR FMT_INLINE auto do_map(T&&) -> unformattable {
     return {};
   }
-#endif
 
   template <typename T, typename U = remove_cvref_t<T>,
-            FMT_ENABLE_IF(!is_string<U>::value && !is_char<U>::value &&
-                          !std::is_array<U>::value &&
-                          (has_formatter<U, Context>::value ||
-                           has_fallback_formatter<U, char_type>::value))>
+            FMT_ENABLE_IF((std::is_class<U>::value || std::is_enum<U>::value ||
+                           std::is_union<U>::value) &&
+                          !is_string<U>::value && !is_char<U>::value &&
+                          !is_named_arg<U>::value &&
+                          !std::is_arithmetic<format_as_t<U>>::value)>
   FMT_CONSTEXPR FMT_INLINE auto map(T&& val)
       -> decltype(this->do_map(std::forward<T>(val))) {
     return do_map(std::forward<T>(val));
@@ -1480,7 +1463,7 @@ template <typename Context> struct arg_mapper {
 
   template <typename T, FMT_ENABLE_IF(is_named_arg<T>::value)>
   FMT_CONSTEXPR FMT_INLINE auto map(const T& named_arg)
-      -> decltype(std::declval<arg_mapper>().map(named_arg.value)) {
+      -> decltype(this->map(named_arg.value)) {
     return map(named_arg.value);
   }
 
@@ -1498,27 +1481,20 @@ enum { packed_arg_bits = 4 };
 enum { max_packed_args = 62 / packed_arg_bits };
 enum : unsigned long long { is_unpacked_bit = 1ULL << 63 };
 enum : unsigned long long { has_named_args_bit = 1ULL << 62 };
-
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
 
 // An output iterator that appends to a buffer.
 // It is used to reduce symbol sizes for the common case.
 class appender : public std::back_insert_iterator<detail::buffer<char>> {
   using base = std::back_insert_iterator<detail::buffer<char>>;
 
-  template <typename T>
-  friend auto get_buffer(appender out) -> detail::buffer<char>& {
-    return detail::get_container(out);
-  }
-
  public:
   using std::back_insert_iterator<detail::buffer<char>>::back_insert_iterator;
-  appender(base it) FMT_NOEXCEPT : base(it) {}
-  using _Unchecked_type = appender;  // Mark iterator as checked.
+  appender(base it) noexcept : base(it) {}
+  FMT_UNCHECKED_ITERATOR(appender);
 
-  auto operator++() FMT_NOEXCEPT -> appender& { return *this; }
-
-  auto operator++(int) FMT_NOEXCEPT -> appender { return *this; }
+  auto operator++() noexcept -> appender& { return *this; }
+  auto operator++(int) noexcept -> appender { return *this; }
 };
 
 // A formatting argument. It is a trivially copyable/constructible type to
@@ -1529,7 +1505,7 @@ template <typename Context> class basic_format_arg {
   detail::type type_;
 
   template <typename ContextType, typename T>
-  friend FMT_CONSTEXPR auto detail::make_arg(const T& value)
+  friend FMT_CONSTEXPR auto detail::make_arg(T&& value)
       -> basic_format_arg<ContextType>;
 
   template <typename Visitor, typename Ctx>
@@ -1564,7 +1540,7 @@ template <typename Context> class basic_format_arg {
 
   constexpr basic_format_arg() : type_(detail::type::none_type) {}
 
-  constexpr explicit operator bool() const FMT_NOEXCEPT {
+  constexpr explicit operator bool() const noexcept {
     return type_ != detail::type::none_type;
   }
 
@@ -1583,6 +1559,7 @@ template <typename Context> class basic_format_arg {
   ``vis(value)`` will be called with the value of type ``double``.
   \endrst
  */
+FMT_MODULE_EXPORT
 template <typename Visitor, typename Context>
 FMT_CONSTEXPR FMT_INLINE auto visit_format_arg(
     Visitor&& vis, const basic_format_arg<Context>& arg) -> decltype(vis(0)) {
@@ -1624,7 +1601,7 @@ FMT_CONSTEXPR FMT_INLINE auto visit_format_arg(
   return vis(monostate());
 }
 
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
 
 template <typename Char, typename InputIt>
 auto copy_str(InputIt begin, InputIt end, appender out) -> appender {
@@ -1632,11 +1609,15 @@ auto copy_str(InputIt begin, InputIt end, appender out) -> appender {
   return out;
 }
 
+template <typename Char, typename R, typename OutputIt>
+FMT_CONSTEXPR auto copy_str(R&& rng, OutputIt out) -> OutputIt {
+  return detail::copy_str<Char>(rng.begin(), rng.end(), out);
+}
+
 #if FMT_GCC_VERSION && FMT_GCC_VERSION < 500
 // A workaround for gcc 4.8 to make void_t work in a SFINAE context.
-template <typename... Ts> struct void_t_impl { using type = void; };
-template <typename... Ts>
-using void_t = typename detail::void_t_impl<Ts...>::type;
+template <typename...> struct void_t_impl { using type = void; };
+template <typename... T> using void_t = typename void_t_impl<T...>::type;
 #else
 template <typename...> using void_t = void;
 #endif
@@ -1651,13 +1632,12 @@ struct is_output_iterator<
            decltype(*std::declval<It>() = std::declval<T>())>>
     : std::true_type {};
 
-template <typename OutputIt>
-struct is_back_insert_iterator : std::false_type {};
+template <typename It> struct is_back_insert_iterator : std::false_type {};
 template <typename Container>
 struct is_back_insert_iterator<std::back_insert_iterator<Container>>
     : std::true_type {};
 
-template <typename OutputIt>
+template <typename It>
 struct is_contiguous_back_insert_iterator : std::false_type {};
 template <typename Container>
 struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
@@ -1665,16 +1645,16 @@ struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
 template <>
 struct is_contiguous_back_insert_iterator<appender> : std::true_type {};
 
-// A type-erased reference to an std::locale to avoid heavy <locale> include.
+// A type-erased reference to an std::locale to avoid a heavy <locale> include.
 class locale_ref {
  private:
   const void* locale_;  // A type-erased pointer to std::locale.
 
  public:
-  constexpr locale_ref() : locale_(nullptr) {}
+  constexpr FMT_INLINE locale_ref() : locale_(nullptr) {}
   template <typename Locale> explicit locale_ref(const Locale& loc);
 
-  explicit operator bool() const FMT_NOEXCEPT { return locale_ != nullptr; }
+  explicit operator bool() const noexcept { return locale_ != nullptr; }
 
   template <typename Locale> auto get() const -> Locale;
 };
@@ -1690,40 +1670,23 @@ constexpr auto encode_types() -> unsigned long long {
 }
 
 template <typename Context, typename T>
-FMT_CONSTEXPR auto make_arg(const T& value) -> basic_format_arg<Context> {
-  basic_format_arg<Context> arg;
-  arg.type_ = mapped_type_constant<T, Context>::value;
-  arg.value_ = arg_mapper<Context>().map(value);
-  return arg;
-}
-
-// The type template parameter is there to avoid an ODR violation when using
-// a fallback formatter in one translation unit and an implicit conversion in
-// another (not recommended).
-template <bool IS_PACKED, typename Context, type, typename T,
-          FMT_ENABLE_IF(IS_PACKED)>
-FMT_CONSTEXPR FMT_INLINE auto make_arg(T&& val) -> value<Context> {
-  const auto& arg = arg_mapper<Context>().map(std::forward<T>(val));
+FMT_CONSTEXPR FMT_INLINE auto make_value(T&& val) -> value<Context> {
+  auto&& arg = arg_mapper<Context>().map(FMT_FORWARD(val));
+  using arg_type = remove_cvref_t<decltype(arg)>;
 
   constexpr bool formattable_char =
-      !std::is_same<decltype(arg), const unformattable_char&>::value;
+      !std::is_same<arg_type, unformattable_char>::value;
   static_assert(formattable_char, "Mixing character types is disallowed.");
 
-  constexpr bool formattable_const =
-      !std::is_same<decltype(arg), const unformattable_const&>::value;
-  static_assert(formattable_const, "Cannot format a const argument.");
-
-  // Formatting of arbitrary pointers is disallowed. If you want to output
-  // a pointer cast it to "void *" or "const void *". In particular, this
-  // forbids formatting of "[const] volatile char *" which is printed as bool
-  // by iostreams.
+  // Formatting of arbitrary pointers is disallowed. If you want to format a
+  // pointer cast it to `void*` or `const void*`. In particular, this forbids
+  // formatting of `[const] volatile char*` printed as bool by iostreams.
   constexpr bool formattable_pointer =
-      !std::is_same<decltype(arg), const unformattable_pointer&>::value;
+      !std::is_same<arg_type, unformattable_pointer>::value;
   static_assert(formattable_pointer,
                 "Formatting of non-void pointers is disallowed.");
 
-  constexpr bool formattable =
-      !std::is_same<decltype(arg), const unformattable&>::value;
+  constexpr bool formattable = !std::is_same<arg_type, unformattable>::value;
   static_assert(
       formattable,
       "Cannot format an argument. To make type T formattable provide a "
@@ -1731,19 +1694,33 @@ FMT_CONSTEXPR FMT_INLINE auto make_arg(T&& val) -> value<Context> {
   return {arg};
 }
 
+template <typename Context, typename T>
+FMT_CONSTEXPR auto make_arg(T&& value) -> basic_format_arg<Context> {
+  auto arg = basic_format_arg<Context>();
+  arg.type_ = mapped_type_constant<T, Context>::value;
+  arg.value_ = make_value<Context>(value);
+  return arg;
+}
+
+// The DEPRECATED type template parameter is there to avoid an ODR violation
+// when using a fallback formatter in one translation unit and an implicit
+// conversion in another (not recommended).
+template <bool IS_PACKED, typename Context, type, typename T,
+          FMT_ENABLE_IF(IS_PACKED)>
+FMT_CONSTEXPR FMT_INLINE auto make_arg(T&& val) -> value<Context> {
+  return make_value<Context>(val);
+}
+
 template <bool IS_PACKED, typename Context, type, typename T,
           FMT_ENABLE_IF(!IS_PACKED)>
-inline auto make_arg(const T& value) -> basic_format_arg<Context> {
+FMT_CONSTEXPR inline auto make_arg(T&& value) -> basic_format_arg<Context> {
   return make_arg<Context>(value);
 }
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
+FMT_BEGIN_EXPORT
 
 // Formatting context.
 template <typename OutputIt, typename Char> class basic_format_context {
- public:
-  /** The character type for the output. */
-  using char_type = Char;
-
  private:
   OutputIt out_;
   basic_format_args<basic_format_context> args_;
@@ -1752,31 +1729,32 @@ template <typename OutputIt, typename Char> class basic_format_context {
  public:
   using iterator = OutputIt;
   using format_arg = basic_format_arg<basic_format_context>;
+  using format_args = basic_format_args<basic_format_context>;
   using parse_context_type = basic_format_parse_context<Char>;
-  template <typename T> using formatter_type = formatter<T, char_type>;
+  template <typename T> using formatter_type = formatter<T, Char>;
+
+  /** The character type for the output. */
+  using char_type = Char;
 
   basic_format_context(basic_format_context&&) = default;
   basic_format_context(const basic_format_context&) = delete;
   void operator=(const basic_format_context&) = delete;
   /**
-   Constructs a ``basic_format_context`` object. References to the arguments are
-   stored in the object so make sure they have appropriate lifetimes.
+    Constructs a ``basic_format_context`` object. References to the arguments
+    are stored in the object so make sure they have appropriate lifetimes.
    */
-  constexpr basic_format_context(
-      OutputIt out, basic_format_args<basic_format_context> ctx_args,
-      detail::locale_ref loc = detail::locale_ref())
+  constexpr basic_format_context(OutputIt out, format_args ctx_args,
+                                 detail::locale_ref loc = {})
       : out_(out), args_(ctx_args), loc_(loc) {}
 
   constexpr auto arg(int id) const -> format_arg { return args_.get(id); }
-  FMT_CONSTEXPR auto arg(basic_string_view<char_type> name) -> format_arg {
+  FMT_CONSTEXPR auto arg(basic_string_view<Char> name) -> format_arg {
     return args_.get(name);
   }
-  FMT_CONSTEXPR auto arg_id(basic_string_view<char_type> name) -> int {
+  FMT_CONSTEXPR auto arg_id(basic_string_view<Char> name) -> int {
     return args_.get_id(name);
   }
-  auto args() const -> const basic_format_args<basic_format_context>& {
-    return args_;
-  }
+  auto args() const -> const format_args& { return args_; }
 
   FMT_CONSTEXPR auto error_handler() -> detail::error_handler { return {}; }
   void on_error(const char* message) { error_handler().on_error(message); }
@@ -1797,16 +1775,10 @@ using buffer_context =
     basic_format_context<detail::buffer_appender<Char>, Char>;
 using format_context = buffer_context<char>;
 
-// Workaround an alias issue: https://stackoverflow.com/q/62767544/471164.
-#define FMT_BUFFER_CONTEXT(Char) \
-  basic_format_context<detail::buffer_appender<Char>, Char>
-
 template <typename T, typename Char = char>
-using is_formattable = bool_constant<
-    !std::is_base_of<detail::unformattable,
-                     decltype(detail::arg_mapper<buffer_context<Char>>().map(
-                         std::declval<T>()))>::value &&
-    !detail::has_fallback_formatter<T, Char>::value>;
+using is_formattable = bool_constant<!std::is_base_of<
+    detail::unformattable, decltype(detail::arg_mapper<buffer_context<Char>>()
+                                        .map(std::declval<T>()))>::value>;
 
 /**
   \rst
@@ -1853,7 +1825,7 @@ class format_arg_store
         data_{detail::make_arg<
             is_packed, Context,
             detail::mapped_type_constant<remove_cvref_t<T>, Context>::value>(
-            std::forward<T>(args))...} {
+            FMT_FORWARD(args))...} {
     detail::init_named_args(data_.named_args(), 0, 0, args...);
   }
 };
@@ -1866,10 +1838,10 @@ class format_arg_store
   See `~fmt::arg` for lifetime considerations.
   \endrst
  */
-template <typename Context = format_context, typename... Args>
-constexpr auto make_format_args(Args&&... args)
-    -> format_arg_store<Context, remove_cvref_t<Args>...> {
-  return {std::forward<Args>(args)...};
+template <typename Context = format_context, typename... T>
+constexpr auto make_format_args(T&&... args)
+    -> format_arg_store<Context, remove_cvref_t<T>...> {
+  return {FMT_FORWARD(args)...};
 }
 
 /**
@@ -1888,6 +1860,7 @@ inline auto arg(const Char* name, const T& arg) -> detail::named_arg<Char, T> {
   static_assert(!detail::is_named_arg<T>(), "nested named arguments");
   return {name, arg};
 }
+FMT_END_EXPORT
 
 /**
   \rst
@@ -2013,20 +1986,28 @@ template <typename Context> class basic_format_args {
 /** An alias to ``basic_format_args<format_context>``. */
 // A separate type would result in shorter symbols but break ABI compatibility
 // between clang and gcc on ARM (#1919).
-using format_args = basic_format_args<format_context>;
-
-// We cannot use enum classes as bit fields because of a gcc bug
-// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414.
+FMT_MODULE_EXPORT using format_args = basic_format_args<format_context>;
+
+// We cannot use enum classes as bit fields because of a gcc bug, so we put them
+// in namespaces instead (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61414).
+// Additionally, if an underlying type is specified, older gcc incorrectly warns
+// that the type is too small. Both bugs are fixed in gcc 9.3.
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 903
+#  define FMT_ENUM_UNDERLYING_TYPE(type)
+#else
+#  define FMT_ENUM_UNDERLYING_TYPE(type) : type
+#endif
 namespace align {
-enum type { none, left, right, center, numeric };
+enum type FMT_ENUM_UNDERLYING_TYPE(unsigned char){none, left, right, center,
+                                                  numeric};
 }
 using align_t = align::type;
 namespace sign {
-enum type { none, minus, plus, space };
+enum type FMT_ENUM_UNDERLYING_TYPE(unsigned char){none, minus, plus, space};
 }
 using sign_t = sign::type;
 
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
 
 // Workaround an array initialization issue in gcc 4.8.
 template <typename Char> struct fill_t {
@@ -2038,7 +2019,7 @@ template <typename Char> struct fill_t {
  public:
   FMT_CONSTEXPR void operator=(basic_string_view<Char> s) {
     auto size = s.size();
-    if (size > max_size) return throw_format_error("invalid fill");
+    FMT_ASSERT(size <= max_size, "invalid fill");
     for (size_t i = 0; i < size; ++i) data_[i] = s[i];
     size_ = static_cast<unsigned char>(size);
   }
@@ -2051,11 +2032,10 @@ template <typename Char> struct fill_t {
     return data_[index];
   }
 };
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
 
 enum class presentation_type : unsigned char {
   none,
-  // Integer types should go first,
   dec,             // 'd'
   oct,             // 'o'
   hex_lower,       // 'x'
@@ -2072,11 +2052,12 @@ enum class presentation_type : unsigned char {
   general_upper,   // 'G'
   chr,             // 'c'
   string,          // 's'
-  pointer          // 'p'
+  pointer,         // 'p'
+  debug            // '?'
 };
 
 // Format specifiers for built-in and string types.
-template <typename Char> struct basic_format_specs {
+template <typename Char = char> struct format_specs {
   int width;
   int precision;
   presentation_type type;
@@ -2086,7 +2067,7 @@ template <typename Char> struct basic_format_specs {
   bool localized : 1;
   detail::fill_t<Char> fill;
 
-  constexpr basic_format_specs()
+  constexpr format_specs()
       : width(0),
         precision(-1),
         type(presentation_type::none),
@@ -2096,9 +2077,7 @@ template <typename Char> struct basic_format_specs {
         localized(false) {}
 };
 
-using format_specs = basic_format_specs<char>;
-
-FMT_BEGIN_DETAIL_NAMESPACE
+namespace detail {
 
 enum class arg_id_kind { none, index, name };
 
@@ -2119,7 +2098,7 @@ template <typename Char> struct arg_ref {
 
   arg_id_kind kind;
   union value {
-    FMT_CONSTEXPR value(int id = 0) : index{id} {}
+    FMT_CONSTEXPR value(int idx = 0) : index(idx) {}
     FMT_CONSTEXPR value(basic_string_view<Char> n) : name(n) {}
 
     int index;
@@ -2128,129 +2107,30 @@ template <typename Char> struct arg_ref {
 };
 
 // Format specifiers with width and precision resolved at formatting rather
-// than parsing time to allow re-using the same parsed specifiers with
+// than parsing time to allow reusing the same parsed specifiers with
 // different sets of arguments (precompilation of format strings).
-template <typename Char>
-struct dynamic_format_specs : basic_format_specs<Char> {
+template <typename Char = char>
+struct dynamic_format_specs : format_specs<Char> {
   arg_ref<Char> width_ref;
   arg_ref<Char> precision_ref;
 };
 
-struct auto_id {};
-
-// A format specifier handler that sets fields in basic_format_specs.
-template <typename Char> class specs_setter {
- protected:
-  basic_format_specs<Char>& specs_;
-
- public:
-  explicit FMT_CONSTEXPR specs_setter(basic_format_specs<Char>& specs)
-      : specs_(specs) {}
-
-  FMT_CONSTEXPR specs_setter(const specs_setter& other)
-      : specs_(other.specs_) {}
-
-  FMT_CONSTEXPR void on_align(align_t align) { specs_.align = align; }
-  FMT_CONSTEXPR void on_fill(basic_string_view<Char> fill) {
-    specs_.fill = fill;
-  }
-  FMT_CONSTEXPR void on_sign(sign_t s) { specs_.sign = s; }
-  FMT_CONSTEXPR void on_hash() { specs_.alt = true; }
-  FMT_CONSTEXPR void on_localized() { specs_.localized = true; }
-
-  FMT_CONSTEXPR void on_zero() {
-    if (specs_.align == align::none) specs_.align = align::numeric;
-    specs_.fill[0] = Char('0');
-  }
-
-  FMT_CONSTEXPR void on_width(int width) { specs_.width = width; }
-  FMT_CONSTEXPR void on_precision(int precision) {
-    specs_.precision = precision;
-  }
-  FMT_CONSTEXPR void end_precision() {}
-
-  FMT_CONSTEXPR void on_type(presentation_type type) { specs_.type = type; }
-};
-
-// Format spec handler that saves references to arguments representing dynamic
-// width and precision to be resolved at formatting time.
-template <typename ParseContext>
-class dynamic_specs_handler
-    : public specs_setter<typename ParseContext::char_type> {
- public:
-  using char_type = typename ParseContext::char_type;
-
-  FMT_CONSTEXPR dynamic_specs_handler(dynamic_format_specs<char_type>& specs,
-                                      ParseContext& ctx)
-      : specs_setter<char_type>(specs), specs_(specs), context_(ctx) {}
-
-  FMT_CONSTEXPR dynamic_specs_handler(const dynamic_specs_handler& other)
-      : specs_setter<char_type>(other),
-        specs_(other.specs_),
-        context_(other.context_) {}
-
-  template <typename Id> FMT_CONSTEXPR void on_dynamic_width(Id arg_id) {
-    specs_.width_ref = make_arg_ref(arg_id);
-  }
-
-  template <typename Id> FMT_CONSTEXPR void on_dynamic_precision(Id arg_id) {
-    specs_.precision_ref = make_arg_ref(arg_id);
-  }
-
-  FMT_CONSTEXPR void on_error(const char* message) {
-    context_.on_error(message);
-  }
-
- private:
-  dynamic_format_specs<char_type>& specs_;
-  ParseContext& context_;
-
-  using arg_ref_type = arg_ref<char_type>;
-
-  FMT_CONSTEXPR auto make_arg_ref(int arg_id) -> arg_ref_type {
-    context_.check_arg_id(arg_id);
-    return arg_ref_type(arg_id);
-  }
-
-  FMT_CONSTEXPR auto make_arg_ref(auto_id) -> arg_ref_type {
-    return arg_ref_type(context_.next_arg_id());
-  }
-
-  FMT_CONSTEXPR auto make_arg_ref(basic_string_view<char_type> arg_id)
-      -> arg_ref_type {
-    context_.check_arg_id(arg_id);
-    basic_string_view<char_type> format_str(
-        context_.begin(), to_unsigned(context_.end() - context_.begin()));
-    return arg_ref_type(arg_id);
-  }
-};
-
-template <typename Char> constexpr bool is_ascii_letter(Char c) {
-  return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
-}
-
-// Converts a character to ASCII. Returns a number > 127 on conversion failure.
+// Converts a character to ASCII. Returns '\0' on conversion failure.
 template <typename Char, FMT_ENABLE_IF(std::is_integral<Char>::value)>
-constexpr auto to_ascii(Char value) -> Char {
-  return value;
+constexpr auto to_ascii(Char c) -> char {
+  return c <= 0xff ? static_cast<char>(c) : '\0';
 }
 template <typename Char, FMT_ENABLE_IF(std::is_enum<Char>::value)>
-constexpr auto to_ascii(Char value) ->
-    typename std::underlying_type<Char>::type {
-  return value;
+constexpr auto to_ascii(Char c) -> char {
+  return c <= 0xff ? static_cast<char>(c) : '\0';
 }
 
+// Returns the number of code units in a code point or 1 on error.
 template <typename Char>
 FMT_CONSTEXPR auto code_point_length(const Char* begin) -> int {
   if (const_check(sizeof(Char) != 1)) return 1;
-  auto lengths =
-      "\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\0\0\0\0\0\0\0\0\2\2\2\2\3\3\4";
-  int len = lengths[static_cast<unsigned char>(*begin) >> 3];
-
-  // Compute the pointer to the next character early so that the next
-  // iteration can start working on the next character. Neither Clang
-  // nor GCC figure out this reordering on their own.
-  return len + !len;
+  auto c = static_cast<unsigned char>(*begin);
+  return static_cast<int>((0x3a55000000000000ull >> (2 * (c >> 3))) & 0x3) + 1;
 }
 
 // Return the result via the out param to workaround gcc bug 77539.
@@ -2295,277 +2175,284 @@ FMT_CONSTEXPR auto parse_nonnegative_int(const Char*& begin, const Char* end,
              : error_value;
 }
 
-// Parses fill and alignment.
-template <typename Char, typename Handler>
-FMT_CONSTEXPR auto parse_align(const Char* begin, const Char* end,
-                               Handler&& handler) -> const Char* {
-  FMT_ASSERT(begin != end, "");
-  auto align = align::none;
-  auto p = begin + code_point_length(begin);
-  if (p >= end) p = begin;
-  for (;;) {
-    switch (to_ascii(*p)) {
-    case '<':
-      align = align::left;
-      break;
-    case '>':
-      align = align::right;
-      break;
-    case '^':
-      align = align::center;
-      break;
-    default:
-      break;
-    }
-    if (align != align::none) {
-      if (p != begin) {
-        auto c = *begin;
-        if (c == '{')
-          return handler.on_error("invalid fill character '{'"), begin;
-        handler.on_fill(basic_string_view<Char>(begin, to_unsigned(p - begin)));
-        begin = p + 1;
-      } else
-        ++begin;
-      handler.on_align(align);
-      break;
-    } else if (p == begin) {
-      break;
-    }
-    p = begin;
+FMT_CONSTEXPR inline auto parse_align(char c) -> align_t {
+  switch (c) {
+  case '<':
+    return align::left;
+  case '>':
+    return align::right;
+  case '^':
+    return align::center;
   }
-  return begin;
+  return align::none;
 }
 
-template <typename Char> FMT_CONSTEXPR bool is_name_start(Char c) {
-  return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || '_' == c;
+template <typename Char> constexpr auto is_name_start(Char c) -> bool {
+  return ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || c == '_';
 }
 
-template <typename Char, typename IDHandler>
+template <typename Char, typename Handler>
 FMT_CONSTEXPR auto do_parse_arg_id(const Char* begin, const Char* end,
-                                   IDHandler&& handler) -> const Char* {
-  FMT_ASSERT(begin != end, "");
+                                   Handler&& handler) -> const Char* {
   Char c = *begin;
   if (c >= '0' && c <= '9') {
     int index = 0;
+    constexpr int max = (std::numeric_limits<int>::max)();
     if (c != '0')
-      index =
-          parse_nonnegative_int(begin, end, (std::numeric_limits<int>::max)());
+      index = parse_nonnegative_int(begin, end, max);
     else
       ++begin;
     if (begin == end || (*begin != '}' && *begin != ':'))
-      handler.on_error("invalid format string");
+      throw_format_error("invalid format string");
     else
-      handler(index);
+      handler.on_index(index);
     return begin;
   }
   if (!is_name_start(c)) {
-    handler.on_error("invalid format string");
+    throw_format_error("invalid format string");
     return begin;
   }
   auto it = begin;
   do {
     ++it;
-  } while (it != end && (is_name_start(c = *it) || ('0' <= c && c <= '9')));
-  handler(basic_string_view<Char>(begin, to_unsigned(it - begin)));
+  } while (it != end && (is_name_start(*it) || ('0' <= *it && *it <= '9')));
+  handler.on_name({begin, to_unsigned(it - begin)});
   return it;
 }
 
-template <typename Char, typename IDHandler>
+template <typename Char, typename Handler>
 FMT_CONSTEXPR FMT_INLINE auto parse_arg_id(const Char* begin, const Char* end,
-                                           IDHandler&& handler) -> const Char* {
+                                           Handler&& handler) -> const Char* {
+  FMT_ASSERT(begin != end, "");
   Char c = *begin;
   if (c != '}' && c != ':') return do_parse_arg_id(begin, end, handler);
-  handler();
+  handler.on_auto();
   return begin;
 }
 
-template <typename Char, typename Handler>
-FMT_CONSTEXPR auto parse_width(const Char* begin, const Char* end,
-                               Handler&& handler) -> const Char* {
-  using detail::auto_id;
-  struct width_adapter {
-    Handler& handler;
+template <typename Char> struct dynamic_spec_id_handler {
+  basic_format_parse_context<Char>& ctx;
+  arg_ref<Char>& ref;
 
-    FMT_CONSTEXPR void operator()() { handler.on_dynamic_width(auto_id()); }
-    FMT_CONSTEXPR void operator()(int id) { handler.on_dynamic_width(id); }
-    FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
-      handler.on_dynamic_width(id);
-    }
-    FMT_CONSTEXPR void on_error(const char* message) {
-      if (message) handler.on_error(message);
-    }
-  };
+  FMT_CONSTEXPR void on_auto() {
+    int id = ctx.next_arg_id();
+    ref = arg_ref<Char>(id);
+    ctx.check_dynamic_spec(id);
+  }
+  FMT_CONSTEXPR void on_index(int id) {
+    ref = arg_ref<Char>(id);
+    ctx.check_arg_id(id);
+    ctx.check_dynamic_spec(id);
+  }
+  FMT_CONSTEXPR void on_name(basic_string_view<Char> id) {
+    ref = arg_ref<Char>(id);
+    ctx.check_arg_id(id);
+  }
+};
 
+// Parses [integer | "{" [arg_id] "}"].
+template <typename Char>
+FMT_CONSTEXPR auto parse_dynamic_spec(const Char* begin, const Char* end,
+                                      int& value, arg_ref<Char>& ref,
+                                      basic_format_parse_context<Char>& ctx)
+    -> const Char* {
   FMT_ASSERT(begin != end, "");
   if ('0' <= *begin && *begin <= '9') {
-    int width = parse_nonnegative_int(begin, end, -1);
-    if (width != -1)
-      handler.on_width(width);
+    int val = parse_nonnegative_int(begin, end, -1);
+    if (val != -1)
+      value = val;
     else
-      handler.on_error("number is too big");
+      throw_format_error("number is too big");
   } else if (*begin == '{') {
     ++begin;
-    if (begin != end) begin = parse_arg_id(begin, end, width_adapter{handler});
-    if (begin == end || *begin != '}')
-      return handler.on_error("invalid format string"), begin;
-    ++begin;
+    auto handler = dynamic_spec_id_handler<Char>{ctx, ref};
+    if (begin != end) begin = parse_arg_id(begin, end, handler);
+    if (begin != end && *begin == '}') return ++begin;
+    throw_format_error("invalid format string");
   }
   return begin;
 }
 
-template <typename Char, typename Handler>
-FMT_CONSTEXPR auto parse_precision(const Char* begin, const Char* end,
-                                   Handler&& handler) -> const Char* {
-  using detail::auto_id;
-  struct precision_adapter {
-    Handler& handler;
-
-    FMT_CONSTEXPR void operator()() { handler.on_dynamic_precision(auto_id()); }
-    FMT_CONSTEXPR void operator()(int id) { handler.on_dynamic_precision(id); }
-    FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
-      handler.on_dynamic_precision(id);
-    }
-    FMT_CONSTEXPR void on_error(const char* message) {
-      if (message) handler.on_error(message);
-    }
-  };
-
-  ++begin;
-  auto c = begin != end ? *begin : Char();
-  if ('0' <= c && c <= '9') {
-    auto precision = parse_nonnegative_int(begin, end, -1);
-    if (precision != -1)
-      handler.on_precision(precision);
-    else
-      handler.on_error("number is too big");
-  } else if (c == '{') {
-    ++begin;
-    if (begin != end)
-      begin = parse_arg_id(begin, end, precision_adapter{handler});
-    if (begin == end || *begin++ != '}')
-      return handler.on_error("invalid format string"), begin;
-  } else {
-    return handler.on_error("missing precision specifier"), begin;
-  }
-  handler.end_precision();
-  return begin;
-}
-
 template <typename Char>
-FMT_CONSTEXPR auto parse_presentation_type(Char type) -> presentation_type {
-  switch (to_ascii(type)) {
-  case 'd':
-    return presentation_type::dec;
-  case 'o':
-    return presentation_type::oct;
-  case 'x':
-    return presentation_type::hex_lower;
-  case 'X':
-    return presentation_type::hex_upper;
-  case 'b':
-    return presentation_type::bin_lower;
-  case 'B':
-    return presentation_type::bin_upper;
-  case 'a':
-    return presentation_type::hexfloat_lower;
-  case 'A':
-    return presentation_type::hexfloat_upper;
-  case 'e':
-    return presentation_type::exp_lower;
-  case 'E':
-    return presentation_type::exp_upper;
-  case 'f':
-    return presentation_type::fixed_lower;
-  case 'F':
-    return presentation_type::fixed_upper;
-  case 'g':
-    return presentation_type::general_lower;
-  case 'G':
-    return presentation_type::general_upper;
-  case 'c':
-    return presentation_type::chr;
-  case 's':
-    return presentation_type::string;
-  case 'p':
-    return presentation_type::pointer;
-  default:
-    return presentation_type::none;
-  }
-}
-
-// Parses standard format specifiers and sends notifications about parsed
-// components to handler.
-template <typename Char, typename SpecHandler>
-FMT_CONSTEXPR FMT_INLINE auto parse_format_specs(const Char* begin,
-                                                 const Char* end,
-                                                 SpecHandler&& handler)
+FMT_CONSTEXPR auto parse_precision(const Char* begin, const Char* end,
+                                   int& value, arg_ref<Char>& ref,
+                                   basic_format_parse_context<Char>& ctx)
     -> const Char* {
-  if (1 < end - begin && begin[1] == '}' && is_ascii_letter(*begin) &&
-      *begin != 'L') {
-    presentation_type type = parse_presentation_type(*begin++);
-    if (type == presentation_type::none)
-      handler.on_error("invalid type specifier");
-    handler.on_type(type);
+  ++begin;
+  if (begin == end || *begin == '}') {
+    throw_format_error("invalid precision");
     return begin;
   }
+  return parse_dynamic_spec(begin, end, value, ref, ctx);
+}
 
-  if (begin == end) return begin;
-
-  begin = parse_align(begin, end, handler);
-  if (begin == end) return begin;
-
-  // Parse sign.
-  switch (to_ascii(*begin)) {
-  case '+':
-    handler.on_sign(sign::plus);
-    ++begin;
-    break;
-  case '-':
-    handler.on_sign(sign::minus);
-    ++begin;
-    break;
-  case ' ':
-    handler.on_sign(sign::space);
-    ++begin;
-    break;
-  default:
-    break;
-  }
-  if (begin == end) return begin;
-
-  if (*begin == '#') {
-    handler.on_hash();
-    if (++begin == end) return begin;
-  }
-
-  // Parse zero flag.
-  if (*begin == '0') {
-    handler.on_zero();
-    if (++begin == end) return begin;
-  }
-
-  begin = parse_width(begin, end, handler);
-  if (begin == end) return begin;
+enum class state { start, align, sign, hash, zero, width, precision, locale };
 
-  // Parse precision.
-  if (*begin == '.') {
-    begin = parse_precision(begin, end, handler);
+// Parses standard format specifiers.
+template <typename Char>
+FMT_CONSTEXPR FMT_INLINE auto parse_format_specs(
+    const Char* begin, const Char* end, dynamic_format_specs<Char>& specs,
+    basic_format_parse_context<Char>& ctx, type arg_type) -> const Char* {
+  auto c = '\0';
+  if (end - begin > 1) {
+    auto next = to_ascii(begin[1]);
+    c = parse_align(next) == align::none ? to_ascii(*begin) : '\0';
+  } else {
     if (begin == end) return begin;
+    c = to_ascii(*begin);
   }
 
-  if (*begin == 'L') {
-    handler.on_localized();
-    ++begin;
-  }
+  struct {
+    state current_state = state::start;
+    FMT_CONSTEXPR void operator()(state s, bool valid = true) {
+      if (current_state >= s || !valid)
+        throw_format_error("invalid format specifier");
+      current_state = s;
+    }
+  } enter_state;
+
+  using pres = presentation_type;
+  constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
+  struct {
+    const Char*& begin;
+    dynamic_format_specs<Char>& specs;
+    type arg_type;
+
+    FMT_CONSTEXPR auto operator()(pres type, int set) -> const Char* {
+      if (!in(arg_type, set)) throw_format_error("invalid format specifier");
+      specs.type = type;
+      return begin + 1;
+    }
+  } parse_presentation_type{begin, specs, arg_type};
 
-  // Parse type.
-  if (begin != end && *begin != '}') {
-    presentation_type type = parse_presentation_type(*begin++);
-    if (type == presentation_type::none)
-      handler.on_error("invalid type specifier");
-    handler.on_type(type);
+  for (;;) {
+    switch (c) {
+    case '<':
+    case '>':
+    case '^':
+      enter_state(state::align);
+      specs.align = parse_align(c);
+      ++begin;
+      break;
+    case '+':
+    case '-':
+    case ' ':
+      enter_state(state::sign, in(arg_type, sint_set | float_set));
+      switch (c) {
+      case '+':
+        specs.sign = sign::plus;
+        break;
+      case '-':
+        specs.sign = sign::minus;
+        break;
+      case ' ':
+        specs.sign = sign::space;
+        break;
+      }
+      ++begin;
+      break;
+    case '#':
+      enter_state(state::hash, is_arithmetic_type(arg_type));
+      specs.alt = true;
+      ++begin;
+      break;
+    case '0':
+      enter_state(state::zero);
+      if (!is_arithmetic_type(arg_type))
+        throw_format_error("format specifier requires numeric argument");
+      if (specs.align == align::none) {
+        // Ignore 0 if align is specified for compatibility with std::format.
+        specs.align = align::numeric;
+        specs.fill[0] = Char('0');
+      }
+      ++begin;
+      break;
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9':
+    case '{':
+      enter_state(state::width);
+      begin = parse_dynamic_spec(begin, end, specs.width, specs.width_ref, ctx);
+      break;
+    case '.':
+      enter_state(state::precision,
+                  in(arg_type, float_set | string_set | cstring_set));
+      begin = parse_precision(begin, end, specs.precision, specs.precision_ref,
+                              ctx);
+      break;
+    case 'L':
+      enter_state(state::locale, is_arithmetic_type(arg_type));
+      specs.localized = true;
+      ++begin;
+      break;
+    case 'd':
+      return parse_presentation_type(pres::dec, integral_set);
+    case 'o':
+      return parse_presentation_type(pres::oct, integral_set);
+    case 'x':
+      return parse_presentation_type(pres::hex_lower, integral_set);
+    case 'X':
+      return parse_presentation_type(pres::hex_upper, integral_set);
+    case 'b':
+      return parse_presentation_type(pres::bin_lower, integral_set);
+    case 'B':
+      return parse_presentation_type(pres::bin_upper, integral_set);
+    case 'a':
+      return parse_presentation_type(pres::hexfloat_lower, float_set);
+    case 'A':
+      return parse_presentation_type(pres::hexfloat_upper, float_set);
+    case 'e':
+      return parse_presentation_type(pres::exp_lower, float_set);
+    case 'E':
+      return parse_presentation_type(pres::exp_upper, float_set);
+    case 'f':
+      return parse_presentation_type(pres::fixed_lower, float_set);
+    case 'F':
+      return parse_presentation_type(pres::fixed_upper, float_set);
+    case 'g':
+      return parse_presentation_type(pres::general_lower, float_set);
+    case 'G':
+      return parse_presentation_type(pres::general_upper, float_set);
+    case 'c':
+      return parse_presentation_type(pres::chr, integral_set);
+    case 's':
+      return parse_presentation_type(pres::string,
+                                     bool_set | string_set | cstring_set);
+    case 'p':
+      return parse_presentation_type(pres::pointer, pointer_set | cstring_set);
+    case '?':
+      return parse_presentation_type(pres::debug,
+                                     char_set | string_set | cstring_set);
+    case '}':
+      return begin;
+    default: {
+      if (*begin == '}') return begin;
+      // Parse fill and alignment.
+      auto fill_end = begin + code_point_length(begin);
+      if (end - fill_end <= 0) {
+        throw_format_error("invalid format specifier");
+        return begin;
+      }
+      if (*begin == '{') {
+        throw_format_error("invalid fill character '{'");
+        return begin;
+      }
+      auto align = parse_align(to_ascii(*fill_end));
+      enter_state(state::align, align != align::none);
+      specs.fill = {begin, to_unsigned(fill_end - begin)};
+      specs.align = align;
+      begin = fill_end + 1;
+    }
+    }
+    if (begin == end) return begin;
+    c = to_ascii(*begin);
   }
-  return begin;
 }
 
 template <typename Char, typename Handler>
@@ -2575,14 +2462,11 @@ FMT_CONSTEXPR auto parse_replacement_field(const Char* begin, const Char* end,
     Handler& handler;
     int arg_id;
 
-    FMT_CONSTEXPR void operator()() { arg_id = handler.on_arg_id(); }
-    FMT_CONSTEXPR void operator()(int id) { arg_id = handler.on_arg_id(id); }
-    FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
+    FMT_CONSTEXPR void on_auto() { arg_id = handler.on_arg_id(); }
+    FMT_CONSTEXPR void on_index(int id) { arg_id = handler.on_arg_id(id); }
+    FMT_CONSTEXPR void on_name(basic_string_view<Char> id) {
       arg_id = handler.on_arg_id(id);
     }
-    FMT_CONSTEXPR void on_error(const char* message) {
-      if (message) handler.on_error(message);
-    }
   };
 
   ++begin;
@@ -2611,9 +2495,6 @@ FMT_CONSTEXPR auto parse_replacement_field(const Char* begin, const Char* end,
 template <bool IS_CONSTEXPR, typename Char, typename Handler>
 FMT_CONSTEXPR FMT_INLINE void parse_format_string(
     basic_string_view<Char> format_str, Handler&& handler) {
-  // Workaround a name-lookup bug in MSVC's modules implementation.
-  using detail::find;
-
   auto begin = format_str.data();
   auto end = begin + format_str.size();
   if (end - begin < 32) {
@@ -2635,21 +2516,21 @@ FMT_CONSTEXPR FMT_INLINE void parse_format_string(
     return;
   }
   struct writer {
-    FMT_CONSTEXPR void operator()(const Char* pbegin, const Char* pend) {
-      if (pbegin == pend) return;
+    FMT_CONSTEXPR void operator()(const Char* from, const Char* to) {
+      if (from == to) return;
       for (;;) {
         const Char* p = nullptr;
-        if (!find<IS_CONSTEXPR>(pbegin, pend, Char('}'), p))
-          return handler_.on_text(pbegin, pend);
+        if (!find<IS_CONSTEXPR>(from, to, Char('}'), p))
+          return handler_.on_text(from, to);
         ++p;
-        if (p == pend || *p != '}')
+        if (p == to || *p != '}')
           return handler_.on_error("unmatched '}' in format string");
-        handler_.on_text(pbegin, p);
-        pbegin = p + 1;
+        handler_.on_text(from, p);
+        from = p + 1;
       }
     }
     Handler& handler_;
-  } write{handler};
+  } write = {handler};
   while (begin != end) {
     // Doing two passes with memchr (one for '{' and another for '}') is up to
     // 2.5x faster than the naive one-pass implementation on big format strings.
@@ -2661,6 +2542,13 @@ FMT_CONSTEXPR FMT_INLINE void parse_format_string(
   }
 }
 
+template <typename T, bool = is_named_arg<T>::value> struct strip_named_arg {
+  using type = T;
+};
+template <typename T> struct strip_named_arg<T, true> {
+  using type = remove_cvref_t<decltype(T::value)>;
+};
+
 template <typename T, typename ParseContext>
 FMT_CONSTEXPR auto parse_format_specs(ParseContext& ctx)
     -> decltype(ctx.begin()) {
@@ -2668,206 +2556,30 @@ FMT_CONSTEXPR auto parse_format_specs(ParseContext& ctx)
   using context = buffer_context<char_type>;
   using mapped_type = conditional_t<
       mapped_type_constant<T, context>::value != type::custom_type,
-      decltype(arg_mapper<context>().map(std::declval<const T&>())), T>;
-  auto f = conditional_t<has_formatter<mapped_type, context>::value,
-                         formatter<mapped_type, char_type>,
-                         fallback_formatter<T, char_type>>();
-  return f.parse(ctx);
-}
-
-// A parse context with extra argument id checks. It is only used at compile
-// time because adding checks at runtime would introduce substantial overhead
-// and would be redundant since argument ids are checked when arguments are
-// retrieved anyway.
-template <typename Char, typename ErrorHandler = error_handler>
-class compile_parse_context
-    : public basic_format_parse_context<Char, ErrorHandler> {
- private:
-  int num_args_;
-  using base = basic_format_parse_context<Char, ErrorHandler>;
-
- public:
-  explicit FMT_CONSTEXPR compile_parse_context(
-      basic_string_view<Char> format_str,
-      int num_args = (std::numeric_limits<int>::max)(), ErrorHandler eh = {})
-      : base(format_str, eh), num_args_(num_args) {}
-
-  FMT_CONSTEXPR auto next_arg_id() -> int {
-    int id = base::next_arg_id();
-    if (id >= num_args_) this->on_error("argument not found");
-    return id;
-  }
-
-  FMT_CONSTEXPR void check_arg_id(int id) {
-    base::check_arg_id(id);
-    if (id >= num_args_) this->on_error("argument not found");
-  }
-  using base::check_arg_id;
-};
-
-template <typename ErrorHandler>
-FMT_CONSTEXPR void check_int_type_spec(presentation_type type,
-                                       ErrorHandler&& eh) {
-  if (type > presentation_type::bin_upper && type != presentation_type::chr)
-    eh.on_error("invalid type specifier");
+      decltype(arg_mapper<context>().map(std::declval<const T&>())),
+      typename strip_named_arg<T>::type>;
+  return formatter<mapped_type, char_type>().parse(ctx);
 }
 
-// Checks char specs and returns true if the type spec is char (and not int).
-template <typename Char, typename ErrorHandler = error_handler>
-FMT_CONSTEXPR auto check_char_specs(const basic_format_specs<Char>& specs,
-                                    ErrorHandler&& eh = {}) -> bool {
+// Checks char specs and returns true iff the presentation type is char-like.
+template <typename Char>
+FMT_CONSTEXPR auto check_char_specs(const format_specs<Char>& specs) -> bool {
   if (specs.type != presentation_type::none &&
-      specs.type != presentation_type::chr) {
-    check_int_type_spec(specs.type, eh);
+      specs.type != presentation_type::chr &&
+      specs.type != presentation_type::debug) {
     return false;
   }
   if (specs.align == align::numeric || specs.sign != sign::none || specs.alt)
-    eh.on_error("invalid format specifier for char");
+    throw_format_error("invalid format specifier for char");
   return true;
 }
 
-// A floating-point presentation format.
-enum class float_format : unsigned char {
-  general,  // General: exponent notation or fixed point based on magnitude.
-  exp,      // Exponent notation with the default precision of 6, e.g. 1.2e-3.
-  fixed,    // Fixed point with the default precision of 6, e.g. 0.0012.
-  hex
-};
+constexpr FMT_INLINE_VARIABLE int invalid_arg_index = -1;
 
-struct float_specs {
-  int precision;
-  float_format format : 8;
-  sign_t sign : 8;
-  bool upper : 1;
-  bool locale : 1;
-  bool binary32 : 1;
-  bool fallback : 1;
-  bool showpoint : 1;
-};
-
-template <typename ErrorHandler = error_handler, typename Char>
-FMT_CONSTEXPR auto parse_float_type_spec(const basic_format_specs<Char>& specs,
-                                         ErrorHandler&& eh = {})
-    -> float_specs {
-  auto result = float_specs();
-  result.showpoint = specs.alt;
-  result.locale = specs.localized;
-  switch (specs.type) {
-  case presentation_type::none:
-    result.format = float_format::general;
-    break;
-  case presentation_type::general_upper:
-    result.upper = true;
-    FMT_FALLTHROUGH;
-  case presentation_type::general_lower:
-    result.format = float_format::general;
-    break;
-  case presentation_type::exp_upper:
-    result.upper = true;
-    FMT_FALLTHROUGH;
-  case presentation_type::exp_lower:
-    result.format = float_format::exp;
-    result.showpoint |= specs.precision != 0;
-    break;
-  case presentation_type::fixed_upper:
-    result.upper = true;
-    FMT_FALLTHROUGH;
-  case presentation_type::fixed_lower:
-    result.format = float_format::fixed;
-    result.showpoint |= specs.precision != 0;
-    break;
-  case presentation_type::hexfloat_upper:
-    result.upper = true;
-    FMT_FALLTHROUGH;
-  case presentation_type::hexfloat_lower:
-    result.format = float_format::hex;
-    break;
-  default:
-    eh.on_error("invalid type specifier");
-    break;
-  }
-  return result;
-}
-
-template <typename ErrorHandler = error_handler>
-FMT_CONSTEXPR auto check_cstring_type_spec(presentation_type type,
-                                           ErrorHandler&& eh = {}) -> bool {
-  if (type == presentation_type::none || type == presentation_type::string)
-    return true;
-  if (type != presentation_type::pointer) eh.on_error("invalid type specifier");
-  return false;
-}
-
-template <typename ErrorHandler = error_handler>
-FMT_CONSTEXPR void check_string_type_spec(presentation_type type,
-                                          ErrorHandler&& eh = {}) {
-  if (type != presentation_type::none && type != presentation_type::string)
-    eh.on_error("invalid type specifier");
-}
-
-template <typename ErrorHandler>
-FMT_CONSTEXPR void check_pointer_type_spec(presentation_type type,
-                                           ErrorHandler&& eh) {
-  if (type != presentation_type::none && type != presentation_type::pointer)
-    eh.on_error("invalid type specifier");
-}
-
-// A parse_format_specs handler that checks if specifiers are consistent with
-// the argument type.
-template <typename Handler> class specs_checker : public Handler {
- private:
-  detail::type arg_type_;
-
-  FMT_CONSTEXPR void require_numeric_argument() {
-    if (!is_arithmetic_type(arg_type_))
-      this->on_error("format specifier requires numeric argument");
-  }
-
- public:
-  FMT_CONSTEXPR specs_checker(const Handler& handler, detail::type arg_type)
-      : Handler(handler), arg_type_(arg_type) {}
-
-  FMT_CONSTEXPR void on_align(align_t align) {
-    if (align == align::numeric) require_numeric_argument();
-    Handler::on_align(align);
-  }
-
-  FMT_CONSTEXPR void on_sign(sign_t s) {
-    require_numeric_argument();
-    if (is_integral_type(arg_type_) && arg_type_ != type::int_type &&
-        arg_type_ != type::long_long_type && arg_type_ != type::char_type) {
-      this->on_error("format specifier requires signed argument");
-    }
-    Handler::on_sign(s);
-  }
-
-  FMT_CONSTEXPR void on_hash() {
-    require_numeric_argument();
-    Handler::on_hash();
-  }
-
-  FMT_CONSTEXPR void on_localized() {
-    require_numeric_argument();
-    Handler::on_localized();
-  }
-
-  FMT_CONSTEXPR void on_zero() {
-    require_numeric_argument();
-    Handler::on_zero();
-  }
-
-  FMT_CONSTEXPR void end_precision() {
-    if (is_integral_type(arg_type_) || arg_type_ == type::pointer_type)
-      this->on_error("precision not allowed for this argument type");
-  }
-};
-
-constexpr int invalid_arg_index = -1;
-
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
 template <int N, typename T, typename... Args, typename Char>
 constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
-  if constexpr (detail::is_statically_named_arg<T>()) {
+  if constexpr (is_statically_named_arg<T>()) {
     if (name == T::name) return N;
   }
   if constexpr (sizeof...(Args) > 0)
@@ -2879,7 +2591,7 @@ constexpr auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
 
 template <typename... Args, typename Char>
 FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
   if constexpr (sizeof...(Args) > 0)
     return get_arg_index_by_name<0, Args...>(name);
 #endif
@@ -2887,23 +2599,26 @@ FMT_CONSTEXPR auto get_arg_index_by_name(basic_string_view<Char> name) -> int {
   return invalid_arg_index;
 }
 
-template <typename Char, typename ErrorHandler, typename... Args>
-class format_string_checker {
+template <typename Char, typename... Args> class format_string_checker {
  private:
-  using parse_context_type = compile_parse_context<Char, ErrorHandler>;
-  enum { num_args = sizeof...(Args) };
+  using parse_context_type = compile_parse_context<Char>;
+  static constexpr int num_args = sizeof...(Args);
 
   // Format specifier parsing function.
+  // In the future basic_format_parse_context will replace compile_parse_context
+  // here and will use is_constant_evaluated and downcasting to access the data
+  // needed for compile-time checks: https://godbolt.org/z/GvWzcTjh1.
   using parse_func = const Char* (*)(parse_context_type&);
 
   parse_context_type context_;
-  parse_func parse_funcs_[num_args > 0 ? num_args : 1];
+  parse_func parse_funcs_[num_args > 0 ? static_cast<size_t>(num_args) : 1];
+  type types_[num_args > 0 ? static_cast<size_t>(num_args) : 1];
 
  public:
-  explicit FMT_CONSTEXPR format_string_checker(
-      basic_string_view<Char> format_str, ErrorHandler eh)
-      : context_(format_str, num_args, eh),
-        parse_funcs_{&parse_format_specs<Args, parse_context_type>...} {}
+  explicit FMT_CONSTEXPR format_string_checker(basic_string_view<Char> fmt)
+      : context_(fmt, num_args, types_),
+        parse_funcs_{&parse_format_specs<Args, parse_context_type>...},
+        types_{mapped_type_constant<Args, buffer_context<Char>>::value...} {}
 
   FMT_CONSTEXPR void on_text(const Char*, const Char*) {}
 
@@ -2912,10 +2627,10 @@ class format_string_checker {
     return context_.check_arg_id(id), id;
   }
   FMT_CONSTEXPR auto on_arg_id(basic_string_view<Char> id) -> int {
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
     auto index = get_arg_index_by_name<Args...>(id);
     if (index == invalid_arg_index) on_error("named argument is not found");
-    return context_.check_arg_id(index), index;
+    return index;
 #else
     (void)id;
     on_error("compile-time checks for named arguments require C++20 support");
@@ -2927,41 +2642,55 @@ class format_string_checker {
 
   FMT_CONSTEXPR auto on_format_specs(int id, const Char* begin, const Char*)
       -> const Char* {
-    context_.advance_to(context_.begin() + (begin - &*context_.begin()));
+    context_.advance_to(begin);
     // id >= 0 check is a workaround for gcc 10 bug (#2065).
     return id >= 0 && id < num_args ? parse_funcs_[id](context_) : begin;
   }
 
   FMT_CONSTEXPR void on_error(const char* message) {
-    context_.on_error(message);
+    throw_format_error(message);
   }
 };
 
+// Reports a compile-time error if S is not a valid format string.
+template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
+FMT_INLINE void check_format_string(const S&) {
+#ifdef FMT_ENFORCE_COMPILE_STRING
+  static_assert(is_compile_string<S>::value,
+                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
+                "FMT_STRING.");
+#endif
+}
 template <typename... Args, typename S,
-          enable_if_t<(is_compile_string<S>::value), int>>
+          FMT_ENABLE_IF(is_compile_string<S>::value)>
 void check_format_string(S format_str) {
-  FMT_CONSTEXPR auto s = to_string_view(format_str);
-  using checker = format_string_checker<typename S::char_type, error_handler,
-                                        remove_cvref_t<Args>...>;
-  FMT_CONSTEXPR bool invalid_format =
-      (parse_format_string<true>(s, checker(s, {})), true);
-  ignore_unused(invalid_format);
+  using char_t = typename S::char_type;
+  FMT_CONSTEXPR auto s = basic_string_view<char_t>(format_str);
+  using checker = format_string_checker<char_t, remove_cvref_t<Args>...>;
+  FMT_CONSTEXPR bool error = (parse_format_string<true>(s, checker(s)), true);
+  ignore_unused(error);
 }
 
+template <typename Char = char> struct vformat_args {
+  using type = basic_format_args<
+      basic_format_context<std::back_insert_iterator<buffer<Char>>, Char>>;
+};
+template <> struct vformat_args<char> { using type = format_args; };
+
+// Use vformat_args and avoid type_identity to keep symbols short.
 template <typename Char>
-void vformat_to(
-    buffer<Char>& buf, basic_string_view<Char> fmt,
-    basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args,
-    locale_ref loc = {});
+void vformat_to(buffer<Char>& buf, basic_string_view<Char> fmt,
+                typename vformat_args<Char>::type args, locale_ref loc = {});
 
 FMT_API void vprint_mojibake(std::FILE*, string_view, format_args);
 #ifndef _WIN32
 inline void vprint_mojibake(std::FILE*, string_view, format_args) {}
 #endif
-FMT_END_DETAIL_NAMESPACE
+}  // namespace detail
+
+FMT_BEGIN_EXPORT
 
-// A formatter specialization for the core types corresponding to detail::type
-// constants.
+// A formatter specialization for natively supported types.
 template <typename T, typename Char>
 struct formatter<T, Char,
                  enable_if_t<detail::type_constant<T, Char>::value !=
@@ -2970,72 +2699,21 @@ struct formatter<T, Char,
   detail::dynamic_format_specs<Char> specs_;
 
  public:
-  // Parses format specifiers stopping either at the end of the range or at the
-  // terminating '}'.
   template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    auto begin = ctx.begin(), end = ctx.end();
-    if (begin == end) return begin;
-    using handler_type = detail::dynamic_specs_handler<ParseContext>;
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> const Char* {
     auto type = detail::type_constant<T, Char>::value;
-    auto checker =
-        detail::specs_checker<handler_type>(handler_type(specs_, ctx), type);
-    auto it = detail::parse_format_specs(begin, end, checker);
-    auto eh = ctx.error_handler();
-    switch (type) {
-    case detail::type::none_type:
-      FMT_ASSERT(false, "invalid argument type");
-      break;
-    case detail::type::bool_type:
-      if (specs_.type == presentation_type::none ||
-          specs_.type == presentation_type::string) {
-        break;
-      }
-      FMT_FALLTHROUGH;
-    case detail::type::int_type:
-    case detail::type::uint_type:
-    case detail::type::long_long_type:
-    case detail::type::ulong_long_type:
-    case detail::type::int128_type:
-    case detail::type::uint128_type:
-      detail::check_int_type_spec(specs_.type, eh);
-      break;
-    case detail::type::char_type:
-      detail::check_char_specs(specs_, eh);
-      break;
-    case detail::type::float_type:
-      if (detail::const_check(FMT_USE_FLOAT))
-        detail::parse_float_type_spec(specs_, eh);
-      else
-        FMT_ASSERT(false, "float support disabled");
-      break;
-    case detail::type::double_type:
-      if (detail::const_check(FMT_USE_DOUBLE))
-        detail::parse_float_type_spec(specs_, eh);
-      else
-        FMT_ASSERT(false, "double support disabled");
-      break;
-    case detail::type::long_double_type:
-      if (detail::const_check(FMT_USE_LONG_DOUBLE))
-        detail::parse_float_type_spec(specs_, eh);
-      else
-        FMT_ASSERT(false, "long double support disabled");
-      break;
-    case detail::type::cstring_type:
-      detail::check_cstring_type_spec(specs_.type, eh);
-      break;
-    case detail::type::string_type:
-      detail::check_string_type_spec(specs_.type, eh);
-      break;
-    case detail::type::pointer_type:
-      detail::check_pointer_type_spec(specs_.type, eh);
-      break;
-    case detail::type::custom_type:
-      // Custom format specifiers are checked in parse functions of
-      // formatter specializations.
-      break;
-    }
-    return it;
+    auto end =
+        detail::parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx, type);
+    if (type == detail::type::char_type) detail::check_char_specs(specs_);
+    return end;
+  }
+
+  template <detail::type U = detail::type_constant<T, Char>::value,
+            FMT_ENABLE_IF(U == detail::type::string_type ||
+                          U == detail::type::cstring_type ||
+                          U == detail::type::char_type)>
+  FMT_CONSTEXPR void set_debug_format(bool set = true) {
+    specs_.type = set ? presentation_type::debug : presentation_type::none;
   }
 
   template <typename FormatContext>
@@ -3043,7 +2721,30 @@ struct formatter<T, Char,
       -> decltype(ctx.out());
 };
 
-template <typename Char> struct basic_runtime { basic_string_view<Char> str; };
+#define FMT_FORMAT_AS(Type, Base)                                        \
+  template <typename Char>                                               \
+  struct formatter<Type, Char> : formatter<Base, Char> {                 \
+    template <typename FormatContext>                                    \
+    auto format(const Type& val, FormatContext& ctx) const               \
+        -> decltype(ctx.out()) {                                         \
+      return formatter<Base, Char>::format(static_cast<Base>(val), ctx); \
+    }                                                                    \
+  }
+
+FMT_FORMAT_AS(signed char, int);
+FMT_FORMAT_AS(unsigned char, unsigned);
+FMT_FORMAT_AS(short, int);
+FMT_FORMAT_AS(unsigned short, unsigned);
+FMT_FORMAT_AS(long, long long);
+FMT_FORMAT_AS(unsigned long, unsigned long long);
+FMT_FORMAT_AS(Char*, const Char*);
+FMT_FORMAT_AS(std::basic_string<Char>, basic_string_view<Char>);
+FMT_FORMAT_AS(std::nullptr_t, const void*);
+FMT_FORMAT_AS(detail::std_string_view<Char>, basic_string_view<Char>);
+
+template <typename Char = char> struct runtime_format_string {
+  basic_string_view<Char> str;
+};
 
 /** A compile-time format string. */
 template <typename Char, typename... Args> class basic_format_string {
@@ -3063,25 +2764,24 @@ template <typename Char, typename... Args> class basic_format_string {
 #ifdef FMT_HAS_CONSTEVAL
     if constexpr (detail::count_named_args<Args...>() ==
                   detail::count_statically_named_args<Args...>()) {
-      using checker = detail::format_string_checker<Char, detail::error_handler,
-                                                    remove_cvref_t<Args>...>;
-      detail::parse_format_string<true>(str_, checker(s, {}));
+      using checker =
+          detail::format_string_checker<Char, remove_cvref_t<Args>...>;
+      detail::parse_format_string<true>(str_, checker(s));
     }
 #else
     detail::check_format_string<Args...>(s);
 #endif
   }
-  basic_format_string(basic_runtime<Char> r) : str_(r.str) {}
+  basic_format_string(runtime_format_string<Char> fmt) : str_(fmt.str) {}
 
   FMT_INLINE operator basic_string_view<Char>() const { return str_; }
+  FMT_INLINE auto get() const -> basic_string_view<Char> { return str_; }
 };
 
 #if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
 // Workaround broken conversion on older gcc.
-template <typename... Args> using format_string = string_view;
-template <typename S> auto runtime(const S& s) -> basic_string_view<char_t<S>> {
-  return s;
-}
+template <typename...> using format_string = string_view;
+inline auto runtime(string_view s) -> string_view { return s; }
 #else
 template <typename... Args>
 using format_string = basic_format_string<char, type_identity_t<Args>...>;
@@ -3095,9 +2795,7 @@ using format_string = basic_format_string<char, type_identity_t<Args>...>;
     fmt::print(fmt::runtime("{:d}"), "I am not a number");
   \endrst
  */
-template <typename S> auto runtime(const S& s) -> basic_runtime<char_t<S>> {
-  return {{s}};
-}
+inline auto runtime(string_view s) -> runtime_format_string<> { return {{s}}; }
 #endif
 
 FMT_API auto vformat(string_view fmt, format_args args) -> std::string;
@@ -3123,10 +2821,9 @@ FMT_NODISCARD FMT_INLINE auto format(format_string<T...> fmt, T&&... args)
 template <typename OutputIt,
           FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, char>::value)>
 auto vformat_to(OutputIt out, string_view fmt, format_args args) -> OutputIt {
-  using detail::get_buffer;
-  auto&& buf = get_buffer<char>(out);
+  auto&& buf = detail::get_buffer<char>(out);
   detail::vformat_to(buf, fmt, args, {});
-  return detail::get_iterator(buf);
+  return detail::get_iterator(buf, out);
 }
 
 /**
@@ -3185,7 +2882,7 @@ template <typename... T>
 FMT_NODISCARD FMT_INLINE auto formatted_size(format_string<T...> fmt,
                                              T&&... args) -> size_t {
   auto buf = detail::counting_buffer<>();
-  detail::vformat_to(buf, string_view(fmt), fmt::make_format_args(args...), {});
+  detail::vformat_to<char>(buf, fmt, fmt::make_format_args(args...), {});
   return buf.count();
 }
 
@@ -3226,7 +2923,25 @@ FMT_INLINE void print(std::FILE* f, format_string<T...> fmt, T&&... args) {
                            : detail::vprint_mojibake(f, fmt, vargs);
 }
 
-FMT_MODULE_EXPORT_END
+/**
+  Formats ``args`` according to specifications in ``fmt`` and writes the
+  output to the file ``f`` followed by a newline.
+ */
+template <typename... T>
+FMT_INLINE void println(std::FILE* f, format_string<T...> fmt, T&&... args) {
+  return fmt::print(f, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+/**
+  Formats ``args`` according to specifications in ``fmt`` and writes the output
+  to ``stdout`` followed by a newline.
+ */
+template <typename... T>
+FMT_INLINE void println(format_string<T...> fmt, T&&... args) {
+  return fmt::println(stdout, fmt, std::forward<T>(args)...);
+}
+
+FMT_END_EXPORT
 FMT_GCC_PRAGMA("GCC pop_options")
 FMT_END_NAMESPACE
 
diff --git a/contrib/fmt/include/fmt/format-inl.h b/contrib/fmt/include/fmt/format-inl.h
index 2c51c50ae..5bae3c7b2 100644
--- a/contrib/fmt/include/fmt/format-inl.h
+++ b/contrib/fmt/include/fmt/format-inl.h
@@ -9,13 +9,9 @@
 #define FMT_FORMAT_INL_H_
 
 #include <algorithm>
-#include <cctype>
 #include <cerrno>  // errno
 #include <climits>
 #include <cmath>
-#include <cstdarg>
-#include <cstring>  // std::memmove
-#include <cwchar>
 #include <exception>
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
@@ -44,21 +40,8 @@ FMT_FUNC void throw_format_error(const char* message) {
   FMT_THROW(format_error(message));
 }
 
-#ifndef _MSC_VER
-#  define FMT_SNPRINTF snprintf
-#else  // _MSC_VER
-inline int fmt_snprintf(char* buffer, size_t size, const char* format, ...) {
-  va_list args;
-  va_start(args, format);
-  int result = vsnprintf_s(buffer, size, _TRUNCATE, format, args);
-  va_end(args);
-  return result;
-}
-#  define FMT_SNPRINTF fmt_snprintf
-#endif  // _MSC_VER
-
 FMT_FUNC void format_error_code(detail::buffer<char>& out, int error_code,
-                                string_view message) FMT_NOEXCEPT {
+                                string_view message) noexcept {
   // Report error code making sure that the output fits into
   // inline_buffer_size to avoid dynamic memory allocation and potential
   // bad_alloc.
@@ -81,7 +64,7 @@ FMT_FUNC void format_error_code(detail::buffer<char>& out, int error_code,
 }
 
 FMT_FUNC void report_error(format_func func, int error_code,
-                           const char* message) FMT_NOEXCEPT {
+                           const char* message) noexcept {
   memory_buffer full_message;
   func(full_message, error_code, message);
   // Don't use fwrite_fully because the latter may throw.
@@ -93,7 +76,8 @@ FMT_FUNC void report_error(format_func func, int error_code,
 inline void fwrite_fully(const void* ptr, size_t size, size_t count,
                          FILE* stream) {
   size_t written = std::fwrite(ptr, size, count, stream);
-  if (written < count) FMT_THROW(system_error(errno, "cannot write to file"));
+  if (written < count)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
 }
 
 #ifndef FMT_STATIC_THOUSANDS_SEPARATOR
@@ -127,928 +111,151 @@ template <typename Char> FMT_FUNC Char decimal_point_impl(locale_ref) {
   return '.';
 }
 #endif
-}  // namespace detail
 
-#if !FMT_MSC_VER
-FMT_API FMT_FUNC format_error::~format_error() FMT_NOEXCEPT = default;
+FMT_FUNC auto write_loc(appender out, loc_value value,
+                        const format_specs<>& specs, locale_ref loc) -> bool {
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+  auto locale = loc.get<std::locale>();
+  // We cannot use the num_put<char> facet because it may produce output in
+  // a wrong encoding.
+  using facet = format_facet<std::locale>;
+  if (std::has_facet<facet>(locale))
+    return std::use_facet<facet>(locale).put(out, value, specs);
+  return facet(locale).put(out, value, specs);
 #endif
-
-FMT_FUNC std::system_error vsystem_error(int error_code, string_view format_str,
-                                         format_args args) {
-  auto ec = std::error_code(error_code, std::generic_category());
-  return std::system_error(ec, vformat(format_str, args));
+  return false;
 }
+}  // namespace detail
 
-namespace detail {
-
-template <> FMT_FUNC int count_digits<4>(detail::fallback_uintptr n) {
-  // fallback_uintptr is always stored in little endian.
-  int i = static_cast<int>(sizeof(void*)) - 1;
-  while (i > 0 && n.value[i] == 0) --i;
-  auto char_digits = std::numeric_limits<unsigned char>::digits / 4;
-  return i >= 0 ? i * char_digits + count_digits<4, unsigned>(n.value[i]) : 1;
-}
-
-// log10(2) = 0x0.4d104d427de7fbcc...
-static constexpr uint64_t log10_2_significand = 0x4d104d427de7fbcc;
-
-template <typename T = void> struct basic_impl_data {
-  // Normalized 64-bit significands of pow(10, k), for k = -348, -340, ..., 340.
-  // These are generated by support/compute-powers.py.
-  static constexpr uint64_t pow10_significands[87] = {
-      0xfa8fd5a0081c0288, 0xbaaee17fa23ebf76, 0x8b16fb203055ac76,
-      0xcf42894a5dce35ea, 0x9a6bb0aa55653b2d, 0xe61acf033d1a45df,
-      0xab70fe17c79ac6ca, 0xff77b1fcbebcdc4f, 0xbe5691ef416bd60c,
-      0x8dd01fad907ffc3c, 0xd3515c2831559a83, 0x9d71ac8fada6c9b5,
-      0xea9c227723ee8bcb, 0xaecc49914078536d, 0x823c12795db6ce57,
-      0xc21094364dfb5637, 0x9096ea6f3848984f, 0xd77485cb25823ac7,
-      0xa086cfcd97bf97f4, 0xef340a98172aace5, 0xb23867fb2a35b28e,
-      0x84c8d4dfd2c63f3b, 0xc5dd44271ad3cdba, 0x936b9fcebb25c996,
-      0xdbac6c247d62a584, 0xa3ab66580d5fdaf6, 0xf3e2f893dec3f126,
-      0xb5b5ada8aaff80b8, 0x87625f056c7c4a8b, 0xc9bcff6034c13053,
-      0x964e858c91ba2655, 0xdff9772470297ebd, 0xa6dfbd9fb8e5b88f,
-      0xf8a95fcf88747d94, 0xb94470938fa89bcf, 0x8a08f0f8bf0f156b,
-      0xcdb02555653131b6, 0x993fe2c6d07b7fac, 0xe45c10c42a2b3b06,
-      0xaa242499697392d3, 0xfd87b5f28300ca0e, 0xbce5086492111aeb,
-      0x8cbccc096f5088cc, 0xd1b71758e219652c, 0x9c40000000000000,
-      0xe8d4a51000000000, 0xad78ebc5ac620000, 0x813f3978f8940984,
-      0xc097ce7bc90715b3, 0x8f7e32ce7bea5c70, 0xd5d238a4abe98068,
-      0x9f4f2726179a2245, 0xed63a231d4c4fb27, 0xb0de65388cc8ada8,
-      0x83c7088e1aab65db, 0xc45d1df942711d9a, 0x924d692ca61be758,
-      0xda01ee641a708dea, 0xa26da3999aef774a, 0xf209787bb47d6b85,
-      0xb454e4a179dd1877, 0x865b86925b9bc5c2, 0xc83553c5c8965d3d,
-      0x952ab45cfa97a0b3, 0xde469fbd99a05fe3, 0xa59bc234db398c25,
-      0xf6c69a72a3989f5c, 0xb7dcbf5354e9bece, 0x88fcf317f22241e2,
-      0xcc20ce9bd35c78a5, 0x98165af37b2153df, 0xe2a0b5dc971f303a,
-      0xa8d9d1535ce3b396, 0xfb9b7cd9a4a7443c, 0xbb764c4ca7a44410,
-      0x8bab8eefb6409c1a, 0xd01fef10a657842c, 0x9b10a4e5e9913129,
-      0xe7109bfba19c0c9d, 0xac2820d9623bf429, 0x80444b5e7aa7cf85,
-      0xbf21e44003acdd2d, 0x8e679c2f5e44ff8f, 0xd433179d9c8cb841,
-      0x9e19db92b4e31ba9, 0xeb96bf6ebadf77d9, 0xaf87023b9bf0ee6b,
-  };
-
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-#  pragma GCC diagnostic push
-#  pragma GCC diagnostic ignored "-Wnarrowing"
-#endif
-  // Binary exponents of pow(10, k), for k = -348, -340, ..., 340, corresponding
-  // to significands above.
-  static constexpr int16_t pow10_exponents[87] = {
-      -1220, -1193, -1166, -1140, -1113, -1087, -1060, -1034, -1007, -980, -954,
-      -927,  -901,  -874,  -847,  -821,  -794,  -768,  -741,  -715,  -688, -661,
-      -635,  -608,  -582,  -555,  -529,  -502,  -475,  -449,  -422,  -396, -369,
-      -343,  -316,  -289,  -263,  -236,  -210,  -183,  -157,  -130,  -103, -77,
-      -50,   -24,   3,     30,    56,    83,    109,   136,   162,   189,  216,
-      242,   269,   295,   322,   348,   375,   402,   428,   455,   481,  508,
-      534,   561,   588,   614,   641,   667,   694,   720,   747,   774,  800,
-      827,   853,   880,   907,   933,   960,   986,   1013,  1039,  1066};
-#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
-#  pragma GCC diagnostic pop
-#endif
-
-  static constexpr uint64_t power_of_10_64[20] = {
-      1, FMT_POWERS_OF_10(1ULL), FMT_POWERS_OF_10(1000000000ULL),
-      10000000000000000000ULL};
-};
-
-// This is a struct rather than an alias to avoid shadowing warnings in gcc.
-struct impl_data : basic_impl_data<> {};
+template <typename Locale> typename Locale::id format_facet<Locale>::id;
 
-#if __cplusplus < 201703L
-template <typename T>
-constexpr uint64_t basic_impl_data<T>::pow10_significands[];
-template <typename T> constexpr int16_t basic_impl_data<T>::pow10_exponents[];
-template <typename T> constexpr uint64_t basic_impl_data<T>::power_of_10_64[];
-#endif
-
-template <typename T> struct bits {
-  static FMT_CONSTEXPR_DECL const int value =
-      static_cast<int>(sizeof(T) * std::numeric_limits<unsigned char>::digits);
-};
-
-// Returns the number of significand bits in Float excluding the implicit bit.
-template <typename Float> constexpr int num_significand_bits() {
-  // Subtract 1 to account for an implicit most significant bit in the
-  // normalized form.
-  return std::numeric_limits<Float>::digits - 1;
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+template <typename Locale> format_facet<Locale>::format_facet(Locale& loc) {
+  auto& numpunct = std::use_facet<std::numpunct<char>>(loc);
+  grouping_ = numpunct.grouping();
+  if (!grouping_.empty()) separator_ = std::string(1, numpunct.thousands_sep());
 }
 
-// A floating-point number f * pow(2, e).
-struct fp {
-  uint64_t f;
-  int e;
-
-  static constexpr const int num_significand_bits = bits<decltype(f)>::value;
-
-  constexpr fp() : f(0), e(0) {}
-  constexpr fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
-
-  // Constructs fp from an IEEE754 floating-point number. It is a template to
-  // prevent compile errors on systems where n is not IEEE754.
-  template <typename Float> explicit FMT_CONSTEXPR fp(Float n) { assign(n); }
-
-  template <typename Float>
-  using is_supported = bool_constant<sizeof(Float) == sizeof(uint64_t) ||
-                                     sizeof(Float) == sizeof(uint32_t)>;
-
-  // Assigns d to this and return true iff predecessor is closer than successor.
-  template <typename Float, FMT_ENABLE_IF(is_supported<Float>::value)>
-  FMT_CONSTEXPR bool assign(Float n) {
-    // Assume float is in the format [sign][exponent][significand].
-    const int num_float_significand_bits =
-        detail::num_significand_bits<Float>();
-    const uint64_t implicit_bit = 1ULL << num_float_significand_bits;
-    const uint64_t significand_mask = implicit_bit - 1;
-    constexpr bool is_double = sizeof(Float) == sizeof(uint64_t);
-    auto u = bit_cast<conditional_t<is_double, uint64_t, uint32_t>>(n);
-    f = u & significand_mask;
-    const uint64_t exponent_mask = (~0ULL >> 1) & ~significand_mask;
-    int biased_e =
-        static_cast<int>((u & exponent_mask) >> num_float_significand_bits);
-    // The predecessor is closer if n is a normalized power of 2 (f == 0) other
-    // than the smallest normalized number (biased_e > 1).
-    bool is_predecessor_closer = f == 0 && biased_e > 1;
-    if (biased_e != 0)
-      f += implicit_bit;
-    else
-      biased_e = 1;  // Subnormals use biased exponent 1 (min exponent).
-    const int exponent_bias = std::numeric_limits<Float>::max_exponent - 1;
-    e = biased_e - exponent_bias - num_float_significand_bits;
-    return is_predecessor_closer;
-  }
-
-  template <typename Float, FMT_ENABLE_IF(!is_supported<Float>::value)>
-  bool assign(Float) {
-    FMT_ASSERT(false, "");
-    return false;
-  }
-};
-
-// Normalizes the value converted from double and multiplied by (1 << SHIFT).
-template <int SHIFT = 0> FMT_CONSTEXPR fp normalize(fp value) {
-  // Handle subnormals.
-  const uint64_t implicit_bit = 1ULL << num_significand_bits<double>();
-  const auto shifted_implicit_bit = implicit_bit << SHIFT;
-  while ((value.f & shifted_implicit_bit) == 0) {
-    value.f <<= 1;
-    --value.e;
-  }
-  // Subtract 1 to account for hidden bit.
-  const auto offset =
-      fp::num_significand_bits - num_significand_bits<double>() - SHIFT - 1;
-  value.f <<= offset;
-  value.e -= offset;
-  return value;
+template <>
+FMT_API FMT_FUNC auto format_facet<std::locale>::do_put(
+    appender out, loc_value val, const format_specs<>& specs) const -> bool {
+  return val.visit(
+      detail::loc_writer<>{out, specs, separator_, grouping_, decimal_point_});
 }
-
-inline bool operator==(fp x, fp y) { return x.f == y.f && x.e == y.e; }
-
-// Computes lhs * rhs / pow(2, 64) rounded to nearest with half-up tie breaking.
-FMT_CONSTEXPR inline uint64_t multiply(uint64_t lhs, uint64_t rhs) {
-#if FMT_USE_INT128
-  auto product = static_cast<__uint128_t>(lhs) * rhs;
-  auto f = static_cast<uint64_t>(product >> 64);
-  return (static_cast<uint64_t>(product) & (1ULL << 63)) != 0 ? f + 1 : f;
-#else
-  // Multiply 32-bit parts of significands.
-  uint64_t mask = (1ULL << 32) - 1;
-  uint64_t a = lhs >> 32, b = lhs & mask;
-  uint64_t c = rhs >> 32, d = rhs & mask;
-  uint64_t ac = a * c, bc = b * c, ad = a * d, bd = b * d;
-  // Compute mid 64-bit of result and round.
-  uint64_t mid = (bd >> 32) + (ad & mask) + (bc & mask) + (1U << 31);
-  return ac + (ad >> 32) + (bc >> 32) + (mid >> 32);
 #endif
-}
 
-FMT_CONSTEXPR inline fp operator*(fp x, fp y) {
-  return {multiply(x.f, y.f), x.e + y.e + 64};
-}
-
-// Returns a cached power of 10 `c_k = c_k.f * pow(2, c_k.e)` such that its
-// (binary) exponent satisfies `min_exponent <= c_k.e <= min_exponent + 28`.
-FMT_CONSTEXPR inline fp get_cached_power(int min_exponent,
-                                         int& pow10_exponent) {
-  const int shift = 32;
-  const auto significand = static_cast<int64_t>(log10_2_significand);
-  int index = static_cast<int>(
-      ((min_exponent + fp::num_significand_bits - 1) * (significand >> shift) +
-       ((int64_t(1) << shift) - 1))  // ceil
-      >> 32                          // arithmetic shift
-  );
-  // Decimal exponent of the first (smallest) cached power of 10.
-  const int first_dec_exp = -348;
-  // Difference between 2 consecutive decimal exponents in cached powers of 10.
-  const int dec_exp_step = 8;
-  index = (index - first_dec_exp - 1) / dec_exp_step + 1;
-  pow10_exponent = first_dec_exp + index * dec_exp_step;
-  return {impl_data::pow10_significands[index],
-          impl_data::pow10_exponents[index]};
+FMT_FUNC std::system_error vsystem_error(int error_code, string_view fmt,
+                                         format_args args) {
+  auto ec = std::error_code(error_code, std::generic_category());
+  return std::system_error(ec, vformat(fmt, args));
 }
 
-// A simple accumulator to hold the sums of terms in bigint::square if uint128_t
-// is not available.
-struct accumulator {
-  uint64_t lower;
-  uint64_t upper;
-
-  constexpr accumulator() : lower(0), upper(0) {}
-  constexpr explicit operator uint32_t() const {
-    return static_cast<uint32_t>(lower);
-  }
-
-  FMT_CONSTEXPR void operator+=(uint64_t n) {
-    lower += n;
-    if (lower < n) ++upper;
-  }
-  FMT_CONSTEXPR void operator>>=(int shift) {
-    FMT_ASSERT(shift == 32, "");
-    (void)shift;
-    lower = (upper << 32) | (lower >> 32);
-    upper >>= 32;
-  }
-};
-
-class bigint {
- private:
-  // A bigint is stored as an array of bigits (big digits), with bigit at index
-  // 0 being the least significant one.
-  using bigit = uint32_t;
-  using double_bigit = uint64_t;
-  enum { bigits_capacity = 32 };
-  basic_memory_buffer<bigit, bigits_capacity> bigits_;
-  int exp_;
-
-  FMT_CONSTEXPR20 bigit operator[](int index) const {
-    return bigits_[to_unsigned(index)];
-  }
-  FMT_CONSTEXPR20 bigit& operator[](int index) {
-    return bigits_[to_unsigned(index)];
-  }
-
-  static FMT_CONSTEXPR_DECL const int bigit_bits = bits<bigit>::value;
-
-  friend struct formatter<bigint>;
-
-  FMT_CONSTEXPR20 void subtract_bigits(int index, bigit other, bigit& borrow) {
-    auto result = static_cast<double_bigit>((*this)[index]) - other - borrow;
-    (*this)[index] = static_cast<bigit>(result);
-    borrow = static_cast<bigit>(result >> (bigit_bits * 2 - 1));
-  }
-
-  FMT_CONSTEXPR20 void remove_leading_zeros() {
-    int num_bigits = static_cast<int>(bigits_.size()) - 1;
-    while (num_bigits > 0 && (*this)[num_bigits] == 0) --num_bigits;
-    bigits_.resize(to_unsigned(num_bigits + 1));
-  }
-
-  // Computes *this -= other assuming aligned bigints and *this >= other.
-  FMT_CONSTEXPR20 void subtract_aligned(const bigint& other) {
-    FMT_ASSERT(other.exp_ >= exp_, "unaligned bigints");
-    FMT_ASSERT(compare(*this, other) >= 0, "");
-    bigit borrow = 0;
-    int i = other.exp_ - exp_;
-    for (size_t j = 0, n = other.bigits_.size(); j != n; ++i, ++j)
-      subtract_bigits(i, other.bigits_[j], borrow);
-    while (borrow > 0) subtract_bigits(i, 0, borrow);
-    remove_leading_zeros();
-  }
-
-  FMT_CONSTEXPR20 void multiply(uint32_t value) {
-    const double_bigit wide_value = value;
-    bigit carry = 0;
-    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
-      double_bigit result = bigits_[i] * wide_value + carry;
-      bigits_[i] = static_cast<bigit>(result);
-      carry = static_cast<bigit>(result >> bigit_bits);
-    }
-    if (carry != 0) bigits_.push_back(carry);
-  }
-
-  FMT_CONSTEXPR20 void multiply(uint64_t value) {
-    const bigit mask = ~bigit(0);
-    const double_bigit lower = value & mask;
-    const double_bigit upper = value >> bigit_bits;
-    double_bigit carry = 0;
-    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
-      double_bigit result = bigits_[i] * lower + (carry & mask);
-      carry =
-          bigits_[i] * upper + (result >> bigit_bits) + (carry >> bigit_bits);
-      bigits_[i] = static_cast<bigit>(result);
-    }
-    while (carry != 0) {
-      bigits_.push_back(carry & mask);
-      carry >>= bigit_bits;
-    }
-  }
-
- public:
-  FMT_CONSTEXPR20 bigint() : exp_(0) {}
-  explicit bigint(uint64_t n) { assign(n); }
-  FMT_CONSTEXPR20 ~bigint() {
-    FMT_ASSERT(bigits_.capacity() <= bigits_capacity, "");
-  }
-
-  bigint(const bigint&) = delete;
-  void operator=(const bigint&) = delete;
-
-  FMT_CONSTEXPR20 void assign(const bigint& other) {
-    auto size = other.bigits_.size();
-    bigits_.resize(size);
-    auto data = other.bigits_.data();
-    std::copy(data, data + size, make_checked(bigits_.data(), size));
-    exp_ = other.exp_;
-  }
-
-  FMT_CONSTEXPR20 void assign(uint64_t n) {
-    size_t num_bigits = 0;
-    do {
-      bigits_[num_bigits++] = n & ~bigit(0);
-      n >>= bigit_bits;
-    } while (n != 0);
-    bigits_.resize(num_bigits);
-    exp_ = 0;
-  }
-
-  FMT_CONSTEXPR20 int num_bigits() const {
-    return static_cast<int>(bigits_.size()) + exp_;
-  }
-
-  FMT_NOINLINE FMT_CONSTEXPR20 bigint& operator<<=(int shift) {
-    FMT_ASSERT(shift >= 0, "");
-    exp_ += shift / bigit_bits;
-    shift %= bigit_bits;
-    if (shift == 0) return *this;
-    bigit carry = 0;
-    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
-      bigit c = bigits_[i] >> (bigit_bits - shift);
-      bigits_[i] = (bigits_[i] << shift) + carry;
-      carry = c;
-    }
-    if (carry != 0) bigits_.push_back(carry);
-    return *this;
-  }
-
-  template <typename Int> FMT_CONSTEXPR20 bigint& operator*=(Int value) {
-    FMT_ASSERT(value > 0, "");
-    multiply(uint32_or_64_or_128_t<Int>(value));
-    return *this;
-  }
-
-  friend FMT_CONSTEXPR20 int compare(const bigint& lhs, const bigint& rhs) {
-    int num_lhs_bigits = lhs.num_bigits(), num_rhs_bigits = rhs.num_bigits();
-    if (num_lhs_bigits != num_rhs_bigits)
-      return num_lhs_bigits > num_rhs_bigits ? 1 : -1;
-    int i = static_cast<int>(lhs.bigits_.size()) - 1;
-    int j = static_cast<int>(rhs.bigits_.size()) - 1;
-    int end = i - j;
-    if (end < 0) end = 0;
-    for (; i >= end; --i, --j) {
-      bigit lhs_bigit = lhs[i], rhs_bigit = rhs[j];
-      if (lhs_bigit != rhs_bigit) return lhs_bigit > rhs_bigit ? 1 : -1;
-    }
-    if (i != j) return i > j ? 1 : -1;
-    return 0;
-  }
-
-  // Returns compare(lhs1 + lhs2, rhs).
-  friend FMT_CONSTEXPR20 int add_compare(const bigint& lhs1, const bigint& lhs2,
-                                         const bigint& rhs) {
-    int max_lhs_bigits = (std::max)(lhs1.num_bigits(), lhs2.num_bigits());
-    int num_rhs_bigits = rhs.num_bigits();
-    if (max_lhs_bigits + 1 < num_rhs_bigits) return -1;
-    if (max_lhs_bigits > num_rhs_bigits) return 1;
-    auto get_bigit = [](const bigint& n, int i) -> bigit {
-      return i >= n.exp_ && i < n.num_bigits() ? n[i - n.exp_] : 0;
-    };
-    double_bigit borrow = 0;
-    int min_exp = (std::min)((std::min)(lhs1.exp_, lhs2.exp_), rhs.exp_);
-    for (int i = num_rhs_bigits - 1; i >= min_exp; --i) {
-      double_bigit sum =
-          static_cast<double_bigit>(get_bigit(lhs1, i)) + get_bigit(lhs2, i);
-      bigit rhs_bigit = get_bigit(rhs, i);
-      if (sum > rhs_bigit + borrow) return 1;
-      borrow = rhs_bigit + borrow - sum;
-      if (borrow > 1) return -1;
-      borrow <<= bigit_bits;
-    }
-    return borrow != 0 ? -1 : 0;
-  }
-
-  // Assigns pow(10, exp) to this bigint.
-  FMT_CONSTEXPR20 void assign_pow10(int exp) {
-    FMT_ASSERT(exp >= 0, "");
-    if (exp == 0) return assign(1);
-    // Find the top bit.
-    int bitmask = 1;
-    while (exp >= bitmask) bitmask <<= 1;
-    bitmask >>= 1;
-    // pow(10, exp) = pow(5, exp) * pow(2, exp). First compute pow(5, exp) by
-    // repeated squaring and multiplication.
-    assign(5);
-    bitmask >>= 1;
-    while (bitmask != 0) {
-      square();
-      if ((exp & bitmask) != 0) *this *= 5;
-      bitmask >>= 1;
-    }
-    *this <<= exp;  // Multiply by pow(2, exp) by shifting.
-  }
-
-  FMT_CONSTEXPR20 void square() {
-    int num_bigits = static_cast<int>(bigits_.size());
-    int num_result_bigits = 2 * num_bigits;
-    basic_memory_buffer<bigit, bigits_capacity> n(std::move(bigits_));
-    bigits_.resize(to_unsigned(num_result_bigits));
-    using accumulator_t = conditional_t<FMT_USE_INT128, uint128_t, accumulator>;
-    auto sum = accumulator_t();
-    for (int bigit_index = 0; bigit_index < num_bigits; ++bigit_index) {
-      // Compute bigit at position bigit_index of the result by adding
-      // cross-product terms n[i] * n[j] such that i + j == bigit_index.
-      for (int i = 0, j = bigit_index; j >= 0; ++i, --j) {
-        // Most terms are multiplied twice which can be optimized in the future.
-        sum += static_cast<double_bigit>(n[i]) * n[j];
-      }
-      (*this)[bigit_index] = static_cast<bigit>(sum);
-      sum >>= bits<bigit>::value;  // Compute the carry.
-    }
-    // Do the same for the top half.
-    for (int bigit_index = num_bigits; bigit_index < num_result_bigits;
-         ++bigit_index) {
-      for (int j = num_bigits - 1, i = bigit_index - j; i < num_bigits;)
-        sum += static_cast<double_bigit>(n[i++]) * n[j--];
-      (*this)[bigit_index] = static_cast<bigit>(sum);
-      sum >>= bits<bigit>::value;
-    }
-    remove_leading_zeros();
-    exp_ *= 2;
-  }
-
-  // If this bigint has a bigger exponent than other, adds trailing zero to make
-  // exponents equal. This simplifies some operations such as subtraction.
-  FMT_CONSTEXPR20 void align(const bigint& other) {
-    int exp_difference = exp_ - other.exp_;
-    if (exp_difference <= 0) return;
-    int num_bigits = static_cast<int>(bigits_.size());
-    bigits_.resize(to_unsigned(num_bigits + exp_difference));
-    for (int i = num_bigits - 1, j = i + exp_difference; i >= 0; --i, --j)
-      bigits_[j] = bigits_[i];
-    std::uninitialized_fill_n(bigits_.data(), exp_difference, 0);
-    exp_ -= exp_difference;
-  }
-
-  // Divides this bignum by divisor, assigning the remainder to this and
-  // returning the quotient.
-  FMT_CONSTEXPR20 int divmod_assign(const bigint& divisor) {
-    FMT_ASSERT(this != &divisor, "");
-    if (compare(*this, divisor) < 0) return 0;
-    FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1u] != 0, "");
-    align(divisor);
-    int quotient = 0;
-    do {
-      subtract_aligned(divisor);
-      ++quotient;
-    } while (compare(*this, divisor) >= 0);
-    return quotient;
-  }
-};
+namespace detail {
 
-enum class round_direction { unknown, up, down };
-
-// Given the divisor (normally a power of 10), the remainder = v % divisor for
-// some number v and the error, returns whether v should be rounded up, down, or
-// whether the rounding direction can't be determined due to error.
-// error should be less than divisor / 2.
-FMT_CONSTEXPR inline round_direction get_round_direction(uint64_t divisor,
-                                                         uint64_t remainder,
-                                                         uint64_t error) {
-  FMT_ASSERT(remainder < divisor, "");  // divisor - remainder won't overflow.
-  FMT_ASSERT(error < divisor, "");      // divisor - error won't overflow.
-  FMT_ASSERT(error < divisor - error, "");  // error * 2 won't overflow.
-  // Round down if (remainder + error) * 2 <= divisor.
-  if (remainder <= divisor - remainder && error * 2 <= divisor - remainder * 2)
-    return round_direction::down;
-  // Round up if (remainder - error) * 2 >= divisor.
-  if (remainder >= error &&
-      remainder - error >= divisor - (remainder - error)) {
-    return round_direction::up;
-  }
-  return round_direction::unknown;
+template <typename F> inline bool operator==(basic_fp<F> x, basic_fp<F> y) {
+  return x.f == y.f && x.e == y.e;
 }
 
-namespace digits {
-enum result {
-  more,  // Generate more digits.
-  done,  // Done generating digits.
-  error  // Digit generation cancelled due to an error.
-};
+// Compilers should be able to optimize this into the ror instruction.
+FMT_CONSTEXPR inline uint32_t rotr(uint32_t n, uint32_t r) noexcept {
+  r &= 31;
+  return (n >> r) | (n << (32 - r));
 }
-
-struct gen_digits_handler {
-  char* buf;
-  int size;
-  int precision;
-  int exp10;
-  bool fixed;
-
-  FMT_CONSTEXPR digits::result on_digit(char digit, uint64_t divisor,
-                                        uint64_t remainder, uint64_t error,
-                                        bool integral) {
-    FMT_ASSERT(remainder < divisor, "");
-    buf[size++] = digit;
-    if (!integral && error >= remainder) return digits::error;
-    if (size < precision) return digits::more;
-    if (!integral) {
-      // Check if error * 2 < divisor with overflow prevention.
-      // The check is not needed for the integral part because error = 1
-      // and divisor > (1 << 32) there.
-      if (error >= divisor || error >= divisor - error) return digits::error;
-    } else {
-      FMT_ASSERT(error == 1 && divisor > 2, "");
-    }
-    auto dir = get_round_direction(divisor, remainder, error);
-    if (dir != round_direction::up)
-      return dir == round_direction::down ? digits::done : digits::error;
-    ++buf[size - 1];
-    for (int i = size - 1; i > 0 && buf[i] > '9'; --i) {
-      buf[i] = '0';
-      ++buf[i - 1];
-    }
-    if (buf[0] > '9') {
-      buf[0] = '1';
-      if (fixed)
-        buf[size++] = '0';
-      else
-        ++exp10;
-    }
-    return digits::done;
-  }
-};
-
-// Generates output using the Grisu digit-gen algorithm.
-// error: the size of the region (lower, upper) outside of which numbers
-// definitely do not round to value (Delta in Grisu3).
-FMT_INLINE FMT_CONSTEXPR20 digits::result grisu_gen_digits(
-    fp value, uint64_t error, int& exp, gen_digits_handler& handler) {
-  const fp one(1ULL << -value.e, value.e);
-  // The integral part of scaled value (p1 in Grisu) = value / one. It cannot be
-  // zero because it contains a product of two 64-bit numbers with MSB set (due
-  // to normalization) - 1, shifted right by at most 60 bits.
-  auto integral = static_cast<uint32_t>(value.f >> -one.e);
-  FMT_ASSERT(integral != 0, "");
-  FMT_ASSERT(integral == value.f >> -one.e, "");
-  // The fractional part of scaled value (p2 in Grisu) c = value % one.
-  uint64_t fractional = value.f & (one.f - 1);
-  exp = count_digits(integral);  // kappa in Grisu.
-  // Non-fixed formats require at least one digit and no precision adjustment.
-  if (handler.fixed) {
-    // Adjust fixed precision by exponent because it is relative to decimal
-    // point.
-    int precision_offset = exp + handler.exp10;
-    if (precision_offset > 0 &&
-        handler.precision > max_value<int>() - precision_offset) {
-      FMT_THROW(format_error("number is too big"));
-    }
-    handler.precision += precision_offset;
-    // Check if precision is satisfied just by leading zeros, e.g.
-    // format("{:.2f}", 0.001) gives "0.00" without generating any digits.
-    if (handler.precision <= 0) {
-      if (handler.precision < 0) return digits::done;
-      // Divide by 10 to prevent overflow.
-      uint64_t divisor = impl_data::power_of_10_64[exp - 1] << -one.e;
-      auto dir = get_round_direction(divisor, value.f / 10, error * 10);
-      if (dir == round_direction::unknown) return digits::error;
-      handler.buf[handler.size++] = dir == round_direction::up ? '1' : '0';
-      return digits::done;
-    }
-  }
-  // Generate digits for the integral part. This can produce up to 10 digits.
-  do {
-    uint32_t digit = 0;
-    auto divmod_integral = [&](uint32_t divisor) {
-      digit = integral / divisor;
-      integral %= divisor;
-    };
-    // This optimization by Milo Yip reduces the number of integer divisions by
-    // one per iteration.
-    switch (exp) {
-    case 10:
-      divmod_integral(1000000000);
-      break;
-    case 9:
-      divmod_integral(100000000);
-      break;
-    case 8:
-      divmod_integral(10000000);
-      break;
-    case 7:
-      divmod_integral(1000000);
-      break;
-    case 6:
-      divmod_integral(100000);
-      break;
-    case 5:
-      divmod_integral(10000);
-      break;
-    case 4:
-      divmod_integral(1000);
-      break;
-    case 3:
-      divmod_integral(100);
-      break;
-    case 2:
-      divmod_integral(10);
-      break;
-    case 1:
-      digit = integral;
-      integral = 0;
-      break;
-    default:
-      FMT_ASSERT(false, "invalid number of digits");
-    }
-    --exp;
-    auto remainder = (static_cast<uint64_t>(integral) << -one.e) + fractional;
-    auto result = handler.on_digit(static_cast<char>('0' + digit),
-                                   impl_data::power_of_10_64[exp] << -one.e,
-                                   remainder, error, true);
-    if (result != digits::more) return result;
-  } while (exp > 0);
-  // Generate digits for the fractional part.
-  for (;;) {
-    fractional *= 10;
-    error *= 10;
-    char digit = static_cast<char>('0' + (fractional >> -one.e));
-    fractional &= one.f - 1;
-    --exp;
-    auto result = handler.on_digit(digit, one.f, fractional, error, false);
-    if (result != digits::more) return result;
-  }
+FMT_CONSTEXPR inline uint64_t rotr(uint64_t n, uint32_t r) noexcept {
+  r &= 63;
+  return (n >> r) | (n << (64 - r));
 }
 
-// A 128-bit integer type used internally,
-struct uint128_wrapper {
-  uint128_wrapper() = default;
-
-#if FMT_USE_INT128
-  uint128_t internal_;
-
-  constexpr uint128_wrapper(uint64_t high, uint64_t low) FMT_NOEXCEPT
-      : internal_{static_cast<uint128_t>(low) |
-                  (static_cast<uint128_t>(high) << 64)} {}
-
-  constexpr uint128_wrapper(uint128_t u) : internal_{u} {}
-
-  constexpr uint64_t high() const FMT_NOEXCEPT {
-    return uint64_t(internal_ >> 64);
-  }
-  constexpr uint64_t low() const FMT_NOEXCEPT { return uint64_t(internal_); }
-
-  uint128_wrapper& operator+=(uint64_t n) FMT_NOEXCEPT {
-    internal_ += n;
-    return *this;
-  }
-#else
-  uint64_t high_;
-  uint64_t low_;
-
-  constexpr uint128_wrapper(uint64_t high, uint64_t low) FMT_NOEXCEPT
-      : high_{high},
-        low_{low} {}
-
-  constexpr uint64_t high() const FMT_NOEXCEPT { return high_; }
-  constexpr uint64_t low() const FMT_NOEXCEPT { return low_; }
-
-  uint128_wrapper& operator+=(uint64_t n) FMT_NOEXCEPT {
-#  if defined(_MSC_VER) && defined(_M_X64)
-    unsigned char carry = _addcarry_u64(0, low_, n, &low_);
-    _addcarry_u64(carry, high_, 0, &high_);
-    return *this;
-#  else
-    uint64_t sum = low_ + n;
-    high_ += (sum < low_ ? 1 : 0);
-    low_ = sum;
-    return *this;
-#  endif
-  }
-#endif
-};
-
 // Implementation of Dragonbox algorithm: https://github.com/jk-jeon/dragonbox.
 namespace dragonbox {
-// Computes 128-bit result of multiplication of two 64-bit unsigned integers.
-inline uint128_wrapper umul128(uint64_t x, uint64_t y) FMT_NOEXCEPT {
-#if FMT_USE_INT128
-  return static_cast<uint128_t>(x) * static_cast<uint128_t>(y);
-#elif defined(_MSC_VER) && defined(_M_X64)
-  uint128_wrapper result;
-  result.low_ = _umul128(x, y, &result.high_);
-  return result;
-#else
-  const uint64_t mask = (uint64_t(1) << 32) - uint64_t(1);
-
-  uint64_t a = x >> 32;
-  uint64_t b = x & mask;
-  uint64_t c = y >> 32;
-  uint64_t d = y & mask;
-
-  uint64_t ac = a * c;
-  uint64_t bc = b * c;
-  uint64_t ad = a * d;
-  uint64_t bd = b * d;
-
-  uint64_t intermediate = (bd >> 32) + (ad & mask) + (bc & mask);
-
-  return {ac + (intermediate >> 32) + (ad >> 32) + (bc >> 32),
-          (intermediate << 32) + (bd & mask)};
-#endif
-}
-
-// Computes upper 64 bits of multiplication of two 64-bit unsigned integers.
-inline uint64_t umul128_upper64(uint64_t x, uint64_t y) FMT_NOEXCEPT {
-#if FMT_USE_INT128
-  auto p = static_cast<uint128_t>(x) * static_cast<uint128_t>(y);
-  return static_cast<uint64_t>(p >> 64);
-#elif defined(_MSC_VER) && defined(_M_X64)
-  return __umulh(x, y);
-#else
-  return umul128(x, y).high();
-#endif
-}
-
-// Computes upper 64 bits of multiplication of a 64-bit unsigned integer and a
-// 128-bit unsigned integer.
-inline uint64_t umul192_upper64(uint64_t x, uint128_wrapper y) FMT_NOEXCEPT {
-  uint128_wrapper g0 = umul128(x, y.high());
-  g0 += umul128_upper64(x, y.low());
-  return g0.high();
-}
-
-// Computes upper 32 bits of multiplication of a 32-bit unsigned integer and a
+// Computes upper 64 bits of multiplication of a 32-bit unsigned integer and a
 // 64-bit unsigned integer.
-inline uint32_t umul96_upper32(uint32_t x, uint64_t y) FMT_NOEXCEPT {
-  return static_cast<uint32_t>(umul128_upper64(x, y));
+inline uint64_t umul96_upper64(uint32_t x, uint64_t y) noexcept {
+  return umul128_upper64(static_cast<uint64_t>(x) << 32, y);
 }
 
-// Computes middle 64 bits of multiplication of a 64-bit unsigned integer and a
+// Computes lower 128 bits of multiplication of a 64-bit unsigned integer and a
 // 128-bit unsigned integer.
-inline uint64_t umul192_middle64(uint64_t x, uint128_wrapper y) FMT_NOEXCEPT {
-  uint64_t g01 = x * y.high();
-  uint64_t g10 = umul128_upper64(x, y.low());
-  return g01 + g10;
+inline uint128_fallback umul192_lower128(uint64_t x,
+                                         uint128_fallback y) noexcept {
+  uint64_t high = x * y.high();
+  uint128_fallback high_low = umul128(x, y.low());
+  return {high + high_low.high(), high_low.low()};
 }
 
 // Computes lower 64 bits of multiplication of a 32-bit unsigned integer and a
 // 64-bit unsigned integer.
-inline uint64_t umul96_lower64(uint32_t x, uint64_t y) FMT_NOEXCEPT {
+inline uint64_t umul96_lower64(uint32_t x, uint64_t y) noexcept {
   return x * y;
 }
 
-// Computes floor(log10(pow(2, e))) for e in [-1700, 1700] using the method from
-// https://fmt.dev/papers/Grisu-Exact.pdf#page=5, section 3.4.
-inline int floor_log10_pow2(int e) FMT_NOEXCEPT {
-  FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent");
-  const int shift = 22;
-  return (e * static_cast<int>(log10_2_significand >> (64 - shift))) >> shift;
-}
-
 // Various fast log computations.
-inline int floor_log2_pow10(int e) FMT_NOEXCEPT {
-  FMT_ASSERT(e <= 1233 && e >= -1233, "too large exponent");
-  const uint64_t log2_10_integer_part = 3;
-  const uint64_t log2_10_fractional_digits = 0x5269e12f346e2bf9;
-  const int shift_amount = 19;
-  return (e * static_cast<int>(
-                  (log2_10_integer_part << shift_amount) |
-                  (log2_10_fractional_digits >> (64 - shift_amount)))) >>
-         shift_amount;
-}
-inline int floor_log10_pow2_minus_log10_4_over_3(int e) FMT_NOEXCEPT {
-  FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent");
-  const uint64_t log10_4_over_3_fractional_digits = 0x1ffbfc2bbc780375;
-  const int shift_amount = 22;
-  return (e * static_cast<int>(log10_2_significand >> (64 - shift_amount)) -
-          static_cast<int>(log10_4_over_3_fractional_digits >>
-                           (64 - shift_amount))) >>
-         shift_amount;
+inline int floor_log10_pow2_minus_log10_4_over_3(int e) noexcept {
+  FMT_ASSERT(e <= 2936 && e >= -2985, "too large exponent");
+  return (e * 631305 - 261663) >> 21;
 }
 
-// Returns true iff x is divisible by pow(2, exp).
-inline bool divisible_by_power_of_2(uint32_t x, int exp) FMT_NOEXCEPT {
-  FMT_ASSERT(exp >= 1, "");
-  FMT_ASSERT(x != 0, "");
-#ifdef FMT_BUILTIN_CTZ
-  return FMT_BUILTIN_CTZ(x) >= exp;
-#else
-  return exp < num_bits<uint32_t>() && x == ((x >> exp) << exp);
-#endif
-}
-inline bool divisible_by_power_of_2(uint64_t x, int exp) FMT_NOEXCEPT {
-  FMT_ASSERT(exp >= 1, "");
-  FMT_ASSERT(x != 0, "");
-#ifdef FMT_BUILTIN_CTZLL
-  return FMT_BUILTIN_CTZLL(x) >= exp;
-#else
-  return exp < num_bits<uint64_t>() && x == ((x >> exp) << exp);
-#endif
-}
-
-// Table entry type for divisibility test.
-template <typename T> struct divtest_table_entry {
-  T mod_inv;
-  T max_quotient;
-};
+FMT_INLINE_VARIABLE constexpr struct {
+  uint32_t divisor;
+  int shift_amount;
+} div_small_pow10_infos[] = {{10, 16}, {100, 16}};
 
-// Returns true iff x is divisible by pow(5, exp).
-inline bool divisible_by_power_of_5(uint32_t x, int exp) FMT_NOEXCEPT {
-  FMT_ASSERT(exp <= 10, "too large exponent");
-  static constexpr const divtest_table_entry<uint32_t> divtest_table[] = {
-      {0x00000001, 0xffffffff}, {0xcccccccd, 0x33333333},
-      {0xc28f5c29, 0x0a3d70a3}, {0x26e978d5, 0x020c49ba},
-      {0x3afb7e91, 0x0068db8b}, {0x0bcbe61d, 0x0014f8b5},
-      {0x68c26139, 0x000431bd}, {0xae8d46a5, 0x0000d6bf},
-      {0x22e90e21, 0x00002af3}, {0x3a2e9c6d, 0x00000897},
-      {0x3ed61f49, 0x000001b7}};
-  return x * divtest_table[exp].mod_inv <= divtest_table[exp].max_quotient;
-}
-inline bool divisible_by_power_of_5(uint64_t x, int exp) FMT_NOEXCEPT {
-  FMT_ASSERT(exp <= 23, "too large exponent");
-  static constexpr const divtest_table_entry<uint64_t> divtest_table[] = {
-      {0x0000000000000001, 0xffffffffffffffff},
-      {0xcccccccccccccccd, 0x3333333333333333},
-      {0x8f5c28f5c28f5c29, 0x0a3d70a3d70a3d70},
-      {0x1cac083126e978d5, 0x020c49ba5e353f7c},
-      {0xd288ce703afb7e91, 0x0068db8bac710cb2},
-      {0x5d4e8fb00bcbe61d, 0x0014f8b588e368f0},
-      {0x790fb65668c26139, 0x000431bde82d7b63},
-      {0xe5032477ae8d46a5, 0x0000d6bf94d5e57a},
-      {0xc767074b22e90e21, 0x00002af31dc46118},
-      {0x8e47ce423a2e9c6d, 0x0000089705f4136b},
-      {0x4fa7f60d3ed61f49, 0x000001b7cdfd9d7b},
-      {0x0fee64690c913975, 0x00000057f5ff85e5},
-      {0x3662e0e1cf503eb1, 0x000000119799812d},
-      {0xa47a2cf9f6433fbd, 0x0000000384b84d09},
-      {0x54186f653140a659, 0x00000000b424dc35},
-      {0x7738164770402145, 0x0000000024075f3d},
-      {0xe4a4d1417cd9a041, 0x000000000734aca5},
-      {0xc75429d9e5c5200d, 0x000000000170ef54},
-      {0xc1773b91fac10669, 0x000000000049c977},
-      {0x26b172506559ce15, 0x00000000000ec1e4},
-      {0xd489e3a9addec2d1, 0x000000000002f394},
-      {0x90e860bb892c8d5d, 0x000000000000971d},
-      {0x502e79bf1b6f4f79, 0x0000000000001e39},
-      {0xdcd618596be30fe5, 0x000000000000060b}};
-  return x * divtest_table[exp].mod_inv <= divtest_table[exp].max_quotient;
-}
-
-// Replaces n by floor(n / pow(5, N)) returning true if and only if n is
-// divisible by pow(5, N).
-// Precondition: n <= 2 * pow(5, N + 1).
+// Replaces n by floor(n / pow(10, N)) returning true if and only if n is
+// divisible by pow(10, N).
+// Precondition: n <= pow(10, N + 1).
 template <int N>
-bool check_divisibility_and_divide_by_pow5(uint32_t& n) FMT_NOEXCEPT {
-  static constexpr struct {
-    uint32_t magic_number;
-    int bits_for_comparison;
-    uint32_t threshold;
-    int shift_amount;
-  } infos[] = {{0xcccd, 16, 0x3333, 18}, {0xa429, 8, 0x0a, 20}};
-  constexpr auto info = infos[N - 1];
-  n *= info.magic_number;
-  const uint32_t comparison_mask = (1u << info.bits_for_comparison) - 1;
-  bool result = (n & comparison_mask) <= info.threshold;
+bool check_divisibility_and_divide_by_pow10(uint32_t& n) noexcept {
+  // The numbers below are chosen such that:
+  //   1. floor(n/d) = floor(nm / 2^k) where d=10 or d=100,
+  //   2. nm mod 2^k < m if and only if n is divisible by d,
+  // where m is magic_number, k is shift_amount
+  // and d is divisor.
+  //
+  // Item 1 is a common technique of replacing division by a constant with
+  // multiplication, see e.g. "Division by Invariant Integers Using
+  // Multiplication" by Granlund and Montgomery (1994). magic_number (m) is set
+  // to ceil(2^k/d) for large enough k.
+  // The idea for item 2 originates from Schubfach.
+  constexpr auto info = div_small_pow10_infos[N - 1];
+  FMT_ASSERT(n <= info.divisor * 10, "n is too large");
+  constexpr uint32_t magic_number =
+      (1u << info.shift_amount) / info.divisor + 1;
+  n *= magic_number;
+  const uint32_t comparison_mask = (1u << info.shift_amount) - 1;
+  bool result = (n & comparison_mask) < magic_number;
   n >>= info.shift_amount;
   return result;
 }
 
 // Computes floor(n / pow(10, N)) for small n and N.
 // Precondition: n <= pow(10, N + 1).
-template <int N> uint32_t small_division_by_pow10(uint32_t n) FMT_NOEXCEPT {
-  static constexpr struct {
-    uint32_t magic_number;
-    int shift_amount;
-    uint32_t divisor_times_10;
-  } infos[] = {{0xcccd, 19, 100}, {0xa3d8, 22, 1000}};
-  constexpr auto info = infos[N - 1];
-  FMT_ASSERT(n <= info.divisor_times_10, "n is too large");
-  return n * info.magic_number >> info.shift_amount;
+template <int N> uint32_t small_division_by_pow10(uint32_t n) noexcept {
+  constexpr auto info = div_small_pow10_infos[N - 1];
+  FMT_ASSERT(n <= info.divisor * 10, "n is too large");
+  constexpr uint32_t magic_number =
+      (1u << info.shift_amount) / info.divisor + 1;
+  return (n * magic_number) >> info.shift_amount;
 }
 
 // Computes floor(n / 10^(kappa + 1)) (float)
-inline uint32_t divide_by_10_to_kappa_plus_1(uint32_t n) FMT_NOEXCEPT {
-  return n / float_info<float>::big_divisor;
+inline uint32_t divide_by_10_to_kappa_plus_1(uint32_t n) noexcept {
+  // 1374389535 = ceil(2^37/100)
+  return static_cast<uint32_t>((static_cast<uint64_t>(n) * 1374389535) >> 37);
 }
 // Computes floor(n / 10^(kappa + 1)) (double)
-inline uint64_t divide_by_10_to_kappa_plus_1(uint64_t n) FMT_NOEXCEPT {
-  return umul128_upper64(n, 0x83126e978d4fdf3c) >> 9;
+inline uint64_t divide_by_10_to_kappa_plus_1(uint64_t n) noexcept {
+  // 2361183241434822607 = ceil(2^(64+7)/1000)
+  return umul128_upper64(n, 2361183241434822607ull) >> 7;
 }
 
 // Various subroutines using pow10 cache
-template <class T> struct cache_accessor;
+template <typename T> struct cache_accessor;
 
 template <> struct cache_accessor<float> {
   using carrier_uint = float_info<float>::carrier_uint;
   using cache_entry_type = uint64_t;
 
-  static uint64_t get_cached_power(int k) FMT_NOEXCEPT {
+  static uint64_t get_cached_power(int k) noexcept {
     FMT_ASSERT(k >= float_info<float>::min_k && k <= float_info<float>::max_k,
                "k is out of range");
     static constexpr const uint64_t pow10_significands[] = {
@@ -1071,54 +278,65 @@ template <> struct cache_accessor<float> {
         0xb1a2bc2ec5000000, 0xde0b6b3a76400000, 0x8ac7230489e80000,
         0xad78ebc5ac620000, 0xd8d726b7177a8000, 0x878678326eac9000,
         0xa968163f0a57b400, 0xd3c21bcecceda100, 0x84595161401484a0,
-        0xa56fa5b99019a5c8, 0xcecb8f27f4200f3a, 0x813f3978f8940984,
-        0xa18f07d736b90be5, 0xc9f2c9cd04674ede, 0xfc6f7c4045812296,
-        0x9dc5ada82b70b59d, 0xc5371912364ce305, 0xf684df56c3e01bc6,
-        0x9a130b963a6c115c, 0xc097ce7bc90715b3, 0xf0bdc21abb48db20,
-        0x96769950b50d88f4, 0xbc143fa4e250eb31, 0xeb194f8e1ae525fd,
-        0x92efd1b8d0cf37be, 0xb7abc627050305ad, 0xe596b7b0c643c719,
-        0x8f7e32ce7bea5c6f, 0xb35dbf821ae4f38b, 0xe0352f62a19e306e};
+        0xa56fa5b99019a5c8, 0xcecb8f27f4200f3a, 0x813f3978f8940985,
+        0xa18f07d736b90be6, 0xc9f2c9cd04674edf, 0xfc6f7c4045812297,
+        0x9dc5ada82b70b59e, 0xc5371912364ce306, 0xf684df56c3e01bc7,
+        0x9a130b963a6c115d, 0xc097ce7bc90715b4, 0xf0bdc21abb48db21,
+        0x96769950b50d88f5, 0xbc143fa4e250eb32, 0xeb194f8e1ae525fe,
+        0x92efd1b8d0cf37bf, 0xb7abc627050305ae, 0xe596b7b0c643c71a,
+        0x8f7e32ce7bea5c70, 0xb35dbf821ae4f38c, 0xe0352f62a19e306f};
     return pow10_significands[k - float_info<float>::min_k];
   }
 
-  static carrier_uint compute_mul(carrier_uint u,
-                                  const cache_entry_type& cache) FMT_NOEXCEPT {
-    return umul96_upper32(u, cache);
+  struct compute_mul_result {
+    carrier_uint result;
+    bool is_integer;
+  };
+  struct compute_mul_parity_result {
+    bool parity;
+    bool is_integer;
+  };
+
+  static compute_mul_result compute_mul(
+      carrier_uint u, const cache_entry_type& cache) noexcept {
+    auto r = umul96_upper64(u, cache);
+    return {static_cast<carrier_uint>(r >> 32),
+            static_cast<carrier_uint>(r) == 0};
   }
 
   static uint32_t compute_delta(const cache_entry_type& cache,
-                                int beta_minus_1) FMT_NOEXCEPT {
-    return static_cast<uint32_t>(cache >> (64 - 1 - beta_minus_1));
+                                int beta) noexcept {
+    return static_cast<uint32_t>(cache >> (64 - 1 - beta));
   }
 
-  static bool compute_mul_parity(carrier_uint two_f,
-                                 const cache_entry_type& cache,
-                                 int beta_minus_1) FMT_NOEXCEPT {
-    FMT_ASSERT(beta_minus_1 >= 1, "");
-    FMT_ASSERT(beta_minus_1 < 64, "");
+  static compute_mul_parity_result compute_mul_parity(
+      carrier_uint two_f, const cache_entry_type& cache, int beta) noexcept {
+    FMT_ASSERT(beta >= 1, "");
+    FMT_ASSERT(beta < 64, "");
 
-    return ((umul96_lower64(two_f, cache) >> (64 - beta_minus_1)) & 1) != 0;
+    auto r = umul96_lower64(two_f, cache);
+    return {((r >> (64 - beta)) & 1) != 0,
+            static_cast<uint32_t>(r >> (32 - beta)) == 0};
   }
 
   static carrier_uint compute_left_endpoint_for_shorter_interval_case(
-      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+      const cache_entry_type& cache, int beta) noexcept {
     return static_cast<carrier_uint>(
-        (cache - (cache >> (float_info<float>::significand_bits + 2))) >>
-        (64 - float_info<float>::significand_bits - 1 - beta_minus_1));
+        (cache - (cache >> (num_significand_bits<float>() + 2))) >>
+        (64 - num_significand_bits<float>() - 1 - beta));
   }
 
   static carrier_uint compute_right_endpoint_for_shorter_interval_case(
-      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+      const cache_entry_type& cache, int beta) noexcept {
     return static_cast<carrier_uint>(
-        (cache + (cache >> (float_info<float>::significand_bits + 1))) >>
-        (64 - float_info<float>::significand_bits - 1 - beta_minus_1));
+        (cache + (cache >> (num_significand_bits<float>() + 1))) >>
+        (64 - num_significand_bits<float>() - 1 - beta));
   }
 
   static carrier_uint compute_round_up_for_shorter_interval_case(
-      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+      const cache_entry_type& cache, int beta) noexcept {
     return (static_cast<carrier_uint>(
-                cache >>
-                (64 - float_info<float>::significand_bits - 2 - beta_minus_1)) +
+                cache >> (64 - num_significand_bits<float>() - 2 - beta)) +
             1) /
            2;
   }
@@ -1126,13 +344,13 @@ template <> struct cache_accessor<float> {
 
 template <> struct cache_accessor<double> {
   using carrier_uint = float_info<double>::carrier_uint;
-  using cache_entry_type = uint128_wrapper;
+  using cache_entry_type = uint128_fallback;
 
-  static uint128_wrapper get_cached_power(int k) FMT_NOEXCEPT {
+  static uint128_fallback get_cached_power(int k) noexcept {
     FMT_ASSERT(k >= float_info<double>::min_k && k <= float_info<double>::max_k,
                "k is out of range");
 
-    static constexpr const uint128_wrapper pow10_significands[] = {
+    static constexpr const uint128_fallback pow10_significands[] = {
 #if FMT_USE_FULL_CACHE_DRAGONBOX
       {0xff77b1fcbebcdc4f, 0x25e8e89c13bb0f7b},
       {0x9faacf3df73609b1, 0x77b191618c54e9ad},
@@ -1482,278 +700,293 @@ template <> struct cache_accessor<double> {
       {0x85a36366eb71f041, 0x47a6da2b7f864750},
       {0xa70c3c40a64e6c51, 0x999090b65f67d924},
       {0xd0cf4b50cfe20765, 0xfff4b4e3f741cf6d},
-      {0x82818f1281ed449f, 0xbff8f10e7a8921a4},
-      {0xa321f2d7226895c7, 0xaff72d52192b6a0d},
-      {0xcbea6f8ceb02bb39, 0x9bf4f8a69f764490},
-      {0xfee50b7025c36a08, 0x02f236d04753d5b4},
-      {0x9f4f2726179a2245, 0x01d762422c946590},
-      {0xc722f0ef9d80aad6, 0x424d3ad2b7b97ef5},
-      {0xf8ebad2b84e0d58b, 0xd2e0898765a7deb2},
-      {0x9b934c3b330c8577, 0x63cc55f49f88eb2f},
-      {0xc2781f49ffcfa6d5, 0x3cbf6b71c76b25fb},
-      {0xf316271c7fc3908a, 0x8bef464e3945ef7a},
-      {0x97edd871cfda3a56, 0x97758bf0e3cbb5ac},
-      {0xbde94e8e43d0c8ec, 0x3d52eeed1cbea317},
-      {0xed63a231d4c4fb27, 0x4ca7aaa863ee4bdd},
-      {0x945e455f24fb1cf8, 0x8fe8caa93e74ef6a},
-      {0xb975d6b6ee39e436, 0xb3e2fd538e122b44},
-      {0xe7d34c64a9c85d44, 0x60dbbca87196b616},
-      {0x90e40fbeea1d3a4a, 0xbc8955e946fe31cd},
-      {0xb51d13aea4a488dd, 0x6babab6398bdbe41},
-      {0xe264589a4dcdab14, 0xc696963c7eed2dd1},
-      {0x8d7eb76070a08aec, 0xfc1e1de5cf543ca2},
-      {0xb0de65388cc8ada8, 0x3b25a55f43294bcb},
-      {0xdd15fe86affad912, 0x49ef0eb713f39ebe},
-      {0x8a2dbf142dfcc7ab, 0x6e3569326c784337},
-      {0xacb92ed9397bf996, 0x49c2c37f07965404},
-      {0xd7e77a8f87daf7fb, 0xdc33745ec97be906},
-      {0x86f0ac99b4e8dafd, 0x69a028bb3ded71a3},
-      {0xa8acd7c0222311bc, 0xc40832ea0d68ce0c},
-      {0xd2d80db02aabd62b, 0xf50a3fa490c30190},
-      {0x83c7088e1aab65db, 0x792667c6da79e0fa},
-      {0xa4b8cab1a1563f52, 0x577001b891185938},
-      {0xcde6fd5e09abcf26, 0xed4c0226b55e6f86},
-      {0x80b05e5ac60b6178, 0x544f8158315b05b4},
-      {0xa0dc75f1778e39d6, 0x696361ae3db1c721},
-      {0xc913936dd571c84c, 0x03bc3a19cd1e38e9},
-      {0xfb5878494ace3a5f, 0x04ab48a04065c723},
-      {0x9d174b2dcec0e47b, 0x62eb0d64283f9c76},
-      {0xc45d1df942711d9a, 0x3ba5d0bd324f8394},
-      {0xf5746577930d6500, 0xca8f44ec7ee36479},
-      {0x9968bf6abbe85f20, 0x7e998b13cf4e1ecb},
-      {0xbfc2ef456ae276e8, 0x9e3fedd8c321a67e},
-      {0xefb3ab16c59b14a2, 0xc5cfe94ef3ea101e},
-      {0x95d04aee3b80ece5, 0xbba1f1d158724a12},
-      {0xbb445da9ca61281f, 0x2a8a6e45ae8edc97},
-      {0xea1575143cf97226, 0xf52d09d71a3293bd},
-      {0x924d692ca61be758, 0x593c2626705f9c56},
-      {0xb6e0c377cfa2e12e, 0x6f8b2fb00c77836c},
-      {0xe498f455c38b997a, 0x0b6dfb9c0f956447},
-      {0x8edf98b59a373fec, 0x4724bd4189bd5eac},
-      {0xb2977ee300c50fe7, 0x58edec91ec2cb657},
-      {0xdf3d5e9bc0f653e1, 0x2f2967b66737e3ed},
-      {0x8b865b215899f46c, 0xbd79e0d20082ee74},
-      {0xae67f1e9aec07187, 0xecd8590680a3aa11},
-      {0xda01ee641a708de9, 0xe80e6f4820cc9495},
-      {0x884134fe908658b2, 0x3109058d147fdcdd},
-      {0xaa51823e34a7eede, 0xbd4b46f0599fd415},
-      {0xd4e5e2cdc1d1ea96, 0x6c9e18ac7007c91a},
-      {0x850fadc09923329e, 0x03e2cf6bc604ddb0},
-      {0xa6539930bf6bff45, 0x84db8346b786151c},
-      {0xcfe87f7cef46ff16, 0xe612641865679a63},
-      {0x81f14fae158c5f6e, 0x4fcb7e8f3f60c07e},
-      {0xa26da3999aef7749, 0xe3be5e330f38f09d},
-      {0xcb090c8001ab551c, 0x5cadf5bfd3072cc5},
-      {0xfdcb4fa002162a63, 0x73d9732fc7c8f7f6},
-      {0x9e9f11c4014dda7e, 0x2867e7fddcdd9afa},
-      {0xc646d63501a1511d, 0xb281e1fd541501b8},
-      {0xf7d88bc24209a565, 0x1f225a7ca91a4226},
-      {0x9ae757596946075f, 0x3375788de9b06958},
-      {0xc1a12d2fc3978937, 0x0052d6b1641c83ae},
-      {0xf209787bb47d6b84, 0xc0678c5dbd23a49a},
-      {0x9745eb4d50ce6332, 0xf840b7ba963646e0},
-      {0xbd176620a501fbff, 0xb650e5a93bc3d898},
-      {0xec5d3fa8ce427aff, 0xa3e51f138ab4cebe},
-      {0x93ba47c980e98cdf, 0xc66f336c36b10137},
-      {0xb8a8d9bbe123f017, 0xb80b0047445d4184},
-      {0xe6d3102ad96cec1d, 0xa60dc059157491e5},
-      {0x9043ea1ac7e41392, 0x87c89837ad68db2f},
-      {0xb454e4a179dd1877, 0x29babe4598c311fb},
-      {0xe16a1dc9d8545e94, 0xf4296dd6fef3d67a},
-      {0x8ce2529e2734bb1d, 0x1899e4a65f58660c},
-      {0xb01ae745b101e9e4, 0x5ec05dcff72e7f8f},
-      {0xdc21a1171d42645d, 0x76707543f4fa1f73},
-      {0x899504ae72497eba, 0x6a06494a791c53a8},
-      {0xabfa45da0edbde69, 0x0487db9d17636892},
-      {0xd6f8d7509292d603, 0x45a9d2845d3c42b6},
-      {0x865b86925b9bc5c2, 0x0b8a2392ba45a9b2},
-      {0xa7f26836f282b732, 0x8e6cac7768d7141e},
-      {0xd1ef0244af2364ff, 0x3207d795430cd926},
-      {0x8335616aed761f1f, 0x7f44e6bd49e807b8},
-      {0xa402b9c5a8d3a6e7, 0x5f16206c9c6209a6},
-      {0xcd036837130890a1, 0x36dba887c37a8c0f},
-      {0x802221226be55a64, 0xc2494954da2c9789},
-      {0xa02aa96b06deb0fd, 0xf2db9baa10b7bd6c},
-      {0xc83553c5c8965d3d, 0x6f92829494e5acc7},
-      {0xfa42a8b73abbf48c, 0xcb772339ba1f17f9},
-      {0x9c69a97284b578d7, 0xff2a760414536efb},
-      {0xc38413cf25e2d70d, 0xfef5138519684aba},
-      {0xf46518c2ef5b8cd1, 0x7eb258665fc25d69},
-      {0x98bf2f79d5993802, 0xef2f773ffbd97a61},
-      {0xbeeefb584aff8603, 0xaafb550ffacfd8fa},
-      {0xeeaaba2e5dbf6784, 0x95ba2a53f983cf38},
-      {0x952ab45cfa97a0b2, 0xdd945a747bf26183},
-      {0xba756174393d88df, 0x94f971119aeef9e4},
-      {0xe912b9d1478ceb17, 0x7a37cd5601aab85d},
-      {0x91abb422ccb812ee, 0xac62e055c10ab33a},
-      {0xb616a12b7fe617aa, 0x577b986b314d6009},
-      {0xe39c49765fdf9d94, 0xed5a7e85fda0b80b},
-      {0x8e41ade9fbebc27d, 0x14588f13be847307},
-      {0xb1d219647ae6b31c, 0x596eb2d8ae258fc8},
-      {0xde469fbd99a05fe3, 0x6fca5f8ed9aef3bb},
-      {0x8aec23d680043bee, 0x25de7bb9480d5854},
-      {0xada72ccc20054ae9, 0xaf561aa79a10ae6a},
-      {0xd910f7ff28069da4, 0x1b2ba1518094da04},
-      {0x87aa9aff79042286, 0x90fb44d2f05d0842},
-      {0xa99541bf57452b28, 0x353a1607ac744a53},
-      {0xd3fa922f2d1675f2, 0x42889b8997915ce8},
-      {0x847c9b5d7c2e09b7, 0x69956135febada11},
-      {0xa59bc234db398c25, 0x43fab9837e699095},
-      {0xcf02b2c21207ef2e, 0x94f967e45e03f4bb},
-      {0x8161afb94b44f57d, 0x1d1be0eebac278f5},
-      {0xa1ba1ba79e1632dc, 0x6462d92a69731732},
-      {0xca28a291859bbf93, 0x7d7b8f7503cfdcfe},
-      {0xfcb2cb35e702af78, 0x5cda735244c3d43e},
-      {0x9defbf01b061adab, 0x3a0888136afa64a7},
-      {0xc56baec21c7a1916, 0x088aaa1845b8fdd0},
-      {0xf6c69a72a3989f5b, 0x8aad549e57273d45},
-      {0x9a3c2087a63f6399, 0x36ac54e2f678864b},
-      {0xc0cb28a98fcf3c7f, 0x84576a1bb416a7dd},
-      {0xf0fdf2d3f3c30b9f, 0x656d44a2a11c51d5},
-      {0x969eb7c47859e743, 0x9f644ae5a4b1b325},
-      {0xbc4665b596706114, 0x873d5d9f0dde1fee},
-      {0xeb57ff22fc0c7959, 0xa90cb506d155a7ea},
-      {0x9316ff75dd87cbd8, 0x09a7f12442d588f2},
-      {0xb7dcbf5354e9bece, 0x0c11ed6d538aeb2f},
-      {0xe5d3ef282a242e81, 0x8f1668c8a86da5fa},
-      {0x8fa475791a569d10, 0xf96e017d694487bc},
-      {0xb38d92d760ec4455, 0x37c981dcc395a9ac},
-      {0xe070f78d3927556a, 0x85bbe253f47b1417},
-      {0x8c469ab843b89562, 0x93956d7478ccec8e},
-      {0xaf58416654a6babb, 0x387ac8d1970027b2},
-      {0xdb2e51bfe9d0696a, 0x06997b05fcc0319e},
-      {0x88fcf317f22241e2, 0x441fece3bdf81f03},
-      {0xab3c2fddeeaad25a, 0xd527e81cad7626c3},
-      {0xd60b3bd56a5586f1, 0x8a71e223d8d3b074},
-      {0x85c7056562757456, 0xf6872d5667844e49},
-      {0xa738c6bebb12d16c, 0xb428f8ac016561db},
-      {0xd106f86e69d785c7, 0xe13336d701beba52},
-      {0x82a45b450226b39c, 0xecc0024661173473},
-      {0xa34d721642b06084, 0x27f002d7f95d0190},
-      {0xcc20ce9bd35c78a5, 0x31ec038df7b441f4},
-      {0xff290242c83396ce, 0x7e67047175a15271},
-      {0x9f79a169bd203e41, 0x0f0062c6e984d386},
-      {0xc75809c42c684dd1, 0x52c07b78a3e60868},
-      {0xf92e0c3537826145, 0xa7709a56ccdf8a82},
-      {0x9bbcc7a142b17ccb, 0x88a66076400bb691},
-      {0xc2abf989935ddbfe, 0x6acff893d00ea435},
-      {0xf356f7ebf83552fe, 0x0583f6b8c4124d43},
-      {0x98165af37b2153de, 0xc3727a337a8b704a},
-      {0xbe1bf1b059e9a8d6, 0x744f18c0592e4c5c},
-      {0xeda2ee1c7064130c, 0x1162def06f79df73},
-      {0x9485d4d1c63e8be7, 0x8addcb5645ac2ba8},
-      {0xb9a74a0637ce2ee1, 0x6d953e2bd7173692},
-      {0xe8111c87c5c1ba99, 0xc8fa8db6ccdd0437},
-      {0x910ab1d4db9914a0, 0x1d9c9892400a22a2},
-      {0xb54d5e4a127f59c8, 0x2503beb6d00cab4b},
-      {0xe2a0b5dc971f303a, 0x2e44ae64840fd61d},
-      {0x8da471a9de737e24, 0x5ceaecfed289e5d2},
-      {0xb10d8e1456105dad, 0x7425a83e872c5f47},
-      {0xdd50f1996b947518, 0xd12f124e28f77719},
-      {0x8a5296ffe33cc92f, 0x82bd6b70d99aaa6f},
-      {0xace73cbfdc0bfb7b, 0x636cc64d1001550b},
-      {0xd8210befd30efa5a, 0x3c47f7e05401aa4e},
-      {0x8714a775e3e95c78, 0x65acfaec34810a71},
-      {0xa8d9d1535ce3b396, 0x7f1839a741a14d0d},
-      {0xd31045a8341ca07c, 0x1ede48111209a050},
-      {0x83ea2b892091e44d, 0x934aed0aab460432},
-      {0xa4e4b66b68b65d60, 0xf81da84d5617853f},
-      {0xce1de40642e3f4b9, 0x36251260ab9d668e},
-      {0x80d2ae83e9ce78f3, 0xc1d72b7c6b426019},
-      {0xa1075a24e4421730, 0xb24cf65b8612f81f},
-      {0xc94930ae1d529cfc, 0xdee033f26797b627},
-      {0xfb9b7cd9a4a7443c, 0x169840ef017da3b1},
-      {0x9d412e0806e88aa5, 0x8e1f289560ee864e},
-      {0xc491798a08a2ad4e, 0xf1a6f2bab92a27e2},
-      {0xf5b5d7ec8acb58a2, 0xae10af696774b1db},
-      {0x9991a6f3d6bf1765, 0xacca6da1e0a8ef29},
-      {0xbff610b0cc6edd3f, 0x17fd090a58d32af3},
-      {0xeff394dcff8a948e, 0xddfc4b4cef07f5b0},
-      {0x95f83d0a1fb69cd9, 0x4abdaf101564f98e},
-      {0xbb764c4ca7a4440f, 0x9d6d1ad41abe37f1},
-      {0xea53df5fd18d5513, 0x84c86189216dc5ed},
-      {0x92746b9be2f8552c, 0x32fd3cf5b4e49bb4},
-      {0xb7118682dbb66a77, 0x3fbc8c33221dc2a1},
-      {0xe4d5e82392a40515, 0x0fabaf3feaa5334a},
-      {0x8f05b1163ba6832d, 0x29cb4d87f2a7400e},
-      {0xb2c71d5bca9023f8, 0x743e20e9ef511012},
-      {0xdf78e4b2bd342cf6, 0x914da9246b255416},
-      {0x8bab8eefb6409c1a, 0x1ad089b6c2f7548e},
-      {0xae9672aba3d0c320, 0xa184ac2473b529b1},
-      {0xda3c0f568cc4f3e8, 0xc9e5d72d90a2741e},
-      {0x8865899617fb1871, 0x7e2fa67c7a658892},
-      {0xaa7eebfb9df9de8d, 0xddbb901b98feeab7},
-      {0xd51ea6fa85785631, 0x552a74227f3ea565},
-      {0x8533285c936b35de, 0xd53a88958f87275f},
-      {0xa67ff273b8460356, 0x8a892abaf368f137},
-      {0xd01fef10a657842c, 0x2d2b7569b0432d85},
-      {0x8213f56a67f6b29b, 0x9c3b29620e29fc73},
-      {0xa298f2c501f45f42, 0x8349f3ba91b47b8f},
-      {0xcb3f2f7642717713, 0x241c70a936219a73},
-      {0xfe0efb53d30dd4d7, 0xed238cd383aa0110},
-      {0x9ec95d1463e8a506, 0xf4363804324a40aa},
-      {0xc67bb4597ce2ce48, 0xb143c6053edcd0d5},
-      {0xf81aa16fdc1b81da, 0xdd94b7868e94050a},
-      {0x9b10a4e5e9913128, 0xca7cf2b4191c8326},
-      {0xc1d4ce1f63f57d72, 0xfd1c2f611f63a3f0},
-      {0xf24a01a73cf2dccf, 0xbc633b39673c8cec},
-      {0x976e41088617ca01, 0xd5be0503e085d813},
-      {0xbd49d14aa79dbc82, 0x4b2d8644d8a74e18},
-      {0xec9c459d51852ba2, 0xddf8e7d60ed1219e},
-      {0x93e1ab8252f33b45, 0xcabb90e5c942b503},
-      {0xb8da1662e7b00a17, 0x3d6a751f3b936243},
-      {0xe7109bfba19c0c9d, 0x0cc512670a783ad4},
-      {0x906a617d450187e2, 0x27fb2b80668b24c5},
-      {0xb484f9dc9641e9da, 0xb1f9f660802dedf6},
-      {0xe1a63853bbd26451, 0x5e7873f8a0396973},
-      {0x8d07e33455637eb2, 0xdb0b487b6423e1e8},
-      {0xb049dc016abc5e5f, 0x91ce1a9a3d2cda62},
-      {0xdc5c5301c56b75f7, 0x7641a140cc7810fb},
-      {0x89b9b3e11b6329ba, 0xa9e904c87fcb0a9d},
-      {0xac2820d9623bf429, 0x546345fa9fbdcd44},
-      {0xd732290fbacaf133, 0xa97c177947ad4095},
-      {0x867f59a9d4bed6c0, 0x49ed8eabcccc485d},
-      {0xa81f301449ee8c70, 0x5c68f256bfff5a74},
-      {0xd226fc195c6a2f8c, 0x73832eec6fff3111},
-      {0x83585d8fd9c25db7, 0xc831fd53c5ff7eab},
-      {0xa42e74f3d032f525, 0xba3e7ca8b77f5e55},
-      {0xcd3a1230c43fb26f, 0x28ce1bd2e55f35eb},
-      {0x80444b5e7aa7cf85, 0x7980d163cf5b81b3},
-      {0xa0555e361951c366, 0xd7e105bcc332621f},
-      {0xc86ab5c39fa63440, 0x8dd9472bf3fefaa7},
-      {0xfa856334878fc150, 0xb14f98f6f0feb951},
-      {0x9c935e00d4b9d8d2, 0x6ed1bf9a569f33d3},
-      {0xc3b8358109e84f07, 0x0a862f80ec4700c8},
-      {0xf4a642e14c6262c8, 0xcd27bb612758c0fa},
-      {0x98e7e9cccfbd7dbd, 0x8038d51cb897789c},
-      {0xbf21e44003acdd2c, 0xe0470a63e6bd56c3},
-      {0xeeea5d5004981478, 0x1858ccfce06cac74},
-      {0x95527a5202df0ccb, 0x0f37801e0c43ebc8},
-      {0xbaa718e68396cffd, 0xd30560258f54e6ba},
-      {0xe950df20247c83fd, 0x47c6b82ef32a2069},
-      {0x91d28b7416cdd27e, 0x4cdc331d57fa5441},
-      {0xb6472e511c81471d, 0xe0133fe4adf8e952},
-      {0xe3d8f9e563a198e5, 0x58180fddd97723a6},
-      {0x8e679c2f5e44ff8f, 0x570f09eaa7ea7648},
-      {0xb201833b35d63f73, 0x2cd2cc6551e513da},
-      {0xde81e40a034bcf4f, 0xf8077f7ea65e58d1},
-      {0x8b112e86420f6191, 0xfb04afaf27faf782},
-      {0xadd57a27d29339f6, 0x79c5db9af1f9b563},
-      {0xd94ad8b1c7380874, 0x18375281ae7822bc},
-      {0x87cec76f1c830548, 0x8f2293910d0b15b5},
-      {0xa9c2794ae3a3c69a, 0xb2eb3875504ddb22},
-      {0xd433179d9c8cb841, 0x5fa60692a46151eb},
-      {0x849feec281d7f328, 0xdbc7c41ba6bcd333},
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+      {0x849feec281d7f328, 0xdbc7c41ba6bcd334},
+      {0xa5c7ea73224deff3, 0x12b9b522906c0801},
+      {0xcf39e50feae16bef, 0xd768226b34870a01},
+      {0x81842f29f2cce375, 0xe6a1158300d46641},
+      {0xa1e53af46f801c53, 0x60495ae3c1097fd1},
+      {0xca5e89b18b602368, 0x385bb19cb14bdfc5},
+      {0xfcf62c1dee382c42, 0x46729e03dd9ed7b6},
+      {0x9e19db92b4e31ba9, 0x6c07a2c26a8346d2},
+      {0xc5a05277621be293, 0xc7098b7305241886},
+      {0xf70867153aa2db38, 0xb8cbee4fc66d1ea8},
+      {0x9a65406d44a5c903, 0x737f74f1dc043329},
+      {0xc0fe908895cf3b44, 0x505f522e53053ff3},
+      {0xf13e34aabb430a15, 0x647726b9e7c68ff0},
+      {0x96c6e0eab509e64d, 0x5eca783430dc19f6},
+      {0xbc789925624c5fe0, 0xb67d16413d132073},
+      {0xeb96bf6ebadf77d8, 0xe41c5bd18c57e890},
+      {0x933e37a534cbaae7, 0x8e91b962f7b6f15a},
+      {0xb80dc58e81fe95a1, 0x723627bbb5a4adb1},
+      {0xe61136f2227e3b09, 0xcec3b1aaa30dd91d},
+      {0x8fcac257558ee4e6, 0x213a4f0aa5e8a7b2},
+      {0xb3bd72ed2af29e1f, 0xa988e2cd4f62d19e},
+      {0xe0accfa875af45a7, 0x93eb1b80a33b8606},
+      {0x8c6c01c9498d8b88, 0xbc72f130660533c4},
+      {0xaf87023b9bf0ee6a, 0xeb8fad7c7f8680b5},
+      { 0xdb68c2ca82ed2a05,
+        0xa67398db9f6820e2 }
 #else
       {0xff77b1fcbebcdc4f, 0x25e8e89c13bb0f7b},
       {0xce5d73ff402d98e3, 0xfb0a3d212dc81290},
@@ -1768,17 +1001,17 @@ template <> struct cache_accessor<double> {
       {0xf1c90080baf72cb1, 0x5324c68b12dd6339},
       {0xc350000000000000, 0x0000000000000000},
       {0x9dc5ada82b70b59d, 0xf020000000000000},
-      {0xfee50b7025c36a08, 0x02f236d04753d5b4},
-      {0xcde6fd5e09abcf26, 0xed4c0226b55e6f86},
-      {0xa6539930bf6bff45, 0x84db8346b786151c},
-      {0x865b86925b9bc5c2, 0x0b8a2392ba45a9b2},
-      {0xd910f7ff28069da4, 0x1b2ba1518094da04},
-      {0xaf58416654a6babb, 0x387ac8d1970027b2},
-      {0x8da471a9de737e24, 0x5ceaecfed289e5d2},
-      {0xe4d5e82392a40515, 0x0fabaf3feaa5334a},
-      {0xb8da1662e7b00a17, 0x3d6a751f3b936243},
-      { 0x95527a5202df0ccb,
-        0x0f37801e0c43ebc8 }
+      {0xfee50b7025c36a08, 0x02f236d04753d5b5},
+      {0xcde6fd5e09abcf26, 0xed4c0226b55e6f87},
+      {0xa6539930bf6bff45, 0x84db8346b786151d},
+      {0x865b86925b9bc5c2, 0x0b8a2392ba45a9b3},
+      {0xd910f7ff28069da4, 0x1b2ba1518094da05},
+      {0xaf58416654a6babb, 0x387ac8d1970027b3},
+      {0x8da471a9de737e24, 0x5ceaecfed289e5d3},
+      {0xe4d5e82392a40515, 0x0fabaf3feaa5334b},
+      {0xb8da1662e7b00a17, 0x3d6a751f3b936244},
+      {0x95527a5202df0ccb, 0x0f37801e0c43ebc9},
+      {0xf13e34aabb430a15, 0x647726b9e7c68ff0}
 #endif
     };
 
@@ -1796,15 +1029,6 @@ template <> struct cache_accessor<double> {
         0x0001b1ae4d6e2ef5, 0x000878678326eac9, 0x002a5a058fc295ed,
         0x00d3c21bcecceda1, 0x0422ca8b0a00a425, 0x14adf4b7320334b9};
 
-    static constexpr const uint32_t pow10_recovery_errors[] = {
-        0x50001400, 0x54044100, 0x54014555, 0x55954415, 0x54115555, 0x00000001,
-        0x50000000, 0x00104000, 0x54010004, 0x05004001, 0x55555544, 0x41545555,
-        0x54040551, 0x15445545, 0x51555514, 0x10000015, 0x00101100, 0x01100015,
-        0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x04450514, 0x45414110,
-        0x55555145, 0x50544050, 0x15040155, 0x11054140, 0x50111514, 0x11451454,
-        0x00400541, 0x00000000, 0x55555450, 0x10056551, 0x10054011, 0x55551014,
-        0x69514555, 0x05151109, 0x00155555};
-
     static const int compression_ratio = 27;
 
     // Compute base index.
@@ -1813,7 +1037,7 @@ template <> struct cache_accessor<double> {
     int offset = k - kb;
 
     // Get base cache.
-    uint128_wrapper base_cache = pow10_significands[cache_index];
+    uint128_fallback base_cache = pow10_significands[cache_index];
     if (offset == 0) return base_cache;
 
     // Compute the required amount of bit-shift.
@@ -1822,9 +1046,8 @@ template <> struct cache_accessor<double> {
 
     // Try to recover the real cache.
     uint64_t pow5 = powers_of_5_64[offset];
-    uint128_wrapper recovered_cache = umul128(base_cache.high(), pow5);
-    uint128_wrapper middle_low =
-        umul128(base_cache.low() - (kb < 0 ? 1u : 0u), pow5);
+    uint128_fallback recovered_cache = umul128(base_cache.high(), pow5);
+    uint128_fallback middle_low = umul128(base_cache.low(), pow5);
 
     recovered_cache += middle_low.high();
 
@@ -1832,227 +1055,172 @@ template <> struct cache_accessor<double> {
     uint64_t middle_to_low = recovered_cache.low() << (64 - alpha);
 
     recovered_cache =
-        uint128_wrapper{(recovered_cache.low() >> alpha) | high_to_middle,
-                        ((middle_low.low() >> alpha) | middle_to_low)};
-
-    if (kb < 0) recovered_cache += 1;
-
-    // Get error.
-    int error_idx = (k - float_info<double>::min_k) / 16;
-    uint32_t error = (pow10_recovery_errors[error_idx] >>
-                      ((k - float_info<double>::min_k) % 16) * 2) &
-                     0x3;
-
-    // Add the error back.
-    FMT_ASSERT(recovered_cache.low() + error >= recovered_cache.low(), "");
-    return {recovered_cache.high(), recovered_cache.low() + error};
+        uint128_fallback{(recovered_cache.low() >> alpha) | high_to_middle,
+                         ((middle_low.low() >> alpha) | middle_to_low)};
+    FMT_ASSERT(recovered_cache.low() + 1 != 0, "");
+    return {recovered_cache.high(), recovered_cache.low() + 1};
 #endif
   }
 
-  static carrier_uint compute_mul(carrier_uint u,
-                                  const cache_entry_type& cache) FMT_NOEXCEPT {
-    return umul192_upper64(u, cache);
+  struct compute_mul_result {
+    carrier_uint result;
+    bool is_integer;
+  };
+  struct compute_mul_parity_result {
+    bool parity;
+    bool is_integer;
+  };
+
+  static compute_mul_result compute_mul(
+      carrier_uint u, const cache_entry_type& cache) noexcept {
+    auto r = umul192_upper128(u, cache);
+    return {r.high(), r.low() == 0};
   }
 
   static uint32_t compute_delta(cache_entry_type const& cache,
-                                int beta_minus_1) FMT_NOEXCEPT {
-    return static_cast<uint32_t>(cache.high() >> (64 - 1 - beta_minus_1));
+                                int beta) noexcept {
+    return static_cast<uint32_t>(cache.high() >> (64 - 1 - beta));
   }
 
-  static bool compute_mul_parity(carrier_uint two_f,
-                                 const cache_entry_type& cache,
-                                 int beta_minus_1) FMT_NOEXCEPT {
-    FMT_ASSERT(beta_minus_1 >= 1, "");
-    FMT_ASSERT(beta_minus_1 < 64, "");
+  static compute_mul_parity_result compute_mul_parity(
+      carrier_uint two_f, const cache_entry_type& cache, int beta) noexcept {
+    FMT_ASSERT(beta >= 1, "");
+    FMT_ASSERT(beta < 64, "");
 
-    return ((umul192_middle64(two_f, cache) >> (64 - beta_minus_1)) & 1) != 0;
+    auto r = umul192_lower128(two_f, cache);
+    return {((r.high() >> (64 - beta)) & 1) != 0,
+            ((r.high() << beta) | (r.low() >> (64 - beta))) == 0};
   }
 
   static carrier_uint compute_left_endpoint_for_shorter_interval_case(
-      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+      const cache_entry_type& cache, int beta) noexcept {
     return (cache.high() -
-            (cache.high() >> (float_info<double>::significand_bits + 2))) >>
-           (64 - float_info<double>::significand_bits - 1 - beta_minus_1);
+            (cache.high() >> (num_significand_bits<double>() + 2))) >>
+           (64 - num_significand_bits<double>() - 1 - beta);
   }
 
   static carrier_uint compute_right_endpoint_for_shorter_interval_case(
-      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
+      const cache_entry_type& cache, int beta) noexcept {
     return (cache.high() +
-            (cache.high() >> (float_info<double>::significand_bits + 1))) >>
-           (64 - float_info<double>::significand_bits - 1 - beta_minus_1);
+            (cache.high() >> (num_significand_bits<double>() + 1))) >>
+           (64 - num_significand_bits<double>() - 1 - beta);
   }
 
   static carrier_uint compute_round_up_for_shorter_interval_case(
-      const cache_entry_type& cache, int beta_minus_1) FMT_NOEXCEPT {
-    return ((cache.high() >>
-             (64 - float_info<double>::significand_bits - 2 - beta_minus_1)) +
+      const cache_entry_type& cache, int beta) noexcept {
+    return ((cache.high() >> (64 - num_significand_bits<double>() - 2 - beta)) +
             1) /
            2;
   }
 };
 
-// Various integer checks
-template <class T>
-bool is_left_endpoint_integer_shorter_interval(int exponent) FMT_NOEXCEPT {
-  return exponent >=
-             float_info<
-                 T>::case_shorter_interval_left_endpoint_lower_threshold &&
-         exponent <=
-             float_info<T>::case_shorter_interval_left_endpoint_upper_threshold;
-}
-template <class T>
-bool is_endpoint_integer(typename float_info<T>::carrier_uint two_f,
-                         int exponent, int minus_k) FMT_NOEXCEPT {
-  if (exponent < float_info<T>::case_fc_pm_half_lower_threshold) return false;
-  // For k >= 0.
-  if (exponent <= float_info<T>::case_fc_pm_half_upper_threshold) return true;
-  // For k < 0.
-  if (exponent > float_info<T>::divisibility_check_by_5_threshold) return false;
-  return divisible_by_power_of_5(two_f, minus_k);
+FMT_FUNC uint128_fallback get_cached_power(int k) noexcept {
+  return cache_accessor<double>::get_cached_power(k);
 }
 
-template <class T>
-bool is_center_integer(typename float_info<T>::carrier_uint two_f, int exponent,
-                       int minus_k) FMT_NOEXCEPT {
-  // Exponent for 5 is negative.
-  if (exponent > float_info<T>::divisibility_check_by_5_threshold) return false;
-  if (exponent > float_info<T>::case_fc_upper_threshold)
-    return divisible_by_power_of_5(two_f, minus_k);
-  // Both exponents are nonnegative.
-  if (exponent >= float_info<T>::case_fc_lower_threshold) return true;
-  // Exponent for 2 is negative.
-  return divisible_by_power_of_2(two_f, minus_k - exponent + 1);
+// Various integer checks
+template <typename T>
+bool is_left_endpoint_integer_shorter_interval(int exponent) noexcept {
+  const int case_shorter_interval_left_endpoint_lower_threshold = 2;
+  const int case_shorter_interval_left_endpoint_upper_threshold = 3;
+  return exponent >= case_shorter_interval_left_endpoint_lower_threshold &&
+         exponent <= case_shorter_interval_left_endpoint_upper_threshold;
 }
 
 // Remove trailing zeros from n and return the number of zeros removed (float)
-FMT_INLINE int remove_trailing_zeros(uint32_t& n) FMT_NOEXCEPT {
-#ifdef FMT_BUILTIN_CTZ
-  int t = FMT_BUILTIN_CTZ(n);
-#else
-  int t = ctz(n);
-#endif
-  if (t > float_info<float>::max_trailing_zeros)
-    t = float_info<float>::max_trailing_zeros;
-
-  const uint32_t mod_inv1 = 0xcccccccd;
-  const uint32_t max_quotient1 = 0x33333333;
-  const uint32_t mod_inv2 = 0xc28f5c29;
-  const uint32_t max_quotient2 = 0x0a3d70a3;
+FMT_INLINE int remove_trailing_zeros(uint32_t& n) noexcept {
+  FMT_ASSERT(n != 0, "");
+  // Modular inverse of 5 (mod 2^32): (mod_inv_5 * 5) mod 2^32 = 1.
+  // See https://github.com/fmtlib/fmt/issues/3163 for more details.
+  const uint32_t mod_inv_5 = 0xcccccccd;
+  // Casts are needed to workaround a bug in MSVC 19.22 and older.
+  const uint32_t mod_inv_25 =
+      static_cast<uint32_t>(uint64_t(mod_inv_5) * mod_inv_5);
 
   int s = 0;
-  for (; s < t - 1; s += 2) {
-    if (n * mod_inv2 > max_quotient2) break;
-    n *= mod_inv2;
+  while (true) {
+    auto q = rotr(n * mod_inv_25, 2);
+    if (q > max_value<uint32_t>() / 100) break;
+    n = q;
+    s += 2;
   }
-  if (s < t && n * mod_inv1 <= max_quotient1) {
-    n *= mod_inv1;
-    ++s;
+  auto q = rotr(n * mod_inv_5, 1);
+  if (q <= max_value<uint32_t>() / 10) {
+    n = q;
+    s |= 1;
   }
-  n >>= s;
   return s;
 }
 
 // Removes trailing zeros and returns the number of zeros removed (double)
-FMT_INLINE int remove_trailing_zeros(uint64_t& n) FMT_NOEXCEPT {
-#ifdef FMT_BUILTIN_CTZLL
-  int t = FMT_BUILTIN_CTZLL(n);
-#else
-  int t = ctzll(n);
-#endif
-  if (t > float_info<double>::max_trailing_zeros)
-    t = float_info<double>::max_trailing_zeros;
-  // Divide by 10^8 and reduce to 32-bits
-  // Since ret_value.significand <= (2^64 - 1) / 1000 < 10^17,
-  // both of the quotient and the r should fit in 32-bits
-
-  const uint32_t mod_inv1 = 0xcccccccd;
-  const uint32_t max_quotient1 = 0x33333333;
-  const uint64_t mod_inv8 = 0xc767074b22e90e21;
-  const uint64_t max_quotient8 = 0x00002af31dc46118;
-
-  // If the number is divisible by 1'0000'0000, work with the quotient
-  if (t >= 8) {
-    auto quotient_candidate = n * mod_inv8;
-
-    if (quotient_candidate <= max_quotient8) {
-      auto quotient = static_cast<uint32_t>(quotient_candidate >> 8);
-
-      int s = 8;
-      for (; s < t; ++s) {
-        if (quotient * mod_inv1 > max_quotient1) break;
-        quotient *= mod_inv1;
-      }
-      quotient >>= (s - 8);
-      n = quotient;
-      return s;
+FMT_INLINE int remove_trailing_zeros(uint64_t& n) noexcept {
+  FMT_ASSERT(n != 0, "");
+
+  // This magic number is ceil(2^90 / 10^8).
+  constexpr uint64_t magic_number = 12379400392853802749ull;
+  auto nm = umul128(n, magic_number);
+
+  // Is n is divisible by 10^8?
+  if ((nm.high() & ((1ull << (90 - 64)) - 1)) == 0 && nm.low() < magic_number) {
+    // If yes, work with the quotient.
+    auto n32 = static_cast<uint32_t>(nm.high() >> (90 - 64));
+
+    const uint32_t mod_inv_5 = 0xcccccccd;
+    const uint32_t mod_inv_25 = mod_inv_5 * mod_inv_5;
+
+    int s = 8;
+    while (true) {
+      auto q = rotr(n32 * mod_inv_25, 2);
+      if (q > max_value<uint32_t>() / 100) break;
+      n32 = q;
+      s += 2;
+    }
+    auto q = rotr(n32 * mod_inv_5, 1);
+    if (q <= max_value<uint32_t>() / 10) {
+      n32 = q;
+      s |= 1;
     }
-  }
-
-  // Otherwise, work with the remainder
-  auto quotient = static_cast<uint32_t>(n / 100000000);
-  auto remainder = static_cast<uint32_t>(n - 100000000 * quotient);
-
-  if (t == 0 || remainder * mod_inv1 > max_quotient1) {
-    return 0;
-  }
-  remainder *= mod_inv1;
-
-  if (t == 1 || remainder * mod_inv1 > max_quotient1) {
-    n = (remainder >> 1) + quotient * 10000000ull;
-    return 1;
-  }
-  remainder *= mod_inv1;
-
-  if (t == 2 || remainder * mod_inv1 > max_quotient1) {
-    n = (remainder >> 2) + quotient * 1000000ull;
-    return 2;
-  }
-  remainder *= mod_inv1;
 
-  if (t == 3 || remainder * mod_inv1 > max_quotient1) {
-    n = (remainder >> 3) + quotient * 100000ull;
-    return 3;
+    n = n32;
+    return s;
   }
-  remainder *= mod_inv1;
 
-  if (t == 4 || remainder * mod_inv1 > max_quotient1) {
-    n = (remainder >> 4) + quotient * 10000ull;
-    return 4;
-  }
-  remainder *= mod_inv1;
+  // If n is not divisible by 10^8, work with n itself.
+  const uint64_t mod_inv_5 = 0xcccccccccccccccd;
+  const uint64_t mod_inv_25 = mod_inv_5 * mod_inv_5;
 
-  if (t == 5 || remainder * mod_inv1 > max_quotient1) {
-    n = (remainder >> 5) + quotient * 1000ull;
-    return 5;
+  int s = 0;
+  while (true) {
+    auto q = rotr(n * mod_inv_25, 2);
+    if (q > max_value<uint64_t>() / 100) break;
+    n = q;
+    s += 2;
   }
-  remainder *= mod_inv1;
-
-  if (t == 6 || remainder * mod_inv1 > max_quotient1) {
-    n = (remainder >> 6) + quotient * 100ull;
-    return 6;
+  auto q = rotr(n * mod_inv_5, 1);
+  if (q <= max_value<uint64_t>() / 10) {
+    n = q;
+    s |= 1;
   }
-  remainder *= mod_inv1;
 
-  n = (remainder >> 7) + quotient * 10ull;
-  return 7;
+  return s;
 }
 
 // The main algorithm for shorter interval case
-template <class T>
-FMT_INLINE decimal_fp<T> shorter_interval_case(int exponent) FMT_NOEXCEPT {
+template <typename T>
+FMT_INLINE decimal_fp<T> shorter_interval_case(int exponent) noexcept {
   decimal_fp<T> ret_value;
   // Compute k and beta
   const int minus_k = floor_log10_pow2_minus_log10_4_over_3(exponent);
-  const int beta_minus_1 = exponent + floor_log2_pow10(-minus_k);
+  const int beta = exponent + floor_log2_pow10(-minus_k);
 
   // Compute xi and zi
   using cache_entry_type = typename cache_accessor<T>::cache_entry_type;
   const cache_entry_type cache = cache_accessor<T>::get_cached_power(-minus_k);
 
   auto xi = cache_accessor<T>::compute_left_endpoint_for_shorter_interval_case(
-      cache, beta_minus_1);
+      cache, beta);
   auto zi = cache_accessor<T>::compute_right_endpoint_for_shorter_interval_case(
-      cache, beta_minus_1);
+      cache, beta);
 
   // If the left endpoint is not an integer, increase it
   if (!is_left_endpoint_integer_shorter_interval<T>(exponent)) ++xi;
@@ -2069,8 +1237,8 @@ FMT_INLINE decimal_fp<T> shorter_interval_case(int exponent) FMT_NOEXCEPT {
 
   // Otherwise, compute the round-up of y
   ret_value.significand =
-      cache_accessor<T>::compute_round_up_for_shorter_interval_case(
-          cache, beta_minus_1);
+      cache_accessor<T>::compute_round_up_for_shorter_interval_case(cache,
+                                                                    beta);
   ret_value.exponent = minus_k;
 
   // When tie occurs, choose one of them according to the rule
@@ -2085,7 +1253,7 @@ FMT_INLINE decimal_fp<T> shorter_interval_case(int exponent) FMT_NOEXCEPT {
   return ret_value;
 }
 
-template <typename T> decimal_fp<T> to_decimal(T x) FMT_NOEXCEPT {
+template <typename T> decimal_fp<T> to_decimal(T x) noexcept {
   // Step 1: integer promotion & Schubfach multiplier calculation.
 
   using carrier_uint = typename float_info<T>::carrier_uint;
@@ -2094,23 +1262,25 @@ template <typename T> decimal_fp<T> to_decimal(T x) FMT_NOEXCEPT {
 
   // Extract significand bits and exponent bits.
   const carrier_uint significand_mask =
-      (static_cast<carrier_uint>(1) << float_info<T>::significand_bits) - 1;
+      (static_cast<carrier_uint>(1) << num_significand_bits<T>()) - 1;
   carrier_uint significand = (br & significand_mask);
-  int exponent = static_cast<int>((br & exponent_mask<T>()) >>
-                                  float_info<T>::significand_bits);
+  int exponent =
+      static_cast<int>((br & exponent_mask<T>()) >> num_significand_bits<T>());
 
   if (exponent != 0) {  // Check if normal.
-    exponent += float_info<T>::exponent_bias - float_info<T>::significand_bits;
+    exponent -= exponent_bias<T>() + num_significand_bits<T>();
 
     // Shorter interval case; proceed like Schubfach.
+    // In fact, when exponent == 1 and significand == 0, the interval is
+    // regular. However, it can be shown that the end-results are anyway same.
     if (significand == 0) return shorter_interval_case<T>(exponent);
 
-    significand |=
-        (static_cast<carrier_uint>(1) << float_info<T>::significand_bits);
+    significand |= (static_cast<carrier_uint>(1) << num_significand_bits<T>());
   } else {
     // Subnormal case; the interval is always regular.
     if (significand == 0) return {0, 0};
-    exponent = float_info<T>::min_exponent - float_info<T>::significand_bits;
+    exponent =
+        std::numeric_limits<T>::min_exponent - num_significand_bits<T>() - 1;
   }
 
   const bool include_left_endpoint = (significand % 2 == 0);
@@ -2119,413 +1289,104 @@ template <typename T> decimal_fp<T> to_decimal(T x) FMT_NOEXCEPT {
   // Compute k and beta.
   const int minus_k = floor_log10_pow2(exponent) - float_info<T>::kappa;
   const cache_entry_type cache = cache_accessor<T>::get_cached_power(-minus_k);
-  const int beta_minus_1 = exponent + floor_log2_pow10(-minus_k);
+  const int beta = exponent + floor_log2_pow10(-minus_k);
 
-  // Compute zi and deltai
+  // Compute zi and deltai.
   // 10^kappa <= deltai < 10^(kappa + 1)
-  const uint32_t deltai = cache_accessor<T>::compute_delta(cache, beta_minus_1);
+  const uint32_t deltai = cache_accessor<T>::compute_delta(cache, beta);
   const carrier_uint two_fc = significand << 1;
-  const carrier_uint two_fr = two_fc | 1;
-  const carrier_uint zi =
-      cache_accessor<T>::compute_mul(two_fr << beta_minus_1, cache);
 
-  // Step 2: Try larger divisor; remove trailing zeros if necessary
+  // For the case of binary32, the result of integer check is not correct for
+  // 29711844 * 2^-82
+  // = 6.1442653300000000008655037797566933477355632930994033813476... * 10^-18
+  // and 29711844 * 2^-81
+  // = 1.2288530660000000001731007559513386695471126586198806762695... * 10^-17,
+  // and they are the unique counterexamples. However, since 29711844 is even,
+  // this does not cause any problem for the endpoints calculations; it can only
+  // cause a problem when we need to perform integer check for the center.
+  // Fortunately, with these inputs, that branch is never executed, so we are
+  // fine.
+  const typename cache_accessor<T>::compute_mul_result z_mul =
+      cache_accessor<T>::compute_mul((two_fc | 1) << beta, cache);
+
+  // Step 2: Try larger divisor; remove trailing zeros if necessary.
 
   // Using an upper bound on zi, we might be able to optimize the division
-  // better than the compiler; we are computing zi / big_divisor here
+  // better than the compiler; we are computing zi / big_divisor here.
   decimal_fp<T> ret_value;
-  ret_value.significand = divide_by_10_to_kappa_plus_1(zi);
-  uint32_t r = static_cast<uint32_t>(zi - float_info<T>::big_divisor *
-                                              ret_value.significand);
+  ret_value.significand = divide_by_10_to_kappa_plus_1(z_mul.result);
+  uint32_t r = static_cast<uint32_t>(z_mul.result - float_info<T>::big_divisor *
+                                                        ret_value.significand);
 
-  if (r > deltai) {
-    goto small_divisor_case_label;
-  } else if (r < deltai) {
-    // Exclude the right endpoint if necessary
-    if (r == 0 && !include_right_endpoint &&
-        is_endpoint_integer<T>(two_fr, exponent, minus_k)) {
+  if (r < deltai) {
+    // Exclude the right endpoint if necessary.
+    if (r == 0 && (z_mul.is_integer & !include_right_endpoint)) {
       --ret_value.significand;
       r = float_info<T>::big_divisor;
       goto small_divisor_case_label;
     }
+  } else if (r > deltai) {
+    goto small_divisor_case_label;
   } else {
-    // r == deltai; compare fractional parts
-    // Check conditions in the order different from the paper
-    // to take advantage of short-circuiting
-    const carrier_uint two_fl = two_fc - 1;
-    if ((!include_left_endpoint ||
-         !is_endpoint_integer<T>(two_fl, exponent, minus_k)) &&
-        !cache_accessor<T>::compute_mul_parity(two_fl, cache, beta_minus_1)) {
+    // r == deltai; compare fractional parts.
+    const typename cache_accessor<T>::compute_mul_parity_result x_mul =
+        cache_accessor<T>::compute_mul_parity(two_fc - 1, cache, beta);
+
+    if (!(x_mul.parity | (x_mul.is_integer & include_left_endpoint)))
       goto small_divisor_case_label;
-    }
   }
   ret_value.exponent = minus_k + float_info<T>::kappa + 1;
 
-  // We may need to remove trailing zeros
+  // We may need to remove trailing zeros.
   ret_value.exponent += remove_trailing_zeros(ret_value.significand);
   return ret_value;
 
-  // Step 3: Find the significand with the smaller divisor
+  // Step 3: Find the significand with the smaller divisor.
 
 small_divisor_case_label:
   ret_value.significand *= 10;
   ret_value.exponent = minus_k + float_info<T>::kappa;
 
-  const uint32_t mask = (1u << float_info<T>::kappa) - 1;
-  auto dist = r - (deltai / 2) + (float_info<T>::small_divisor / 2);
-
-  // Is dist divisible by 2^kappa?
-  if ((dist & mask) == 0) {
-    const bool approx_y_parity =
-        ((dist ^ (float_info<T>::small_divisor / 2)) & 1) != 0;
-    dist >>= float_info<T>::kappa;
-
-    // Is dist divisible by 5^kappa?
-    if (check_divisibility_and_divide_by_pow5<float_info<T>::kappa>(dist)) {
-      ret_value.significand += dist;
-
-      // Check z^(f) >= epsilon^(f)
-      // We have either yi == zi - epsiloni or yi == (zi - epsiloni) - 1,
-      // where yi == zi - epsiloni if and only if z^(f) >= epsilon^(f)
-      // Since there are only 2 possibilities, we only need to care about the
-      // parity. Also, zi and r should have the same parity since the divisor
-      // is an even number
-      if (cache_accessor<T>::compute_mul_parity(two_fc, cache, beta_minus_1) !=
-          approx_y_parity) {
-        --ret_value.significand;
-      } else {
-        // If z^(f) >= epsilon^(f), we might have a tie
-        // when z^(f) == epsilon^(f), or equivalently, when y is an integer
-        if (is_center_integer<T>(two_fc, exponent, minus_k)) {
-          ret_value.significand = ret_value.significand % 2 == 0
-                                      ? ret_value.significand
-                                      : ret_value.significand - 1;
-        }
-      }
-    }
-    // Is dist not divisible by 5^kappa?
-    else {
-      ret_value.significand += dist;
-    }
-  }
-  // Is dist not divisible by 2^kappa?
-  else {
-    // Since we know dist is small, we might be able to optimize the division
-    // better than the compiler; we are computing dist / small_divisor here
-    ret_value.significand +=
-        small_division_by_pow10<float_info<T>::kappa>(dist);
-  }
+  uint32_t dist = r - (deltai / 2) + (float_info<T>::small_divisor / 2);
+  const bool approx_y_parity =
+      ((dist ^ (float_info<T>::small_divisor / 2)) & 1) != 0;
+
+  // Is dist divisible by 10^kappa?
+  const bool divisible_by_small_divisor =
+      check_divisibility_and_divide_by_pow10<float_info<T>::kappa>(dist);
+
+  // Add dist / 10^kappa to the significand.
+  ret_value.significand += dist;
+
+  if (!divisible_by_small_divisor) return ret_value;
+
+  // Check z^(f) >= epsilon^(f).
+  // We have either yi == zi - epsiloni or yi == (zi - epsiloni) - 1,
+  // where yi == zi - epsiloni if and only if z^(f) >= epsilon^(f).
+  // Since there are only 2 possibilities, we only need to care about the
+  // parity. Also, zi and r should have the same parity since the divisor
+  // is an even number.
+  const auto y_mul = cache_accessor<T>::compute_mul_parity(two_fc, cache, beta);
+
+  // If z^(f) >= epsilon^(f), we might have a tie when z^(f) == epsilon^(f),
+  // or equivalently, when y is an integer.
+  if (y_mul.parity != approx_y_parity)
+    --ret_value.significand;
+  else if (y_mul.is_integer & (ret_value.significand % 2 != 0))
+    --ret_value.significand;
   return ret_value;
 }
 }  // namespace dragonbox
-
-// Formats a floating-point number using a variation of the Fixed-Precision
-// Positive Floating-Point Printout ((FPP)^2) algorithm by Steele & White:
-// https://fmt.dev/papers/p372-steele.pdf.
-FMT_CONSTEXPR20 inline void format_dragon(fp value, bool is_predecessor_closer,
-                                          int num_digits, buffer<char>& buf,
-                                          int& exp10) {
-  bigint numerator;    // 2 * R in (FPP)^2.
-  bigint denominator;  // 2 * S in (FPP)^2.
-  // lower and upper are differences between value and corresponding boundaries.
-  bigint lower;             // (M^- in (FPP)^2).
-  bigint upper_store;       // upper's value if different from lower.
-  bigint* upper = nullptr;  // (M^+ in (FPP)^2).
-  // Shift numerator and denominator by an extra bit or two (if lower boundary
-  // is closer) to make lower and upper integers. This eliminates multiplication
-  // by 2 during later computations.
-  int shift = is_predecessor_closer ? 2 : 1;
-  uint64_t significand = value.f << shift;
-  if (value.e >= 0) {
-    numerator.assign(significand);
-    numerator <<= value.e;
-    lower.assign(1);
-    lower <<= value.e;
-    if (shift != 1) {
-      upper_store.assign(1);
-      upper_store <<= value.e + 1;
-      upper = &upper_store;
-    }
-    denominator.assign_pow10(exp10);
-    denominator <<= shift;
-  } else if (exp10 < 0) {
-    numerator.assign_pow10(-exp10);
-    lower.assign(numerator);
-    if (shift != 1) {
-      upper_store.assign(numerator);
-      upper_store <<= 1;
-      upper = &upper_store;
-    }
-    numerator *= significand;
-    denominator.assign(1);
-    denominator <<= shift - value.e;
-  } else {
-    numerator.assign(significand);
-    denominator.assign_pow10(exp10);
-    denominator <<= shift - value.e;
-    lower.assign(1);
-    if (shift != 1) {
-      upper_store.assign(1ULL << 1);
-      upper = &upper_store;
-    }
-  }
-  // Invariant: value == (numerator / denominator) * pow(10, exp10).
-  if (num_digits < 0) {
-    // Generate the shortest representation.
-    if (!upper) upper = &lower;
-    bool even = (value.f & 1) == 0;
-    num_digits = 0;
-    char* data = buf.data();
-    for (;;) {
-      int digit = numerator.divmod_assign(denominator);
-      bool low = compare(numerator, lower) - even < 0;  // numerator <[=] lower.
-      // numerator + upper >[=] pow10:
-      bool high = add_compare(numerator, *upper, denominator) + even > 0;
-      data[num_digits++] = static_cast<char>('0' + digit);
-      if (low || high) {
-        if (!low) {
-          ++data[num_digits - 1];
-        } else if (high) {
-          int result = add_compare(numerator, numerator, denominator);
-          // Round half to even.
-          if (result > 0 || (result == 0 && (digit % 2) != 0))
-            ++data[num_digits - 1];
-        }
-        buf.try_resize(to_unsigned(num_digits));
-        exp10 -= num_digits - 1;
-        return;
-      }
-      numerator *= 10;
-      lower *= 10;
-      if (upper != &lower) *upper *= 10;
-    }
-  }
-  // Generate the given number of digits.
-  exp10 -= num_digits - 1;
-  if (num_digits == 0) {
-    denominator *= 10;
-    auto digit = add_compare(numerator, numerator, denominator) > 0 ? '1' : '0';
-    buf.push_back(digit);
-    return;
-  }
-  buf.try_resize(to_unsigned(num_digits));
-  for (int i = 0; i < num_digits - 1; ++i) {
-    int digit = numerator.divmod_assign(denominator);
-    buf[i] = static_cast<char>('0' + digit);
-    numerator *= 10;
-  }
-  int digit = numerator.divmod_assign(denominator);
-  auto result = add_compare(numerator, numerator, denominator);
-  if (result > 0 || (result == 0 && (digit % 2) != 0)) {
-    if (digit == 9) {
-      const auto overflow = '0' + 10;
-      buf[num_digits - 1] = overflow;
-      // Propagate the carry.
-      for (int i = num_digits - 1; i > 0 && buf[i] == overflow; --i) {
-        buf[i] = '0';
-        ++buf[i - 1];
-      }
-      if (buf[0] == overflow) {
-        buf[0] = '1';
-        ++exp10;
-      }
-      return;
-    }
-    ++digit;
-  }
-  buf[num_digits - 1] = static_cast<char>('0' + digit);
-}
-
-template <typename Float>
-FMT_HEADER_ONLY_CONSTEXPR20 int format_float(Float value, int precision,
-                                             float_specs specs,
-                                             buffer<char>& buf) {
-  // float is passed as double to reduce the number of instantiations.
-  static_assert(!std::is_same<Float, float>::value, "");
-  FMT_ASSERT(value >= 0, "value is negative");
-
-  const bool fixed = specs.format == float_format::fixed;
-  if (value <= 0) {  // <= instead of == to silence a warning.
-    if (precision <= 0 || !fixed) {
-      buf.push_back('0');
-      return 0;
-    }
-    buf.try_resize(to_unsigned(precision));
-    fill_n(buf.data(), precision, '0');
-    return -precision;
-  }
-
-  if (specs.fallback) return snprintf_float(value, precision, specs, buf);
-
-  if (!is_constant_evaluated() && precision < 0) {
-    // Use Dragonbox for the shortest format.
-    if (specs.binary32) {
-      auto dec = dragonbox::to_decimal(static_cast<float>(value));
-      write<char>(buffer_appender<char>(buf), dec.significand);
-      return dec.exponent;
-    }
-    auto dec = dragonbox::to_decimal(static_cast<double>(value));
-    write<char>(buffer_appender<char>(buf), dec.significand);
-    return dec.exponent;
-  }
-
-  int exp = 0;
-  bool use_dragon = true;
-  if (is_fast_float<Float>()) {
-    // Use Grisu + Dragon4 for the given precision:
-    // https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf.
-    const int min_exp = -60;  // alpha in Grisu.
-    int cached_exp10 = 0;     // K in Grisu.
-    fp normalized = normalize(fp(value));
-    const auto cached_pow = get_cached_power(
-        min_exp - (normalized.e + fp::num_significand_bits), cached_exp10);
-    normalized = normalized * cached_pow;
-    gen_digits_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
-    if (grisu_gen_digits(normalized, 1, exp, handler) != digits::error &&
-        !is_constant_evaluated()) {
-      exp += handler.exp10;
-      buf.try_resize(to_unsigned(handler.size));
-      use_dragon = false;
-    } else {
-      exp += handler.size - cached_exp10 - 1;
-      precision = handler.precision;
-    }
-  }
-  if (use_dragon) {
-    auto f = fp();
-    bool is_predecessor_closer =
-        specs.binary32 ? f.assign(static_cast<float>(value)) : f.assign(value);
-    // Limit precision to the maximum possible number of significant digits in
-    // an IEEE754 double because we don't need to generate zeros.
-    const int max_double_digits = 767;
-    if (precision > max_double_digits) precision = max_double_digits;
-    format_dragon(f, is_predecessor_closer, precision, buf, exp);
-  }
-  if (!fixed && !specs.showpoint) {
-    // Remove trailing zeros.
-    auto num_digits = buf.size();
-    while (num_digits > 0 && buf[num_digits - 1] == '0') {
-      --num_digits;
-      ++exp;
-    }
-    buf.try_resize(num_digits);
-  }
-  return exp;
-}
-
-template <typename T>
-int snprintf_float(T value, int precision, float_specs specs,
-                   buffer<char>& buf) {
-  // Buffer capacity must be non-zero, otherwise MSVC's vsnprintf_s will fail.
-  FMT_ASSERT(buf.capacity() > buf.size(), "empty buffer");
-  static_assert(!std::is_same<T, float>::value, "");
-
-  // Subtract 1 to account for the difference in precision since we use %e for
-  // both general and exponent format.
-  if (specs.format == float_format::general ||
-      specs.format == float_format::exp)
-    precision = (precision >= 0 ? precision : 6) - 1;
-
-  // Build the format string.
-  enum { max_format_size = 7 };  // The longest format is "%#.*Le".
-  char format[max_format_size];
-  char* format_ptr = format;
-  *format_ptr++ = '%';
-  if (specs.showpoint && specs.format == float_format::hex) *format_ptr++ = '#';
-  if (precision >= 0) {
-    *format_ptr++ = '.';
-    *format_ptr++ = '*';
-  }
-  if (std::is_same<T, long double>()) *format_ptr++ = 'L';
-  *format_ptr++ = specs.format != float_format::hex
-                      ? (specs.format == float_format::fixed ? 'f' : 'e')
-                      : (specs.upper ? 'A' : 'a');
-  *format_ptr = '\0';
-
-  // Format using snprintf.
-  auto offset = buf.size();
-  for (;;) {
-    auto begin = buf.data() + offset;
-    auto capacity = buf.capacity() - offset;
-#ifdef FMT_FUZZ
-    if (precision > 100000)
-      throw std::runtime_error(
-          "fuzz mode - avoid large allocation inside snprintf");
-#endif
-    // Suppress the warning about a nonliteral format string.
-    // Cannot use auto because of a bug in MinGW (#1532).
-    int (*snprintf_ptr)(char*, size_t, const char*, ...) = FMT_SNPRINTF;
-    int result = precision >= 0
-                     ? snprintf_ptr(begin, capacity, format, precision, value)
-                     : snprintf_ptr(begin, capacity, format, value);
-    if (result < 0) {
-      // The buffer will grow exponentially.
-      buf.try_reserve(buf.capacity() + 1);
-      continue;
-    }
-    auto size = to_unsigned(result);
-    // Size equal to capacity means that the last character was truncated.
-    if (size >= capacity) {
-      buf.try_reserve(size + offset + 1);  // Add 1 for the terminating '\0'.
-      continue;
-    }
-    auto is_digit = [](char c) { return c >= '0' && c <= '9'; };
-    if (specs.format == float_format::fixed) {
-      if (precision == 0) {
-        buf.try_resize(size);
-        return 0;
-      }
-      // Find and remove the decimal point.
-      auto end = begin + size, p = end;
-      do {
-        --p;
-      } while (is_digit(*p));
-      int fraction_size = static_cast<int>(end - p - 1);
-      std::memmove(p, p + 1, to_unsigned(fraction_size));
-      buf.try_resize(size - 1);
-      return -fraction_size;
-    }
-    if (specs.format == float_format::hex) {
-      buf.try_resize(size + offset);
-      return 0;
-    }
-    // Find and parse the exponent.
-    auto end = begin + size, exp_pos = end;
-    do {
-      --exp_pos;
-    } while (*exp_pos != 'e');
-    char sign = exp_pos[1];
-    FMT_ASSERT(sign == '+' || sign == '-', "");
-    int exp = 0;
-    auto p = exp_pos + 2;  // Skip 'e' and sign.
-    do {
-      FMT_ASSERT(is_digit(*p), "");
-      exp = exp * 10 + (*p++ - '0');
-    } while (p != end);
-    if (sign == '-') exp = -exp;
-    int fraction_size = 0;
-    if (exp_pos != begin + 1) {
-      // Remove trailing zeros.
-      auto fraction_end = exp_pos - 1;
-      while (*fraction_end == '0') --fraction_end;
-      // Move the fractional part left to get rid of the decimal point.
-      fraction_size = static_cast<int>(fraction_end - begin - 1);
-      std::memmove(begin + 1, begin + 2, to_unsigned(fraction_size));
-    }
-    buf.try_resize(to_unsigned(fraction_size) + offset + 1);
-    return exp - fraction_size;
-  }
-}
 }  // namespace detail
 
 template <> struct formatter<detail::bigint> {
-  FMT_CONSTEXPR format_parse_context::iterator parse(
-      format_parse_context& ctx) {
+  FMT_CONSTEXPR auto parse(format_parse_context& ctx)
+      -> format_parse_context::iterator {
     return ctx.begin();
   }
 
-  format_context::iterator format(const detail::bigint& n,
-                                  format_context& ctx) {
+  auto format(const detail::bigint& n, format_context& ctx) const
+      -> format_context::iterator {
     auto out = ctx.out();
     bool first = true;
     for (auto i = n.bigits_.size(); i > 0; --i) {
@@ -2560,7 +1421,7 @@ FMT_FUNC detail::utf8_to_utf16::utf8_to_utf16(string_view s) {
 }
 
 FMT_FUNC void format_system_error(detail::buffer<char>& out, int error_code,
-                                  const char* message) FMT_NOEXCEPT {
+                                  const char* message) noexcept {
   FMT_TRY {
     auto ec = std::error_code(error_code, std::generic_category());
     write(std::back_inserter(out), std::system_error(ec, message).what());
@@ -2571,16 +1432,10 @@ FMT_FUNC void format_system_error(detail::buffer<char>& out, int error_code,
 }
 
 FMT_FUNC void report_system_error(int error_code,
-                                  const char* message) FMT_NOEXCEPT {
+                                  const char* message) noexcept {
   report_error(format_system_error, error_code, message);
 }
 
-// DEPRECATED!
-// This function is defined here and not inline for ABI compatiblity.
-FMT_FUNC void detail::error_handler::on_error(const char* message) {
-  throw_format_error(message);
-}
-
 FMT_FUNC std::string vformat(string_view fmt, format_args args) {
   // Don't optimize the "{}" case to keep the binary size small and because it
   // can be better optimized in fmt::format anyway.
@@ -2589,55 +1444,238 @@ FMT_FUNC std::string vformat(string_view fmt, format_args args) {
   return to_string(buffer);
 }
 
-#ifdef _WIN32
 namespace detail {
+#ifndef _WIN32
+FMT_FUNC bool write_console(std::FILE*, string_view) { return false; }
+#else
 using dword = conditional_t<sizeof(long) == 4, unsigned long, unsigned>;
 extern "C" __declspec(dllimport) int __stdcall WriteConsoleW(  //
     void*, const void*, dword, dword*, void*);
-}  // namespace detail
-#endif
 
-namespace detail {
-FMT_FUNC void print(std::FILE* f, string_view text) {
-#ifdef _WIN32
+FMT_FUNC bool write_console(std::FILE* f, string_view text) {
   auto fd = _fileno(f);
-  if (_isatty(fd)) {
-    detail::utf8_to_utf16 u16(string_view(text.data(), text.size()));
-    auto written = detail::dword();
-    if (detail::WriteConsoleW(reinterpret_cast<void*>(_get_osfhandle(fd)),
-                              u16.c_str(), static_cast<uint32_t>(u16.size()),
-                              &written, nullptr)) {
-      return;
-    }
-    // Fallback to fwrite on failure. It can happen if the output has been
-    // redirected to NUL.
-  }
+  if (!_isatty(fd)) return false;
+  auto u16 = utf8_to_utf16(text);
+  auto written = dword();
+  return WriteConsoleW(reinterpret_cast<void*>(_get_osfhandle(fd)), u16.c_str(),
+                       static_cast<uint32_t>(u16.size()), &written, nullptr);
+}
+
+// Print assuming legacy (non-Unicode) encoding.
+FMT_FUNC void vprint_mojibake(std::FILE* f, string_view fmt, format_args args) {
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt,
+                     basic_format_args<buffer_context<char>>(args));
+  fwrite_fully(buffer.data(), 1, buffer.size(), f);
+}
 #endif
-  detail::fwrite_fully(text.data(), 1, text.size(), f);
+
+FMT_FUNC void print(std::FILE* f, string_view text) {
+  if (!write_console(f, text)) fwrite_fully(text.data(), 1, text.size(), f);
 }
 }  // namespace detail
 
-FMT_FUNC void vprint(std::FILE* f, string_view format_str, format_args args) {
-  memory_buffer buffer;
-  detail::vformat_to(buffer, format_str, args);
+FMT_FUNC void vprint(std::FILE* f, string_view fmt, format_args args) {
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, fmt, args);
   detail::print(f, {buffer.data(), buffer.size()});
 }
 
-#ifdef _WIN32
-// Print assuming legacy (non-Unicode) encoding.
-FMT_FUNC void detail::vprint_mojibake(std::FILE* f, string_view format_str,
-                                      format_args args) {
-  memory_buffer buffer;
-  detail::vformat_to(buffer, format_str,
-                     basic_format_args<buffer_context<char>>(args));
-  fwrite_fully(buffer.data(), 1, buffer.size(), f);
+FMT_FUNC void vprint(string_view fmt, format_args args) {
+  vprint(stdout, fmt, args);
+}
+
+namespace detail {
+
+struct singleton {
+  unsigned char upper;
+  unsigned char lower_count;
+};
+
+inline auto is_printable(uint16_t x, const singleton* singletons,
+                         size_t singletons_size,
+                         const unsigned char* singleton_lowers,
+                         const unsigned char* normal, size_t normal_size)
+    -> bool {
+  auto upper = x >> 8;
+  auto lower_start = 0;
+  for (size_t i = 0; i < singletons_size; ++i) {
+    auto s = singletons[i];
+    auto lower_end = lower_start + s.lower_count;
+    if (upper < s.upper) break;
+    if (upper == s.upper) {
+      for (auto j = lower_start; j < lower_end; ++j) {
+        if (singleton_lowers[j] == (x & 0xff)) return false;
+      }
+    }
+    lower_start = lower_end;
+  }
+
+  auto xsigned = static_cast<int>(x);
+  auto current = true;
+  for (size_t i = 0; i < normal_size; ++i) {
+    auto v = static_cast<int>(normal[i]);
+    auto len = (v & 0x80) != 0 ? (v & 0x7f) << 8 | normal[++i] : v;
+    xsigned -= len;
+    if (xsigned < 0) break;
+    current = !current;
+  }
+  return current;
 }
-#endif
 
-FMT_FUNC void vprint(string_view format_str, format_args args) {
-  vprint(stdout, format_str, args);
+// This code is generated by support/printable.py.
+FMT_FUNC auto is_printable(uint32_t cp) -> bool {
+  static constexpr singleton singletons0[] = {
+      {0x00, 1},  {0x03, 5},  {0x05, 6},  {0x06, 3},  {0x07, 6},  {0x08, 8},
+      {0x09, 17}, {0x0a, 28}, {0x0b, 25}, {0x0c, 20}, {0x0d, 16}, {0x0e, 13},
+      {0x0f, 4},  {0x10, 3},  {0x12, 18}, {0x13, 9},  {0x16, 1},  {0x17, 5},
+      {0x18, 2},  {0x19, 3},  {0x1a, 7},  {0x1c, 2},  {0x1d, 1},  {0x1f, 22},
+      {0x20, 3},  {0x2b, 3},  {0x2c, 2},  {0x2d, 11}, {0x2e, 1},  {0x30, 3},
+      {0x31, 2},  {0x32, 1},  {0xa7, 2},  {0xa9, 2},  {0xaa, 4},  {0xab, 8},
+      {0xfa, 2},  {0xfb, 5},  {0xfd, 4},  {0xfe, 3},  {0xff, 9},
+  };
+  static constexpr unsigned char singletons0_lower[] = {
+      0xad, 0x78, 0x79, 0x8b, 0x8d, 0xa2, 0x30, 0x57, 0x58, 0x8b, 0x8c, 0x90,
+      0x1c, 0x1d, 0xdd, 0x0e, 0x0f, 0x4b, 0x4c, 0xfb, 0xfc, 0x2e, 0x2f, 0x3f,
+      0x5c, 0x5d, 0x5f, 0xb5, 0xe2, 0x84, 0x8d, 0x8e, 0x91, 0x92, 0xa9, 0xb1,
+      0xba, 0xbb, 0xc5, 0xc6, 0xc9, 0xca, 0xde, 0xe4, 0xe5, 0xff, 0x00, 0x04,
+      0x11, 0x12, 0x29, 0x31, 0x34, 0x37, 0x3a, 0x3b, 0x3d, 0x49, 0x4a, 0x5d,
+      0x84, 0x8e, 0x92, 0xa9, 0xb1, 0xb4, 0xba, 0xbb, 0xc6, 0xca, 0xce, 0xcf,
+      0xe4, 0xe5, 0x00, 0x04, 0x0d, 0x0e, 0x11, 0x12, 0x29, 0x31, 0x34, 0x3a,
+      0x3b, 0x45, 0x46, 0x49, 0x4a, 0x5e, 0x64, 0x65, 0x84, 0x91, 0x9b, 0x9d,
+      0xc9, 0xce, 0xcf, 0x0d, 0x11, 0x29, 0x45, 0x49, 0x57, 0x64, 0x65, 0x8d,
+      0x91, 0xa9, 0xb4, 0xba, 0xbb, 0xc5, 0xc9, 0xdf, 0xe4, 0xe5, 0xf0, 0x0d,
+      0x11, 0x45, 0x49, 0x64, 0x65, 0x80, 0x84, 0xb2, 0xbc, 0xbe, 0xbf, 0xd5,
+      0xd7, 0xf0, 0xf1, 0x83, 0x85, 0x8b, 0xa4, 0xa6, 0xbe, 0xbf, 0xc5, 0xc7,
+      0xce, 0xcf, 0xda, 0xdb, 0x48, 0x98, 0xbd, 0xcd, 0xc6, 0xce, 0xcf, 0x49,
+      0x4e, 0x4f, 0x57, 0x59, 0x5e, 0x5f, 0x89, 0x8e, 0x8f, 0xb1, 0xb6, 0xb7,
+      0xbf, 0xc1, 0xc6, 0xc7, 0xd7, 0x11, 0x16, 0x17, 0x5b, 0x5c, 0xf6, 0xf7,
+      0xfe, 0xff, 0x80, 0x0d, 0x6d, 0x71, 0xde, 0xdf, 0x0e, 0x0f, 0x1f, 0x6e,
+      0x6f, 0x1c, 0x1d, 0x5f, 0x7d, 0x7e, 0xae, 0xaf, 0xbb, 0xbc, 0xfa, 0x16,
+      0x17, 0x1e, 0x1f, 0x46, 0x47, 0x4e, 0x4f, 0x58, 0x5a, 0x5c, 0x5e, 0x7e,
+      0x7f, 0xb5, 0xc5, 0xd4, 0xd5, 0xdc, 0xf0, 0xf1, 0xf5, 0x72, 0x73, 0x8f,
+      0x74, 0x75, 0x96, 0x2f, 0x5f, 0x26, 0x2e, 0x2f, 0xa7, 0xaf, 0xb7, 0xbf,
+      0xc7, 0xcf, 0xd7, 0xdf, 0x9a, 0x40, 0x97, 0x98, 0x30, 0x8f, 0x1f, 0xc0,
+      0xc1, 0xce, 0xff, 0x4e, 0x4f, 0x5a, 0x5b, 0x07, 0x08, 0x0f, 0x10, 0x27,
+      0x2f, 0xee, 0xef, 0x6e, 0x6f, 0x37, 0x3d, 0x3f, 0x42, 0x45, 0x90, 0x91,
+      0xfe, 0xff, 0x53, 0x67, 0x75, 0xc8, 0xc9, 0xd0, 0xd1, 0xd8, 0xd9, 0xe7,
+      0xfe, 0xff,
+  };
+  static constexpr singleton singletons1[] = {
+      {0x00, 6},  {0x01, 1}, {0x03, 1},  {0x04, 2}, {0x08, 8},  {0x09, 2},
+      {0x0a, 5},  {0x0b, 2}, {0x0e, 4},  {0x10, 1}, {0x11, 2},  {0x12, 5},
+      {0x13, 17}, {0x14, 1}, {0x15, 2},  {0x17, 2}, {0x19, 13}, {0x1c, 5},
+      {0x1d, 8},  {0x24, 1}, {0x6a, 3},  {0x6b, 2}, {0xbc, 2},  {0xd1, 2},
+      {0xd4, 12}, {0xd5, 9}, {0xd6, 2},  {0xd7, 2}, {0xda, 1},  {0xe0, 5},
+      {0xe1, 2},  {0xe8, 2}, {0xee, 32}, {0xf0, 4}, {0xf8, 2},  {0xf9, 2},
+      {0xfa, 2},  {0xfb, 1},
+  };
+  static constexpr unsigned char singletons1_lower[] = {
+      0x0c, 0x27, 0x3b, 0x3e, 0x4e, 0x4f, 0x8f, 0x9e, 0x9e, 0x9f, 0x06, 0x07,
+      0x09, 0x36, 0x3d, 0x3e, 0x56, 0xf3, 0xd0, 0xd1, 0x04, 0x14, 0x18, 0x36,
+      0x37, 0x56, 0x57, 0x7f, 0xaa, 0xae, 0xaf, 0xbd, 0x35, 0xe0, 0x12, 0x87,
+      0x89, 0x8e, 0x9e, 0x04, 0x0d, 0x0e, 0x11, 0x12, 0x29, 0x31, 0x34, 0x3a,
+      0x45, 0x46, 0x49, 0x4a, 0x4e, 0x4f, 0x64, 0x65, 0x5c, 0xb6, 0xb7, 0x1b,
+      0x1c, 0x07, 0x08, 0x0a, 0x0b, 0x14, 0x17, 0x36, 0x39, 0x3a, 0xa8, 0xa9,
+      0xd8, 0xd9, 0x09, 0x37, 0x90, 0x91, 0xa8, 0x07, 0x0a, 0x3b, 0x3e, 0x66,
+      0x69, 0x8f, 0x92, 0x6f, 0x5f, 0xee, 0xef, 0x5a, 0x62, 0x9a, 0x9b, 0x27,
+      0x28, 0x55, 0x9d, 0xa0, 0xa1, 0xa3, 0xa4, 0xa7, 0xa8, 0xad, 0xba, 0xbc,
+      0xc4, 0x06, 0x0b, 0x0c, 0x15, 0x1d, 0x3a, 0x3f, 0x45, 0x51, 0xa6, 0xa7,
+      0xcc, 0xcd, 0xa0, 0x07, 0x19, 0x1a, 0x22, 0x25, 0x3e, 0x3f, 0xc5, 0xc6,
+      0x04, 0x20, 0x23, 0x25, 0x26, 0x28, 0x33, 0x38, 0x3a, 0x48, 0x4a, 0x4c,
+      0x50, 0x53, 0x55, 0x56, 0x58, 0x5a, 0x5c, 0x5e, 0x60, 0x63, 0x65, 0x66,
+      0x6b, 0x73, 0x78, 0x7d, 0x7f, 0x8a, 0xa4, 0xaa, 0xaf, 0xb0, 0xc0, 0xd0,
+      0xae, 0xaf, 0x79, 0xcc, 0x6e, 0x6f, 0x93,
+  };
+  static constexpr unsigned char normal0[] = {
+      0x00, 0x20, 0x5f, 0x22, 0x82, 0xdf, 0x04, 0x82, 0x44, 0x08, 0x1b, 0x04,
+      0x06, 0x11, 0x81, 0xac, 0x0e, 0x80, 0xab, 0x35, 0x28, 0x0b, 0x80, 0xe0,
+      0x03, 0x19, 0x08, 0x01, 0x04, 0x2f, 0x04, 0x34, 0x04, 0x07, 0x03, 0x01,
+      0x07, 0x06, 0x07, 0x11, 0x0a, 0x50, 0x0f, 0x12, 0x07, 0x55, 0x07, 0x03,
+      0x04, 0x1c, 0x0a, 0x09, 0x03, 0x08, 0x03, 0x07, 0x03, 0x02, 0x03, 0x03,
+      0x03, 0x0c, 0x04, 0x05, 0x03, 0x0b, 0x06, 0x01, 0x0e, 0x15, 0x05, 0x3a,
+      0x03, 0x11, 0x07, 0x06, 0x05, 0x10, 0x07, 0x57, 0x07, 0x02, 0x07, 0x15,
+      0x0d, 0x50, 0x04, 0x43, 0x03, 0x2d, 0x03, 0x01, 0x04, 0x11, 0x06, 0x0f,
+      0x0c, 0x3a, 0x04, 0x1d, 0x25, 0x5f, 0x20, 0x6d, 0x04, 0x6a, 0x25, 0x80,
+      0xc8, 0x05, 0x82, 0xb0, 0x03, 0x1a, 0x06, 0x82, 0xfd, 0x03, 0x59, 0x07,
+      0x15, 0x0b, 0x17, 0x09, 0x14, 0x0c, 0x14, 0x0c, 0x6a, 0x06, 0x0a, 0x06,
+      0x1a, 0x06, 0x59, 0x07, 0x2b, 0x05, 0x46, 0x0a, 0x2c, 0x04, 0x0c, 0x04,
+      0x01, 0x03, 0x31, 0x0b, 0x2c, 0x04, 0x1a, 0x06, 0x0b, 0x03, 0x80, 0xac,
+      0x06, 0x0a, 0x06, 0x21, 0x3f, 0x4c, 0x04, 0x2d, 0x03, 0x74, 0x08, 0x3c,
+      0x03, 0x0f, 0x03, 0x3c, 0x07, 0x38, 0x08, 0x2b, 0x05, 0x82, 0xff, 0x11,
+      0x18, 0x08, 0x2f, 0x11, 0x2d, 0x03, 0x20, 0x10, 0x21, 0x0f, 0x80, 0x8c,
+      0x04, 0x82, 0x97, 0x19, 0x0b, 0x15, 0x88, 0x94, 0x05, 0x2f, 0x05, 0x3b,
+      0x07, 0x02, 0x0e, 0x18, 0x09, 0x80, 0xb3, 0x2d, 0x74, 0x0c, 0x80, 0xd6,
+      0x1a, 0x0c, 0x05, 0x80, 0xff, 0x05, 0x80, 0xdf, 0x0c, 0xee, 0x0d, 0x03,
+      0x84, 0x8d, 0x03, 0x37, 0x09, 0x81, 0x5c, 0x14, 0x80, 0xb8, 0x08, 0x80,
+      0xcb, 0x2a, 0x38, 0x03, 0x0a, 0x06, 0x38, 0x08, 0x46, 0x08, 0x0c, 0x06,
+      0x74, 0x0b, 0x1e, 0x03, 0x5a, 0x04, 0x59, 0x09, 0x80, 0x83, 0x18, 0x1c,
+      0x0a, 0x16, 0x09, 0x4c, 0x04, 0x80, 0x8a, 0x06, 0xab, 0xa4, 0x0c, 0x17,
+      0x04, 0x31, 0xa1, 0x04, 0x81, 0xda, 0x26, 0x07, 0x0c, 0x05, 0x05, 0x80,
+      0xa5, 0x11, 0x81, 0x6d, 0x10, 0x78, 0x28, 0x2a, 0x06, 0x4c, 0x04, 0x80,
+      0x8d, 0x04, 0x80, 0xbe, 0x03, 0x1b, 0x03, 0x0f, 0x0d,
+  };
+  static constexpr unsigned char normal1[] = {
+      0x5e, 0x22, 0x7b, 0x05, 0x03, 0x04, 0x2d, 0x03, 0x66, 0x03, 0x01, 0x2f,
+      0x2e, 0x80, 0x82, 0x1d, 0x03, 0x31, 0x0f, 0x1c, 0x04, 0x24, 0x09, 0x1e,
+      0x05, 0x2b, 0x05, 0x44, 0x04, 0x0e, 0x2a, 0x80, 0xaa, 0x06, 0x24, 0x04,
+      0x24, 0x04, 0x28, 0x08, 0x34, 0x0b, 0x01, 0x80, 0x90, 0x81, 0x37, 0x09,
+      0x16, 0x0a, 0x08, 0x80, 0x98, 0x39, 0x03, 0x63, 0x08, 0x09, 0x30, 0x16,
+      0x05, 0x21, 0x03, 0x1b, 0x05, 0x01, 0x40, 0x38, 0x04, 0x4b, 0x05, 0x2f,
+      0x04, 0x0a, 0x07, 0x09, 0x07, 0x40, 0x20, 0x27, 0x04, 0x0c, 0x09, 0x36,
+      0x03, 0x3a, 0x05, 0x1a, 0x07, 0x04, 0x0c, 0x07, 0x50, 0x49, 0x37, 0x33,
+      0x0d, 0x33, 0x07, 0x2e, 0x08, 0x0a, 0x81, 0x26, 0x52, 0x4e, 0x28, 0x08,
+      0x2a, 0x56, 0x1c, 0x14, 0x17, 0x09, 0x4e, 0x04, 0x1e, 0x0f, 0x43, 0x0e,
+      0x19, 0x07, 0x0a, 0x06, 0x48, 0x08, 0x27, 0x09, 0x75, 0x0b, 0x3f, 0x41,
+      0x2a, 0x06, 0x3b, 0x05, 0x0a, 0x06, 0x51, 0x06, 0x01, 0x05, 0x10, 0x03,
+      0x05, 0x80, 0x8b, 0x62, 0x1e, 0x48, 0x08, 0x0a, 0x80, 0xa6, 0x5e, 0x22,
+      0x45, 0x0b, 0x0a, 0x06, 0x0d, 0x13, 0x39, 0x07, 0x0a, 0x36, 0x2c, 0x04,
+      0x10, 0x80, 0xc0, 0x3c, 0x64, 0x53, 0x0c, 0x48, 0x09, 0x0a, 0x46, 0x45,
+      0x1b, 0x48, 0x08, 0x53, 0x1d, 0x39, 0x81, 0x07, 0x46, 0x0a, 0x1d, 0x03,
+      0x47, 0x49, 0x37, 0x03, 0x0e, 0x08, 0x0a, 0x06, 0x39, 0x07, 0x0a, 0x81,
+      0x36, 0x19, 0x80, 0xb7, 0x01, 0x0f, 0x32, 0x0d, 0x83, 0x9b, 0x66, 0x75,
+      0x0b, 0x80, 0xc4, 0x8a, 0xbc, 0x84, 0x2f, 0x8f, 0xd1, 0x82, 0x47, 0xa1,
+      0xb9, 0x82, 0x39, 0x07, 0x2a, 0x04, 0x02, 0x60, 0x26, 0x0a, 0x46, 0x0a,
+      0x28, 0x05, 0x13, 0x82, 0xb0, 0x5b, 0x65, 0x4b, 0x04, 0x39, 0x07, 0x11,
+      0x40, 0x05, 0x0b, 0x02, 0x0e, 0x97, 0xf8, 0x08, 0x84, 0xd6, 0x2a, 0x09,
+      0xa2, 0xf7, 0x81, 0x1f, 0x31, 0x03, 0x11, 0x04, 0x08, 0x81, 0x8c, 0x89,
+      0x04, 0x6b, 0x05, 0x0d, 0x03, 0x09, 0x07, 0x10, 0x93, 0x60, 0x80, 0xf6,
+      0x0a, 0x73, 0x08, 0x6e, 0x17, 0x46, 0x80, 0x9a, 0x14, 0x0c, 0x57, 0x09,
+      0x19, 0x80, 0x87, 0x81, 0x47, 0x03, 0x85, 0x42, 0x0f, 0x15, 0x85, 0x50,
+      0x2b, 0x80, 0xd5, 0x2d, 0x03, 0x1a, 0x04, 0x02, 0x81, 0x70, 0x3a, 0x05,
+      0x01, 0x85, 0x00, 0x80, 0xd7, 0x29, 0x4c, 0x04, 0x0a, 0x04, 0x02, 0x83,
+      0x11, 0x44, 0x4c, 0x3d, 0x80, 0xc2, 0x3c, 0x06, 0x01, 0x04, 0x55, 0x05,
+      0x1b, 0x34, 0x02, 0x81, 0x0e, 0x2c, 0x04, 0x64, 0x0c, 0x56, 0x0a, 0x80,
+      0xae, 0x38, 0x1d, 0x0d, 0x2c, 0x04, 0x09, 0x07, 0x02, 0x0e, 0x06, 0x80,
+      0x9a, 0x83, 0xd8, 0x08, 0x0d, 0x03, 0x0d, 0x03, 0x74, 0x0c, 0x59, 0x07,
+      0x0c, 0x14, 0x0c, 0x04, 0x38, 0x08, 0x0a, 0x06, 0x28, 0x08, 0x22, 0x4e,
+      0x81, 0x54, 0x0c, 0x15, 0x03, 0x03, 0x05, 0x07, 0x09, 0x19, 0x07, 0x07,
+      0x09, 0x03, 0x0d, 0x07, 0x29, 0x80, 0xcb, 0x25, 0x0a, 0x84, 0x06,
+  };
+  auto lower = static_cast<uint16_t>(cp);
+  if (cp < 0x10000) {
+    return is_printable(lower, singletons0,
+                        sizeof(singletons0) / sizeof(*singletons0),
+                        singletons0_lower, normal0, sizeof(normal0));
+  }
+  if (cp < 0x20000) {
+    return is_printable(lower, singletons1,
+                        sizeof(singletons1) / sizeof(*singletons1),
+                        singletons1_lower, normal1, sizeof(normal1));
+  }
+  if (0x2a6de <= cp && cp < 0x2a700) return false;
+  if (0x2b735 <= cp && cp < 0x2b740) return false;
+  if (0x2b81e <= cp && cp < 0x2b820) return false;
+  if (0x2cea2 <= cp && cp < 0x2ceb0) return false;
+  if (0x2ebe1 <= cp && cp < 0x2f800) return false;
+  if (0x2fa1e <= cp && cp < 0x30000) return false;
+  if (0x3134b <= cp && cp < 0xe0100) return false;
+  if (0xe01f0 <= cp && cp < 0x110000) return false;
+  return cp < 0x110000;
 }
 
+}  // namespace detail
+
 FMT_END_NAMESPACE
 
 #endif  // FMT_FORMAT_INL_H_
diff --git a/contrib/fmt/include/fmt/format.h b/contrib/fmt/include/fmt/format.h
index ee69651ca..ed8b29eba 100644
--- a/contrib/fmt/include/fmt/format.h
+++ b/contrib/fmt/include/fmt/format.h
@@ -1,45 +1,46 @@
 /*
- Formatting library for C++
-
- Copyright (c) 2012 - present, Victor Zverovich
-
- Permission is hereby granted, free of charge, to any person obtaining
- a copy of this software and associated documentation files (the
- "Software"), to deal in the Software without restriction, including
- without limitation the rights to use, copy, modify, merge, publish,
- distribute, sublicense, and/or sell copies of the Software, and to
- permit persons to whom the Software is furnished to do so, subject to
- the following conditions:
-
- The above copyright notice and this permission notice shall be
- included in all copies or substantial portions of the Software.
-
- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
- LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
- OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-
- --- Optional exception to the license ---
-
- As an exception, if, as a result of your compiling your source code, portions
- of this Software are embedded into a machine-executable object form of such
- source code, you may redistribute such embedded portions in such object form
- without including the above copyright and permission notices.
+  Formatting library for C++
+
+  Copyright (c) 2012 - present, Victor Zverovich
+
+  Permission is hereby granted, free of charge, to any person obtaining
+  a copy of this software and associated documentation files (the
+  "Software"), to deal in the Software without restriction, including
+  without limitation the rights to use, copy, modify, merge, publish,
+  distribute, sublicense, and/or sell copies of the Software, and to
+  permit persons to whom the Software is furnished to do so, subject to
+  the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+  --- Optional exception to the license ---
+
+  As an exception, if, as a result of your compiling your source code, portions
+  of this Software are embedded into a machine-executable object form of such
+  source code, you may redistribute such embedded portions in such object form
+  without including the above copyright and permission notices.
  */
 
 #ifndef FMT_FORMAT_H_
 #define FMT_FORMAT_H_
 
-#include <cmath>         // std::signbit
-#include <cstdint>       // uint32_t
-#include <limits>        // std::numeric_limits
-#include <memory>        // std::uninitialized_copy
-#include <stdexcept>     // std::runtime_error
-#include <system_error>  // std::system_error
-#include <utility>       // std::swap
+#include <cmath>             // std::signbit
+#include <cstdint>           // uint32_t
+#include <cstring>           // std::memcpy
+#include <initializer_list>  // std::initializer_list
+#include <limits>            // std::numeric_limits
+#include <memory>            // std::uninitialized_copy
+#include <stdexcept>         // std::runtime_error
+#include <system_error>      // std::system_error
 
 #ifdef __cpp_lib_bit_cast
 #  include <bit>  // std::bitcast
@@ -47,6 +48,36 @@
 
 #include "core.h"
 
+#ifndef FMT_BEGIN_DETAIL_NAMESPACE
+#  define FMT_BEGIN_DETAIL_NAMESPACE namespace detail {
+#  define FMT_END_DETAIL_NAMESPACE }
+#endif
+
+#if FMT_HAS_CPP17_ATTRIBUTE(fallthrough)
+#  define FMT_FALLTHROUGH [[fallthrough]]
+#elif defined(__clang__)
+#  define FMT_FALLTHROUGH [[clang::fallthrough]]
+#elif FMT_GCC_VERSION >= 700 && \
+    (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= 520)
+#  define FMT_FALLTHROUGH [[gnu::fallthrough]]
+#else
+#  define FMT_FALLTHROUGH
+#endif
+
+#ifndef FMT_DEPRECATED
+#  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VERSION >= 1900
+#    define FMT_DEPRECATED [[deprecated]]
+#  else
+#    if (defined(__GNUC__) && !defined(__LCC__)) || defined(__clang__)
+#      define FMT_DEPRECATED __attribute__((deprecated))
+#    elif FMT_MSC_VERSION
+#      define FMT_DEPRECATED __declspec(deprecated)
+#    else
+#      define FMT_DEPRECATED /* deprecated */
+#    endif
+#  endif
+#endif
+
 #if FMT_GCC_VERSION
 #  define FMT_GCC_VISIBILITY_HIDDEN __attribute__((visibility("hidden")))
 #else
@@ -71,15 +102,9 @@
 #  define FMT_NOINLINE
 #endif
 
-#if FMT_MSC_VER
-#  define FMT_MSC_DEFAULT = default
-#else
-#  define FMT_MSC_DEFAULT
-#endif
-
 #ifndef FMT_THROW
 #  if FMT_EXCEPTIONS
-#    if FMT_MSC_VER || FMT_NVCC
+#    if FMT_MSC_VERSION || defined(__NVCC__)
 FMT_BEGIN_NAMESPACE
 namespace detail {
 template <typename Exception> inline void do_throw(const Exception& x) {
@@ -118,17 +143,10 @@ FMT_END_NAMESPACE
 #  endif
 #endif
 
-// Workaround broken [[deprecated]] in the Intel, PGI and NVCC compilers.
-#if FMT_ICC_VERSION || defined(__PGI) || FMT_NVCC
-#  define FMT_DEPRECATED_ALIAS
-#else
-#  define FMT_DEPRECATED_ALIAS FMT_DEPRECATED
-#endif
-
 #ifndef FMT_USE_USER_DEFINED_LITERALS
 // EDG based compilers (Intel, NVIDIA, Elbrus, etc), GCC and MSVC support UDLs.
 #  if (FMT_HAS_FEATURE(cxx_user_literals) || FMT_GCC_VERSION >= 407 || \
-       FMT_MSC_VER >= 1900) &&                                         \
+       FMT_MSC_VERSION >= 1900) &&                                     \
       (!defined(__EDG_VERSION__) || __EDG_VERSION__ >= /* UDL feature */ 480)
 #    define FMT_USE_USER_DEFINED_LITERALS 1
 #  else
@@ -146,7 +164,7 @@ FMT_END_NAMESPACE
 
 // __builtin_clz is broken in clang with Microsoft CodeGen:
 // https://github.com/fmtlib/fmt/issues/519.
-#if !FMT_MSC_VER
+#if !FMT_MSC_VERSION
 #  if FMT_HAS_BUILTIN(__builtin_clz) || FMT_GCC_VERSION || FMT_ICC_VERSION
 #    define FMT_BUILTIN_CLZ(n) __builtin_clz(n)
 #  endif
@@ -158,22 +176,25 @@ FMT_END_NAMESPACE
 // __builtin_ctz is broken in Intel Compiler Classic on Windows:
 // https://github.com/fmtlib/fmt/issues/2510.
 #ifndef __ICL
-#  if FMT_HAS_BUILTIN(__builtin_ctz) || FMT_GCC_VERSION || FMT_ICC_VERSION
+#  if FMT_HAS_BUILTIN(__builtin_ctz) || FMT_GCC_VERSION || FMT_ICC_VERSION || \
+      defined(__NVCOMPILER)
 #    define FMT_BUILTIN_CTZ(n) __builtin_ctz(n)
 #  endif
-#  if FMT_HAS_BUILTIN(__builtin_ctzll) || FMT_GCC_VERSION || FMT_ICC_VERSION
+#  if FMT_HAS_BUILTIN(__builtin_ctzll) || FMT_GCC_VERSION || \
+      FMT_ICC_VERSION || defined(__NVCOMPILER)
 #    define FMT_BUILTIN_CTZLL(n) __builtin_ctzll(n)
 #  endif
 #endif
 
-#if FMT_MSC_VER
+#if FMT_MSC_VERSION
 #  include <intrin.h>  // _BitScanReverse[64], _BitScanForward[64], _umul128
 #endif
 
 // Some compilers masquerade as both MSVC and GCC-likes or otherwise support
 // __builtin_clz and __builtin_clzll, so only define FMT_BUILTIN_CLZ using the
 // MSVC intrinsics if the clz and clzll builtins are not available.
-#if FMT_MSC_VER && !defined(FMT_BUILTIN_CLZLL) && !defined(FMT_BUILTIN_CTZLL)
+#if FMT_MSC_VERSION && !defined(FMT_BUILTIN_CLZLL) && \
+    !defined(FMT_BUILTIN_CTZLL)
 FMT_BEGIN_NAMESPACE
 namespace detail {
 // Avoid Clang with Microsoft CodeGen's -Wunknown-pragmas warning.
@@ -204,7 +225,8 @@ inline auto clzll(uint64_t x) -> int {
   _BitScanReverse64(&r, x);
 #  else
   // Scan the high 32 bits.
-  if (_BitScanReverse(&r, static_cast<uint32_t>(x >> 32))) return 63 ^ (r + 32);
+  if (_BitScanReverse(&r, static_cast<uint32_t>(x >> 32)))
+    return 63 ^ static_cast<int>(r + 32);
   // Scan the low 32 bits.
   _BitScanReverse(&r, static_cast<uint32_t>(x));
 #  endif
@@ -243,15 +265,41 @@ inline auto ctzll(uint64_t x) -> int {
 FMT_END_NAMESPACE
 #endif
 
-#ifdef FMT_HEADER_ONLY
-#  define FMT_HEADER_ONLY_CONSTEXPR20 FMT_CONSTEXPR20
-#else
-#  define FMT_HEADER_ONLY_CONSTEXPR20
-#endif
-
 FMT_BEGIN_NAMESPACE
+
+template <typename...> struct disjunction : std::false_type {};
+template <typename P> struct disjunction<P> : P {};
+template <typename P1, typename... Pn>
+struct disjunction<P1, Pn...>
+    : conditional_t<bool(P1::value), P1, disjunction<Pn...>> {};
+
+template <typename...> struct conjunction : std::true_type {};
+template <typename P> struct conjunction<P> : P {};
+template <typename P1, typename... Pn>
+struct conjunction<P1, Pn...>
+    : conditional_t<bool(P1::value), conjunction<Pn...>, P1> {};
+
 namespace detail {
 
+FMT_CONSTEXPR inline void abort_fuzzing_if(bool condition) {
+  ignore_unused(condition);
+#ifdef FMT_FUZZ
+  if (condition) throw std::runtime_error("fuzzing limit reached");
+#endif
+}
+
+template <typename CharT, CharT... C> struct string_literal {
+  static constexpr CharT value[sizeof...(C)] = {C...};
+  constexpr operator basic_string_view<CharT>() const {
+    return {value, sizeof...(C)};
+  }
+};
+
+#if FMT_CPLUSPLUS < 201703L
+template <typename CharT, CharT... C>
+constexpr CharT string_literal<CharT, C...>::value[sizeof...(C)];
+#endif
+
 template <typename Streambuf> class formatbuf : public Streambuf {
  private:
   using char_type = typename Streambuf::char_type;
@@ -284,14 +332,14 @@ template <typename Streambuf> class formatbuf : public Streambuf {
 };
 
 // Implementation of std::bit_cast for pre-C++20.
-template <typename To, typename From>
+template <typename To, typename From, FMT_ENABLE_IF(sizeof(To) == sizeof(From))>
 FMT_CONSTEXPR20 auto bit_cast(const From& from) -> To {
-  static_assert(sizeof(To) == sizeof(From), "size mismatch");
 #ifdef __cpp_lib_bit_cast
   if (is_constant_evaluated()) return std::bit_cast<To>(from);
 #endif
   auto to = To();
-  std::memcpy(&to, &from, sizeof(to));
+  // The cast suppresses a bogus -Wclass-memaccess on GCC.
+  std::memcpy(static_cast<void*>(&to), &from, sizeof(to));
   return to;
 }
 
@@ -310,29 +358,125 @@ inline auto is_big_endian() -> bool {
 #endif
 }
 
-// A fallback implementation of uintptr_t for systems that lack it.
-struct fallback_uintptr {
-  unsigned char value[sizeof(void*)];
+class uint128_fallback {
+ private:
+  uint64_t lo_, hi_;
+
+  friend uint128_fallback umul128(uint64_t x, uint64_t y) noexcept;
+
+ public:
+  constexpr uint128_fallback(uint64_t hi, uint64_t lo) : lo_(lo), hi_(hi) {}
+  constexpr uint128_fallback(uint64_t value = 0) : lo_(value), hi_(0) {}
+
+  constexpr uint64_t high() const noexcept { return hi_; }
+  constexpr uint64_t low() const noexcept { return lo_; }
+
+  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  constexpr explicit operator T() const {
+    return static_cast<T>(lo_);
+  }
 
-  fallback_uintptr() = default;
-  explicit fallback_uintptr(const void* p) {
-    *this = bit_cast<fallback_uintptr>(p);
-    if (const_check(is_big_endian())) {
-      for (size_t i = 0, j = sizeof(void*) - 1; i < j; ++i, --j)
-        std::swap(value[i], value[j]);
+  friend constexpr auto operator==(const uint128_fallback& lhs,
+                                   const uint128_fallback& rhs) -> bool {
+    return lhs.hi_ == rhs.hi_ && lhs.lo_ == rhs.lo_;
+  }
+  friend constexpr auto operator!=(const uint128_fallback& lhs,
+                                   const uint128_fallback& rhs) -> bool {
+    return !(lhs == rhs);
+  }
+  friend constexpr auto operator>(const uint128_fallback& lhs,
+                                  const uint128_fallback& rhs) -> bool {
+    return lhs.hi_ != rhs.hi_ ? lhs.hi_ > rhs.hi_ : lhs.lo_ > rhs.lo_;
+  }
+  friend constexpr auto operator|(const uint128_fallback& lhs,
+                                  const uint128_fallback& rhs)
+      -> uint128_fallback {
+    return {lhs.hi_ | rhs.hi_, lhs.lo_ | rhs.lo_};
+  }
+  friend constexpr auto operator&(const uint128_fallback& lhs,
+                                  const uint128_fallback& rhs)
+      -> uint128_fallback {
+    return {lhs.hi_ & rhs.hi_, lhs.lo_ & rhs.lo_};
+  }
+  friend constexpr auto operator~(const uint128_fallback& n)
+      -> uint128_fallback {
+    return {~n.hi_, ~n.lo_};
+  }
+  friend auto operator+(const uint128_fallback& lhs,
+                        const uint128_fallback& rhs) -> uint128_fallback {
+    auto result = uint128_fallback(lhs);
+    result += rhs;
+    return result;
+  }
+  friend auto operator*(const uint128_fallback& lhs, uint32_t rhs)
+      -> uint128_fallback {
+    FMT_ASSERT(lhs.hi_ == 0, "");
+    uint64_t hi = (lhs.lo_ >> 32) * rhs;
+    uint64_t lo = (lhs.lo_ & ~uint32_t()) * rhs;
+    uint64_t new_lo = (hi << 32) + lo;
+    return {(hi >> 32) + (new_lo < lo ? 1 : 0), new_lo};
+  }
+  friend auto operator-(const uint128_fallback& lhs, uint64_t rhs)
+      -> uint128_fallback {
+    return {lhs.hi_ - (lhs.lo_ < rhs ? 1 : 0), lhs.lo_ - rhs};
+  }
+  FMT_CONSTEXPR auto operator>>(int shift) const -> uint128_fallback {
+    if (shift == 64) return {0, hi_};
+    if (shift > 64) return uint128_fallback(0, hi_) >> (shift - 64);
+    return {hi_ >> shift, (hi_ << (64 - shift)) | (lo_ >> shift)};
+  }
+  FMT_CONSTEXPR auto operator<<(int shift) const -> uint128_fallback {
+    if (shift == 64) return {lo_, 0};
+    if (shift > 64) return uint128_fallback(lo_, 0) << (shift - 64);
+    return {hi_ << shift | (lo_ >> (64 - shift)), (lo_ << shift)};
+  }
+  FMT_CONSTEXPR auto operator>>=(int shift) -> uint128_fallback& {
+    return *this = *this >> shift;
+  }
+  FMT_CONSTEXPR void operator+=(uint128_fallback n) {
+    uint64_t new_lo = lo_ + n.lo_;
+    uint64_t new_hi = hi_ + n.hi_ + (new_lo < lo_ ? 1 : 0);
+    FMT_ASSERT(new_hi >= hi_, "");
+    lo_ = new_lo;
+    hi_ = new_hi;
+  }
+  FMT_CONSTEXPR void operator&=(uint128_fallback n) {
+    lo_ &= n.lo_;
+    hi_ &= n.hi_;
+  }
+
+  FMT_CONSTEXPR20 uint128_fallback& operator+=(uint64_t n) noexcept {
+    if (is_constant_evaluated()) {
+      lo_ += n;
+      hi_ += (lo_ < n ? 1 : 0);
+      return *this;
     }
+#if FMT_HAS_BUILTIN(__builtin_addcll) && !defined(__ibmxl__)
+    unsigned long long carry;
+    lo_ = __builtin_addcll(lo_, n, 0, &carry);
+    hi_ += carry;
+#elif FMT_HAS_BUILTIN(__builtin_ia32_addcarryx_u64) && !defined(__ibmxl__)
+    unsigned long long result;
+    auto carry = __builtin_ia32_addcarryx_u64(0, lo_, n, &result);
+    lo_ = result;
+    hi_ += carry;
+#elif defined(_MSC_VER) && defined(_M_X64)
+    auto carry = _addcarry_u64(0, lo_, n, &lo_);
+    _addcarry_u64(carry, hi_, 0, &hi_);
+#else
+    lo_ += n;
+    hi_ += (lo_ < n ? 1 : 0);
+#endif
+    return *this;
   }
 };
+
+using uint128_t = conditional_t<FMT_USE_INT128, uint128_opt, uint128_fallback>;
+
 #ifdef UINTPTR_MAX
 using uintptr_t = ::uintptr_t;
-inline auto to_uintptr(const void* p) -> uintptr_t {
-  return bit_cast<uintptr_t>(p);
-}
 #else
-using uintptr_t = fallback_uintptr;
-inline auto to_uintptr(const void* p) -> fallback_uintptr {
-  return fallback_uintptr(p);
-}
+using uintptr_t = uint128_t;
 #endif
 
 // Returns the largest possible value for type T. Same as
@@ -344,16 +488,53 @@ template <typename T> constexpr auto num_bits() -> int {
   return std::numeric_limits<T>::digits;
 }
 // std::numeric_limits<T>::digits may return 0 for 128-bit ints.
-template <> constexpr auto num_bits<int128_t>() -> int { return 128; }
+template <> constexpr auto num_bits<int128_opt>() -> int { return 128; }
 template <> constexpr auto num_bits<uint128_t>() -> int { return 128; }
-template <> constexpr auto num_bits<fallback_uintptr>() -> int {
-  return static_cast<int>(sizeof(void*) *
-                          std::numeric_limits<unsigned char>::digits);
+
+// A heterogeneous bit_cast used for converting 96-bit long double to uint128_t
+// and 128-bit pointers to uint128_fallback.
+template <typename To, typename From, FMT_ENABLE_IF(sizeof(To) > sizeof(From))>
+inline auto bit_cast(const From& from) -> To {
+  constexpr auto size = static_cast<int>(sizeof(From) / sizeof(unsigned));
+  struct data_t {
+    unsigned value[static_cast<unsigned>(size)];
+  } data = bit_cast<data_t>(from);
+  auto result = To();
+  if (const_check(is_big_endian())) {
+    for (int i = 0; i < size; ++i)
+      result = (result << num_bits<unsigned>()) | data.value[i];
+  } else {
+    for (int i = size - 1; i >= 0; --i)
+      result = (result << num_bits<unsigned>()) | data.value[i];
+  }
+  return result;
+}
+
+template <typename UInt>
+FMT_CONSTEXPR20 inline auto countl_zero_fallback(UInt n) -> int {
+  int lz = 0;
+  constexpr UInt msb_mask = static_cast<UInt>(1) << (num_bits<UInt>() - 1);
+  for (; (n & msb_mask) == 0; n <<= 1) lz++;
+  return lz;
+}
+
+FMT_CONSTEXPR20 inline auto countl_zero(uint32_t n) -> int {
+#ifdef FMT_BUILTIN_CLZ
+  if (!is_constant_evaluated()) return FMT_BUILTIN_CLZ(n);
+#endif
+  return countl_zero_fallback(n);
+}
+
+FMT_CONSTEXPR20 inline auto countl_zero(uint64_t n) -> int {
+#ifdef FMT_BUILTIN_CLZLL
+  if (!is_constant_evaluated()) return FMT_BUILTIN_CLZLL(n);
+#endif
+  return countl_zero_fallback(n);
 }
 
 FMT_INLINE void assume(bool condition) {
   (void)condition;
-#if FMT_HAS_BUILTIN(__builtin_assume)
+#if FMT_HAS_BUILTIN(__builtin_assume) && !FMT_ICC_VERSION
   __builtin_assume(condition);
 #endif
 }
@@ -495,19 +676,24 @@ FMT_CONSTEXPR inline auto utf8_decode(const char* s, uint32_t* c, int* e)
   constexpr const int shiftc[] = {0, 18, 12, 6, 0};
   constexpr const int shifte[] = {0, 6, 4, 2, 0};
 
-  int len = code_point_length(s);
-  const char* next = s + len;
+  int len = "\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\1\0\0\0\0\0\0\0\0\2\2\2\2\3\3\4"
+      [static_cast<unsigned char>(*s) >> 3];
+  // Compute the pointer to the next character early so that the next
+  // iteration can start working on the next character. Neither Clang
+  // nor GCC figure out this reordering on their own.
+  const char* next = s + len + !len;
+
+  using uchar = unsigned char;
 
   // Assume a four-byte character and load four bytes. Unused bits are
   // shifted out.
-  *c = uint32_t(s[0] & masks[len]) << 18;
-  *c |= uint32_t(s[1] & 0x3f) << 12;
-  *c |= uint32_t(s[2] & 0x3f) << 6;
-  *c |= uint32_t(s[3] & 0x3f) << 0;
+  *c = uint32_t(uchar(s[0]) & masks[len]) << 18;
+  *c |= uint32_t(uchar(s[1]) & 0x3f) << 12;
+  *c |= uint32_t(uchar(s[2]) & 0x3f) << 6;
+  *c |= uint32_t(uchar(s[3]) & 0x3f) << 0;
   *c >>= shiftc[len];
 
   // Accumulate the various error conditions.
-  using uchar = unsigned char;
   *e = (*c < mins[len]) << 6;       // non-canonical encoding
   *e |= ((*c >> 11) == 0x1b) << 7;  // surrogate half?
   *e |= (*c > 0x10FFFF) << 8;       // out of range?
@@ -520,7 +706,7 @@ FMT_CONSTEXPR inline auto utf8_decode(const char* s, uint32_t* c, int* e)
   return next;
 }
 
-constexpr uint32_t invalid_code_point = ~uint32_t();
+constexpr FMT_INLINE_VARIABLE uint32_t invalid_code_point = ~uint32_t();
 
 // Invokes f(cp, sv) for every code point cp in s with sv being the string view
 // corresponding to the code point. cp is invalid_code_point on error.
@@ -531,8 +717,8 @@ FMT_CONSTEXPR void for_each_codepoint(string_view s, F f) {
     auto error = 0;
     auto end = utf8_decode(buf_ptr, &cp, &error);
     bool result = f(error ? invalid_code_point : cp,
-                    string_view(ptr, to_unsigned(end - buf_ptr)));
-    return result ? end : nullptr;
+                    string_view(ptr, error ? 1 : to_unsigned(end - buf_ptr)));
+    return result ? (error ? buf_ptr + 1 : end) : nullptr;
   };
   auto p = s.data();
   const size_t block_size = 4;  // utf8_decode always reads blocks of 4 chars.
@@ -590,13 +776,14 @@ FMT_CONSTEXPR inline size_t compute_width(string_view s) {
       return true;
     }
   };
+  // We could avoid branches by using utf8_decode directly.
   for_each_codepoint(s, count_code_points{&num_code_points});
   return num_code_points;
 }
 
 inline auto compute_width(basic_string_view<char8_type> s) -> size_t {
-  return compute_width(basic_string_view<char>(
-      reinterpret_cast<const char*>(s.data()), s.size()));
+  return compute_width(
+      string_view(reinterpret_cast<const char*>(s.data()), s.size()));
 }
 
 template <typename Char>
@@ -606,9 +793,8 @@ inline auto code_point_index(basic_string_view<Char> s, size_t n) -> size_t {
 }
 
 // Calculates the index of the nth code point in a UTF-8 string.
-inline auto code_point_index(basic_string_view<char8_type> s, size_t n)
-    -> size_t {
-  const char8_type* data = s.data();
+inline auto code_point_index(string_view s, size_t n) -> size_t {
+  const char* data = s.data();
   size_t num_code_points = 0;
   for (size_t i = 0, size = s.size(); i != size; ++i) {
     if ((data[i] & 0xc0) != 0x80 && ++num_code_points > n) return i;
@@ -616,11 +802,73 @@ inline auto code_point_index(basic_string_view<char8_type> s, size_t n)
   return s.size();
 }
 
+inline auto code_point_index(basic_string_view<char8_type> s, size_t n)
+    -> size_t {
+  return code_point_index(
+      string_view(reinterpret_cast<const char*>(s.data()), s.size()), n);
+}
+
+template <typename T> struct is_integral : std::is_integral<T> {};
+template <> struct is_integral<int128_opt> : std::true_type {};
+template <> struct is_integral<uint128_t> : std::true_type {};
+
+template <typename T>
+using is_signed =
+    std::integral_constant<bool, std::numeric_limits<T>::is_signed ||
+                                     std::is_same<T, int128_opt>::value>;
+
+template <typename T>
+using is_integer =
+    bool_constant<is_integral<T>::value && !std::is_same<T, bool>::value &&
+                  !std::is_same<T, char>::value &&
+                  !std::is_same<T, wchar_t>::value>;
+
+#ifndef FMT_USE_FLOAT
+#  define FMT_USE_FLOAT 1
+#endif
+#ifndef FMT_USE_DOUBLE
+#  define FMT_USE_DOUBLE 1
+#endif
+#ifndef FMT_USE_LONG_DOUBLE
+#  define FMT_USE_LONG_DOUBLE 1
+#endif
+
+#ifndef FMT_USE_FLOAT128
+#  ifdef __clang__
+// Clang emulates GCC, so it has to appear early.
+#    if FMT_HAS_INCLUDE(<quadmath.h>)
+#      define FMT_USE_FLOAT128 1
+#    endif
+#  elif defined(__GNUC__)
+// GNU C++:
+#    if defined(_GLIBCXX_USE_FLOAT128) && !defined(__STRICT_ANSI__)
+#      define FMT_USE_FLOAT128 1
+#    endif
+#  endif
+#  ifndef FMT_USE_FLOAT128
+#    define FMT_USE_FLOAT128 0
+#  endif
+#endif
+
+#if FMT_USE_FLOAT128
+using float128 = __float128;
+#else
+using float128 = void;
+#endif
+template <typename T> using is_float128 = std::is_same<T, float128>;
+
+template <typename T>
+using is_floating_point =
+    bool_constant<std::is_floating_point<T>::value || is_float128<T>::value>;
+
 template <typename T, bool = std::is_floating_point<T>::value>
 struct is_fast_float : bool_constant<std::numeric_limits<T>::is_iec559 &&
                                      sizeof(T) <= sizeof(double)> {};
 template <typename T> struct is_fast_float<T, false> : std::false_type {};
 
+template <typename T>
+using is_double_double = bool_constant<std::numeric_limits<T>::digits == 106>;
+
 #ifndef FMT_USE_FULL_CACHE_DRAGONBOX
 #  define FMT_USE_FULL_CACHE_DRAGONBOX 0
 #endif
@@ -645,7 +893,7 @@ template <typename T>
 struct is_locale<T, void_t<decltype(T::classic())>> : std::true_type {};
 }  // namespace detail
 
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 // The number of characters to store in the basic_memory_buffer object itself
 // to avoid dynamic memory allocation.
@@ -688,7 +936,27 @@ class basic_memory_buffer final : public detail::buffer<T> {
   }
 
  protected:
-  FMT_CONSTEXPR20 void grow(size_t size) override;
+  FMT_CONSTEXPR20 void grow(size_t size) override {
+    detail::abort_fuzzing_if(size > 5000);
+    const size_t max_size = std::allocator_traits<Allocator>::max_size(alloc_);
+    size_t old_capacity = this->capacity();
+    size_t new_capacity = old_capacity + old_capacity / 2;
+    if (size > new_capacity)
+      new_capacity = size;
+    else if (new_capacity > max_size)
+      new_capacity = size > max_size ? size : max_size;
+    T* old_data = this->data();
+    T* new_data =
+        std::allocator_traits<Allocator>::allocate(alloc_, new_capacity);
+    // The following code doesn't throw, so the raw pointer above doesn't leak.
+    std::uninitialized_copy(old_data, old_data + this->size(),
+                            detail::make_checked(new_data, new_capacity));
+    this->set(new_data, new_capacity);
+    // deallocate must not throw according to the standard, but even if it does,
+    // the buffer already uses the new storage and will deallocate it in
+    // destructor.
+    if (old_data != store_) alloc_.deallocate(old_data, old_capacity);
+  }
 
  public:
   using value_type = T;
@@ -698,9 +966,7 @@ class basic_memory_buffer final : public detail::buffer<T> {
       const Allocator& alloc = Allocator())
       : alloc_(alloc) {
     this->set(store_, SIZE);
-    if (detail::is_constant_evaluated()) {
-      detail::fill_n(store_, SIZE, T{});
-    }
+    if (detail::is_constant_evaluated()) detail::fill_n(store_, SIZE, T());
   }
   FMT_CONSTEXPR20 ~basic_memory_buffer() { deallocate(); }
 
@@ -712,18 +978,14 @@ class basic_memory_buffer final : public detail::buffer<T> {
     size_t size = other.size(), capacity = other.capacity();
     if (data == other.store_) {
       this->set(store_, capacity);
-      if (detail::is_constant_evaluated()) {
-        detail::copy_str<T>(other.store_, other.store_ + size,
-                            detail::make_checked(store_, capacity));
-      } else {
-        std::uninitialized_copy(other.store_, other.store_ + size,
-                                detail::make_checked(store_, capacity));
-      }
+      detail::copy_str<T>(other.store_, other.store_ + size,
+                          detail::make_checked(store_, capacity));
     } else {
       this->set(data, capacity);
       // Set pointer to the inline array so that delete is not called
       // when deallocating.
       other.set(other.store_, 0);
+      other.clear();
     }
     this->resize(size);
   }
@@ -735,8 +997,7 @@ class basic_memory_buffer final : public detail::buffer<T> {
     of the other object to it.
     \endrst
    */
-  FMT_CONSTEXPR20 basic_memory_buffer(basic_memory_buffer&& other)
-      FMT_NOEXCEPT {
+  FMT_CONSTEXPR20 basic_memory_buffer(basic_memory_buffer&& other) noexcept {
     move(other);
   }
 
@@ -745,8 +1006,7 @@ class basic_memory_buffer final : public detail::buffer<T> {
     Moves the content of the other ``basic_memory_buffer`` object to this one.
     \endrst
    */
-  auto operator=(basic_memory_buffer&& other) FMT_NOEXCEPT
-      -> basic_memory_buffer& {
+  auto operator=(basic_memory_buffer&& other) noexcept -> basic_memory_buffer& {
     FMT_ASSERT(this != &other, "");
     deallocate();
     move(other);
@@ -773,86 +1033,38 @@ class basic_memory_buffer final : public detail::buffer<T> {
   }
 };
 
-template <typename T, size_t SIZE, typename Allocator>
-FMT_CONSTEXPR20 void basic_memory_buffer<T, SIZE, Allocator>::grow(
-    size_t size) {
-#ifdef FMT_FUZZ
-  if (size > 5000) throw std::runtime_error("fuzz mode - won't grow that much");
-#endif
-  const size_t max_size = std::allocator_traits<Allocator>::max_size(alloc_);
-  size_t old_capacity = this->capacity();
-  size_t new_capacity = old_capacity + old_capacity / 2;
-  if (size > new_capacity)
-    new_capacity = size;
-  else if (new_capacity > max_size)
-    new_capacity = size > max_size ? size : max_size;
-  T* old_data = this->data();
-  T* new_data =
-      std::allocator_traits<Allocator>::allocate(alloc_, new_capacity);
-  // The following code doesn't throw, so the raw pointer above doesn't leak.
-  std::uninitialized_copy(old_data, old_data + this->size(),
-                          detail::make_checked(new_data, new_capacity));
-  this->set(new_data, new_capacity);
-  // deallocate must not throw according to the standard, but even if it does,
-  // the buffer already uses the new storage and will deallocate it in
-  // destructor.
-  if (old_data != store_) alloc_.deallocate(old_data, old_capacity);
-}
-
 using memory_buffer = basic_memory_buffer<char>;
 
 template <typename T, size_t SIZE, typename Allocator>
 struct is_contiguous<basic_memory_buffer<T, SIZE, Allocator>> : std::true_type {
 };
 
+FMT_END_EXPORT
 namespace detail {
+FMT_API bool write_console(std::FILE* f, string_view text);
 FMT_API void print(std::FILE*, string_view);
-}
+}  // namespace detail
+FMT_BEGIN_EXPORT
 
-/** A formatting error such as invalid format string. */
-FMT_CLASS_API
+// Suppress a misleading warning in older versions of clang.
+#if FMT_CLANG_VERSION
+#  pragma clang diagnostic ignored "-Wweak-vtables"
+#endif
+
+/** An error reported from a formatting function. */
 class FMT_API format_error : public std::runtime_error {
  public:
-  explicit format_error(const char* message) : std::runtime_error(message) {}
-  explicit format_error(const std::string& message)
-      : std::runtime_error(message) {}
-  format_error(const format_error&) = default;
-  format_error& operator=(const format_error&) = default;
-  format_error(format_error&&) = default;
-  format_error& operator=(format_error&&) = default;
-  ~format_error() FMT_NOEXCEPT override FMT_MSC_DEFAULT;
+  using std::runtime_error::runtime_error;
 };
 
-/**
-  \rst
-  Constructs a `~fmt::format_arg_store` object that contains references
-  to arguments and can be implicitly converted to `~fmt::format_args`.
-  If ``fmt`` is a compile-time string then `make_args_checked` checks
-  its validity at compile time.
-  \endrst
- */
-template <typename... Args, typename S, typename Char = char_t<S>>
-FMT_INLINE auto make_args_checked(const S& fmt,
-                                  const remove_reference_t<Args>&... args)
-    -> format_arg_store<buffer_context<Char>, remove_reference_t<Args>...> {
-  static_assert(
-      detail::count<(
-              std::is_base_of<detail::view, remove_reference_t<Args>>::value &&
-              std::is_reference<Args>::value)...>() == 0,
-      "passing views as lvalues is disallowed");
-  detail::check_format_string<Args...>(fmt);
-  return {args...};
-}
-
-// compile-time support
 namespace detail_exported {
-#if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#if FMT_USE_NONTYPE_TEMPLATE_ARGS
 template <typename Char, size_t N> struct fixed_string {
   constexpr fixed_string(const Char (&str)[N]) {
     detail::copy_str<Char, const Char*, Char*>(static_cast<const Char*>(str),
                                                str + N, data);
   }
-  Char data[N]{};
+  Char data[N] = {};
 };
 #endif
 
@@ -871,33 +1083,70 @@ constexpr auto compile_string_to_view(detail::std_string_view<Char> s)
 }
 }  // namespace detail_exported
 
-FMT_BEGIN_DETAIL_NAMESPACE
+class loc_value {
+ private:
+  basic_format_arg<format_context> value_;
 
-template <typename T> struct is_integral : std::is_integral<T> {};
-template <> struct is_integral<int128_t> : std::true_type {};
-template <> struct is_integral<uint128_t> : std::true_type {};
+ public:
+  template <typename T, FMT_ENABLE_IF(!detail::is_float128<T>::value)>
+  loc_value(T value) : value_(detail::make_arg<format_context>(value)) {}
 
-template <typename T>
-using is_signed =
-    std::integral_constant<bool, std::numeric_limits<T>::is_signed ||
-                                     std::is_same<T, int128_t>::value>;
+  template <typename T, FMT_ENABLE_IF(detail::is_float128<T>::value)>
+  loc_value(T) {}
+
+  template <typename Visitor> auto visit(Visitor&& vis) -> decltype(vis(0)) {
+    return visit_format_arg(vis, value_);
+  }
+};
+
+// A locale facet that formats values in UTF-8.
+// It is parameterized on the locale to avoid the heavy <locale> include.
+template <typename Locale> class format_facet : public Locale::facet {
+ private:
+  std::string separator_;
+  std::string grouping_;
+  std::string decimal_point_;
+
+ protected:
+  virtual auto do_put(appender out, loc_value val,
+                      const format_specs<>& specs) const -> bool;
+
+ public:
+  static FMT_API typename Locale::id id;
+
+  explicit format_facet(Locale& loc);
+  explicit format_facet(string_view sep = "",
+                        std::initializer_list<unsigned char> g = {3},
+                        std::string decimal_point = ".")
+      : separator_(sep.data(), sep.size()),
+        grouping_(g.begin(), g.end()),
+        decimal_point_(decimal_point) {}
+
+  auto put(appender out, loc_value val, const format_specs<>& specs) const
+      -> bool {
+    return do_put(out, val, specs);
+  }
+};
+
+FMT_BEGIN_DETAIL_NAMESPACE
 
 // Returns true if value is negative, false otherwise.
 // Same as `value < 0` but doesn't produce warnings if T is an unsigned type.
 template <typename T, FMT_ENABLE_IF(is_signed<T>::value)>
-FMT_CONSTEXPR auto is_negative(T value) -> bool {
+constexpr auto is_negative(T value) -> bool {
   return value < 0;
 }
 template <typename T, FMT_ENABLE_IF(!is_signed<T>::value)>
-FMT_CONSTEXPR auto is_negative(T) -> bool {
+constexpr auto is_negative(T) -> bool {
   return false;
 }
 
-template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-FMT_CONSTEXPR auto is_supported_floating_point(T) -> uint16_t {
-  return (std::is_same<T, float>::value && FMT_USE_FLOAT) ||
-         (std::is_same<T, double>::value && FMT_USE_DOUBLE) ||
-         (std::is_same<T, long double>::value && FMT_USE_LONG_DOUBLE);
+template <typename T>
+FMT_CONSTEXPR auto is_supported_floating_point(T) -> bool {
+  if (std::is_same<T, float>()) return FMT_USE_FLOAT;
+  if (std::is_same<T, double>()) return FMT_USE_DOUBLE;
+  if (std::is_same<T, long double>()) return FMT_USE_LONG_DOUBLE;
+  return true;
 }
 
 // Smallest of uint32_t, uint64_t, uint128_t that is large enough to
@@ -948,7 +1197,7 @@ template <typename T> FMT_CONSTEXPR auto count_digits_fallback(T n) -> int {
   }
 }
 #if FMT_USE_INT128
-FMT_CONSTEXPR inline auto count_digits(uint128_t n) -> int {
+FMT_CONSTEXPR inline auto count_digits(uint128_opt n) -> int {
   return count_digits_fallback(n);
 }
 #endif
@@ -989,7 +1238,7 @@ FMT_CONSTEXPR20 inline auto count_digits(uint64_t n) -> int {
 template <int BITS, typename UInt>
 FMT_CONSTEXPR auto count_digits(UInt n) -> int {
 #ifdef FMT_BUILTIN_CLZ
-  if (num_bits<UInt>() == 32)
+  if (!is_constant_evaluated() && num_bits<UInt>() == 32)
     return (FMT_BUILTIN_CLZ(static_cast<uint32_t>(n) | 1) ^ 31) / BITS + 1;
 #endif
   // Lambda avoids unreachable code warnings from NVHPC.
@@ -1002,8 +1251,6 @@ FMT_CONSTEXPR auto count_digits(UInt n) -> int {
   }(n);
 }
 
-template <> auto count_digits<4>(detail::fallback_uintptr n) -> int;
-
 #ifdef FMT_BUILTIN_CLZ
 // It is a separate function rather than a part of count_digits to workaround
 // the lack of static constexpr in constexpr functions.
@@ -1039,15 +1286,11 @@ FMT_CONSTEXPR20 inline auto count_digits(uint32_t n) -> int {
   return count_digits_fallback(n);
 }
 
-template <typename Int> constexpr auto digits10() FMT_NOEXCEPT -> int {
+template <typename Int> constexpr auto digits10() noexcept -> int {
   return std::numeric_limits<Int>::digits10;
 }
-template <> constexpr auto digits10<int128_t>() FMT_NOEXCEPT -> int {
-  return 38;
-}
-template <> constexpr auto digits10<uint128_t>() FMT_NOEXCEPT -> int {
-  return 38;
-}
+template <> constexpr auto digits10<int128_opt>() noexcept -> int { return 38; }
+template <> constexpr auto digits10<uint128_t>() noexcept -> int { return 38; }
 
 template <typename Char> struct thousands_sep_result {
   std::string grouping;
@@ -1127,10 +1370,10 @@ FMT_CONSTEXPR20 auto format_decimal(Char* out, UInt value, int size)
 
 template <typename Char, typename UInt, typename Iterator,
           FMT_ENABLE_IF(!std::is_pointer<remove_cvref_t<Iterator>>::value)>
-inline auto format_decimal(Iterator out, UInt value, int size)
+FMT_CONSTEXPR inline auto format_decimal(Iterator out, UInt value, int size)
     -> format_decimal_result<Iterator> {
   // Buffer is large enough to hold all digits (digits10 + 1).
-  Char buffer[digits10<UInt>() + 1];
+  Char buffer[digits10<UInt>() + 1] = {};
   auto end = format_decimal(buffer, value, size).end;
   return {out, detail::copy_str_noinline<Char>(buffer, end, out)};
 }
@@ -1142,35 +1385,13 @@ FMT_CONSTEXPR auto format_uint(Char* buffer, UInt value, int num_digits,
   Char* end = buffer;
   do {
     const char* digits = upper ? "0123456789ABCDEF" : "0123456789abcdef";
-    unsigned digit = (value & ((1 << BASE_BITS) - 1));
+    unsigned digit = static_cast<unsigned>(value & ((1 << BASE_BITS) - 1));
     *--buffer = static_cast<Char>(BASE_BITS < 4 ? static_cast<char>('0' + digit)
                                                 : digits[digit]);
   } while ((value >>= BASE_BITS) != 0);
   return end;
 }
 
-template <unsigned BASE_BITS, typename Char>
-auto format_uint(Char* buffer, detail::fallback_uintptr n, int num_digits,
-                 bool = false) -> Char* {
-  auto char_digits = std::numeric_limits<unsigned char>::digits / 4;
-  int start = (num_digits + char_digits - 1) / char_digits - 1;
-  if (int start_digits = num_digits % char_digits) {
-    unsigned value = n.value[start--];
-    buffer = format_uint<BASE_BITS>(buffer, value, start_digits);
-  }
-  for (; start >= 0; --start) {
-    unsigned value = n.value[start];
-    buffer += char_digits;
-    auto p = buffer;
-    for (int i = 0; i < char_digits; ++i) {
-      unsigned digit = (value & ((1 << BASE_BITS) - 1));
-      *--p = static_cast<Char>("0123456789abcdef"[digit]);
-      value >>= BASE_BITS;
-    }
-  }
-  return buffer;
-}
-
 template <unsigned BASE_BITS, typename Char, typename It, typename UInt>
 inline auto format_uint(It out, UInt value, int num_digits, bool upper = false)
     -> It {
@@ -1197,61 +1418,174 @@ class utf8_to_utf16 {
   auto str() const -> std::wstring { return {&buffer_[0], size()}; }
 };
 
+// A converter from UTF-16/UTF-32 (host endian) to UTF-8.
+template <typename WChar, typename Buffer = memory_buffer>
+class unicode_to_utf8 {
+ private:
+  Buffer buffer_;
+
+ public:
+  unicode_to_utf8() {}
+  explicit unicode_to_utf8(basic_string_view<WChar> s) {
+    static_assert(sizeof(WChar) == 2 || sizeof(WChar) == 4,
+                  "Expect utf16 or utf32");
+
+    if (!convert(s))
+      FMT_THROW(std::runtime_error(sizeof(WChar) == 2 ? "invalid utf16"
+                                                      : "invalid utf32"));
+  }
+  operator string_view() const { return string_view(&buffer_[0], size()); }
+  size_t size() const { return buffer_.size() - 1; }
+  const char* c_str() const { return &buffer_[0]; }
+  std::string str() const { return std::string(&buffer_[0], size()); }
+
+  // Performs conversion returning a bool instead of throwing exception on
+  // conversion error. This method may still throw in case of memory allocation
+  // error.
+  bool convert(basic_string_view<WChar> s) {
+    if (!convert(buffer_, s)) return false;
+    buffer_.push_back(0);
+    return true;
+  }
+  static bool convert(Buffer& buf, basic_string_view<WChar> s) {
+    for (auto p = s.begin(); p != s.end(); ++p) {
+      uint32_t c = static_cast<uint32_t>(*p);
+      if (sizeof(WChar) == 2 && c >= 0xd800 && c <= 0xdfff) {
+        // surrogate pair
+        ++p;
+        if (p == s.end() || (c & 0xfc00) != 0xd800 || (*p & 0xfc00) != 0xdc00) {
+          return false;
+        }
+        c = (c << 10) + static_cast<uint32_t>(*p) - 0x35fdc00;
+      }
+      if (c < 0x80) {
+        buf.push_back(static_cast<char>(c));
+      } else if (c < 0x800) {
+        buf.push_back(static_cast<char>(0xc0 | (c >> 6)));
+        buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
+      } else if ((c >= 0x800 && c <= 0xd7ff) || (c >= 0xe000 && c <= 0xffff)) {
+        buf.push_back(static_cast<char>(0xe0 | (c >> 12)));
+        buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
+        buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
+      } else if (c >= 0x10000 && c <= 0x10ffff) {
+        buf.push_back(static_cast<char>(0xf0 | (c >> 18)));
+        buf.push_back(static_cast<char>(0x80 | ((c & 0x3ffff) >> 12)));
+        buf.push_back(static_cast<char>(0x80 | ((c & 0xfff) >> 6)));
+        buf.push_back(static_cast<char>(0x80 | (c & 0x3f)));
+      } else {
+        return false;
+      }
+    }
+    return true;
+  }
+};
+
+// Computes 128-bit result of multiplication of two 64-bit unsigned integers.
+inline uint128_fallback umul128(uint64_t x, uint64_t y) noexcept {
+#if FMT_USE_INT128
+  auto p = static_cast<uint128_opt>(x) * static_cast<uint128_opt>(y);
+  return {static_cast<uint64_t>(p >> 64), static_cast<uint64_t>(p)};
+#elif defined(_MSC_VER) && defined(_M_X64)
+  auto result = uint128_fallback();
+  result.lo_ = _umul128(x, y, &result.hi_);
+  return result;
+#else
+  const uint64_t mask = static_cast<uint64_t>(max_value<uint32_t>());
+
+  uint64_t a = x >> 32;
+  uint64_t b = x & mask;
+  uint64_t c = y >> 32;
+  uint64_t d = y & mask;
+
+  uint64_t ac = a * c;
+  uint64_t bc = b * c;
+  uint64_t ad = a * d;
+  uint64_t bd = b * d;
+
+  uint64_t intermediate = (bd >> 32) + (ad & mask) + (bc & mask);
+
+  return {ac + (intermediate >> 32) + (ad >> 32) + (bc >> 32),
+          (intermediate << 32) + (bd & mask)};
+#endif
+}
+
 namespace dragonbox {
+// Computes floor(log10(pow(2, e))) for e in [-2620, 2620] using the method from
+// https://fmt.dev/papers/Dragonbox.pdf#page=28, section 6.1.
+inline int floor_log10_pow2(int e) noexcept {
+  FMT_ASSERT(e <= 2620 && e >= -2620, "too large exponent");
+  static_assert((-1 >> 1) == -1, "right shift is not arithmetic");
+  return (e * 315653) >> 20;
+}
+
+inline int floor_log2_pow10(int e) noexcept {
+  FMT_ASSERT(e <= 1233 && e >= -1233, "too large exponent");
+  return (e * 1741647) >> 19;
+}
+
+// Computes upper 64 bits of multiplication of two 64-bit unsigned integers.
+inline uint64_t umul128_upper64(uint64_t x, uint64_t y) noexcept {
+#if FMT_USE_INT128
+  auto p = static_cast<uint128_opt>(x) * static_cast<uint128_opt>(y);
+  return static_cast<uint64_t>(p >> 64);
+#elif defined(_MSC_VER) && defined(_M_X64)
+  return __umulh(x, y);
+#else
+  return umul128(x, y).high();
+#endif
+}
+
+// Computes upper 128 bits of multiplication of a 64-bit unsigned integer and a
+// 128-bit unsigned integer.
+inline uint128_fallback umul192_upper128(uint64_t x,
+                                         uint128_fallback y) noexcept {
+  uint128_fallback r = umul128(x, y.high());
+  r += umul128_upper64(x, y.low());
+  return r;
+}
+
+FMT_API uint128_fallback get_cached_power(int k) noexcept;
 
 // Type-specific information that Dragonbox uses.
-template <class T> struct float_info;
+template <typename T, typename Enable = void> struct float_info;
 
 template <> struct float_info<float> {
   using carrier_uint = uint32_t;
-  static const int significand_bits = 23;
   static const int exponent_bits = 8;
-  static const int min_exponent = -126;
-  static const int max_exponent = 127;
-  static const int exponent_bias = -127;
-  static const int decimal_digits = 9;
   static const int kappa = 1;
   static const int big_divisor = 100;
   static const int small_divisor = 10;
   static const int min_k = -31;
   static const int max_k = 46;
-  static const int cache_bits = 64;
-  static const int divisibility_check_by_5_threshold = 39;
-  static const int case_fc_pm_half_lower_threshold = -1;
-  static const int case_fc_pm_half_upper_threshold = 6;
-  static const int case_fc_lower_threshold = -2;
-  static const int case_fc_upper_threshold = 6;
-  static const int case_shorter_interval_left_endpoint_lower_threshold = 2;
-  static const int case_shorter_interval_left_endpoint_upper_threshold = 3;
   static const int shorter_interval_tie_lower_threshold = -35;
   static const int shorter_interval_tie_upper_threshold = -35;
-  static const int max_trailing_zeros = 7;
 };
 
 template <> struct float_info<double> {
   using carrier_uint = uint64_t;
-  static const int significand_bits = 52;
   static const int exponent_bits = 11;
-  static const int min_exponent = -1022;
-  static const int max_exponent = 1023;
-  static const int exponent_bias = -1023;
-  static const int decimal_digits = 17;
   static const int kappa = 2;
   static const int big_divisor = 1000;
   static const int small_divisor = 100;
   static const int min_k = -292;
-  static const int max_k = 326;
-  static const int cache_bits = 128;
-  static const int divisibility_check_by_5_threshold = 86;
-  static const int case_fc_pm_half_lower_threshold = -2;
-  static const int case_fc_pm_half_upper_threshold = 9;
-  static const int case_fc_lower_threshold = -4;
-  static const int case_fc_upper_threshold = 9;
-  static const int case_shorter_interval_left_endpoint_lower_threshold = 2;
-  static const int case_shorter_interval_left_endpoint_upper_threshold = 3;
+  static const int max_k = 341;
   static const int shorter_interval_tie_lower_threshold = -77;
   static const int shorter_interval_tie_upper_threshold = -77;
-  static const int max_trailing_zeros = 16;
+};
+
+// An 80- or 128-bit floating point number.
+template <typename T>
+struct float_info<T, enable_if_t<std::numeric_limits<T>::digits == 64 ||
+                                 std::numeric_limits<T>::digits == 113 ||
+                                 is_float128<T>::value>> {
+  using carrier_uint = detail::uint128_t;
+  static const int exponent_bits = 15;
+};
+
+// A double-double floating point number.
+template <typename T>
+struct float_info<T, enable_if_t<is_double_double<T>::value>> {
+  using carrier_uint = detail::uint128_t;
 };
 
 template <typename T> struct decimal_fp {
@@ -1260,16 +1594,35 @@ template <typename T> struct decimal_fp {
   int exponent;
 };
 
-template <typename T>
-FMT_API auto to_decimal(T x) FMT_NOEXCEPT -> decimal_fp<T>;
+template <typename T> FMT_API auto to_decimal(T x) noexcept -> decimal_fp<T>;
 }  // namespace dragonbox
 
-template <typename T>
+// Returns true iff Float has the implicit bit which is not stored.
+template <typename Float> constexpr bool has_implicit_bit() {
+  // An 80-bit FP number has a 64-bit significand an no implicit bit.
+  return std::numeric_limits<Float>::digits != 64;
+}
+
+// Returns the number of significand bits stored in Float. The implicit bit is
+// not counted since it is not stored.
+template <typename Float> constexpr int num_significand_bits() {
+  // std::numeric_limits may not support __float128.
+  return is_float128<Float>() ? 112
+                              : (std::numeric_limits<Float>::digits -
+                                 (has_implicit_bit<Float>() ? 1 : 0));
+}
+
+template <typename Float>
 constexpr auto exponent_mask() ->
-    typename dragonbox::float_info<T>::carrier_uint {
-  using uint = typename dragonbox::float_info<T>::carrier_uint;
-  return ((uint(1) << dragonbox::float_info<T>::exponent_bits) - 1)
-         << dragonbox::float_info<T>::significand_bits;
+    typename dragonbox::float_info<Float>::carrier_uint {
+  using float_uint = typename dragonbox::float_info<Float>::carrier_uint;
+  return ((float_uint(1) << dragonbox::float_info<Float>::exponent_bits) - 1)
+         << num_significand_bits<Float>();
+}
+template <typename Float> constexpr auto exponent_bias() -> int {
+  // std::numeric_limits may not support __float128.
+  return is_float128<Float>() ? 16383
+                              : std::numeric_limits<Float>::max_exponent - 1;
 }
 
 // Writes the exponent exp in the form "[+-]d{2,3}" to buffer.
@@ -1294,21 +1647,213 @@ FMT_CONSTEXPR auto write_exponent(int exp, It it) -> It {
   return it;
 }
 
-template <typename T>
-FMT_HEADER_ONLY_CONSTEXPR20 auto format_float(T value, int precision,
-                                              float_specs specs,
-                                              buffer<char>& buf) -> int;
+// A floating-point number f * pow(2, e) where F is an unsigned type.
+template <typename F> struct basic_fp {
+  F f;
+  int e;
+
+  static constexpr const int num_significand_bits =
+      static_cast<int>(sizeof(F) * num_bits<unsigned char>());
+
+  constexpr basic_fp() : f(0), e(0) {}
+  constexpr basic_fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
+
+  // Constructs fp from an IEEE754 floating-point number.
+  template <typename Float> FMT_CONSTEXPR basic_fp(Float n) { assign(n); }
+
+  // Assigns n to this and return true iff predecessor is closer than successor.
+  template <typename Float, FMT_ENABLE_IF(!is_double_double<Float>::value)>
+  FMT_CONSTEXPR auto assign(Float n) -> bool {
+    static_assert(std::numeric_limits<Float>::digits <= 113, "unsupported FP");
+    // Assume Float is in the format [sign][exponent][significand].
+    using carrier_uint = typename dragonbox::float_info<Float>::carrier_uint;
+    const auto num_float_significand_bits =
+        detail::num_significand_bits<Float>();
+    const auto implicit_bit = carrier_uint(1) << num_float_significand_bits;
+    const auto significand_mask = implicit_bit - 1;
+    auto u = bit_cast<carrier_uint>(n);
+    f = static_cast<F>(u & significand_mask);
+    auto biased_e = static_cast<int>((u & exponent_mask<Float>()) >>
+                                     num_float_significand_bits);
+    // The predecessor is closer if n is a normalized power of 2 (f == 0)
+    // other than the smallest normalized number (biased_e > 1).
+    auto is_predecessor_closer = f == 0 && biased_e > 1;
+    if (biased_e == 0)
+      biased_e = 1;  // Subnormals use biased exponent 1 (min exponent).
+    else if (has_implicit_bit<Float>())
+      f += static_cast<F>(implicit_bit);
+    e = biased_e - exponent_bias<Float>() - num_float_significand_bits;
+    if (!has_implicit_bit<Float>()) ++e;
+    return is_predecessor_closer;
+  }
 
-// Formats a floating-point number with snprintf.
-template <typename T>
-auto snprintf_float(T value, int precision, float_specs specs,
-                    buffer<char>& buf) -> int;
+  template <typename Float, FMT_ENABLE_IF(is_double_double<Float>::value)>
+  FMT_CONSTEXPR auto assign(Float n) -> bool {
+    static_assert(std::numeric_limits<double>::is_iec559, "unsupported FP");
+    return assign(static_cast<double>(n));
+  }
+};
 
-template <typename T> constexpr auto promote_float(T value) -> T {
+using fp = basic_fp<unsigned long long>;
+
+// Normalizes the value converted from double and multiplied by (1 << SHIFT).
+template <int SHIFT = 0, typename F>
+FMT_CONSTEXPR basic_fp<F> normalize(basic_fp<F> value) {
+  // Handle subnormals.
+  const auto implicit_bit = F(1) << num_significand_bits<double>();
+  const auto shifted_implicit_bit = implicit_bit << SHIFT;
+  while ((value.f & shifted_implicit_bit) == 0) {
+    value.f <<= 1;
+    --value.e;
+  }
+  // Subtract 1 to account for hidden bit.
+  const auto offset = basic_fp<F>::num_significand_bits -
+                      num_significand_bits<double>() - SHIFT - 1;
+  value.f <<= offset;
+  value.e -= offset;
   return value;
 }
-constexpr auto promote_float(float value) -> double {
-  return static_cast<double>(value);
+
+// Computes lhs * rhs / pow(2, 64) rounded to nearest with half-up tie breaking.
+FMT_CONSTEXPR inline uint64_t multiply(uint64_t lhs, uint64_t rhs) {
+#if FMT_USE_INT128
+  auto product = static_cast<__uint128_t>(lhs) * rhs;
+  auto f = static_cast<uint64_t>(product >> 64);
+  return (static_cast<uint64_t>(product) & (1ULL << 63)) != 0 ? f + 1 : f;
+#else
+  // Multiply 32-bit parts of significands.
+  uint64_t mask = (1ULL << 32) - 1;
+  uint64_t a = lhs >> 32, b = lhs & mask;
+  uint64_t c = rhs >> 32, d = rhs & mask;
+  uint64_t ac = a * c, bc = b * c, ad = a * d, bd = b * d;
+  // Compute mid 64-bit of result and round.
+  uint64_t mid = (bd >> 32) + (ad & mask) + (bc & mask) + (1U << 31);
+  return ac + (ad >> 32) + (bc >> 32) + (mid >> 32);
+#endif
+}
+
+FMT_CONSTEXPR inline fp operator*(fp x, fp y) {
+  return {multiply(x.f, y.f), x.e + y.e + 64};
+}
+
+template <typename T = void> struct basic_data {
+  // Normalized 64-bit significands of pow(10, k), for k = -348, -340, ..., 340.
+  // These are generated by support/compute-powers.py.
+  static constexpr uint64_t pow10_significands[87] = {
+      0xfa8fd5a0081c0288, 0xbaaee17fa23ebf76, 0x8b16fb203055ac76,
+      0xcf42894a5dce35ea, 0x9a6bb0aa55653b2d, 0xe61acf033d1a45df,
+      0xab70fe17c79ac6ca, 0xff77b1fcbebcdc4f, 0xbe5691ef416bd60c,
+      0x8dd01fad907ffc3c, 0xd3515c2831559a83, 0x9d71ac8fada6c9b5,
+      0xea9c227723ee8bcb, 0xaecc49914078536d, 0x823c12795db6ce57,
+      0xc21094364dfb5637, 0x9096ea6f3848984f, 0xd77485cb25823ac7,
+      0xa086cfcd97bf97f4, 0xef340a98172aace5, 0xb23867fb2a35b28e,
+      0x84c8d4dfd2c63f3b, 0xc5dd44271ad3cdba, 0x936b9fcebb25c996,
+      0xdbac6c247d62a584, 0xa3ab66580d5fdaf6, 0xf3e2f893dec3f126,
+      0xb5b5ada8aaff80b8, 0x87625f056c7c4a8b, 0xc9bcff6034c13053,
+      0x964e858c91ba2655, 0xdff9772470297ebd, 0xa6dfbd9fb8e5b88f,
+      0xf8a95fcf88747d94, 0xb94470938fa89bcf, 0x8a08f0f8bf0f156b,
+      0xcdb02555653131b6, 0x993fe2c6d07b7fac, 0xe45c10c42a2b3b06,
+      0xaa242499697392d3, 0xfd87b5f28300ca0e, 0xbce5086492111aeb,
+      0x8cbccc096f5088cc, 0xd1b71758e219652c, 0x9c40000000000000,
+      0xe8d4a51000000000, 0xad78ebc5ac620000, 0x813f3978f8940984,
+      0xc097ce7bc90715b3, 0x8f7e32ce7bea5c70, 0xd5d238a4abe98068,
+      0x9f4f2726179a2245, 0xed63a231d4c4fb27, 0xb0de65388cc8ada8,
+      0x83c7088e1aab65db, 0xc45d1df942711d9a, 0x924d692ca61be758,
+      0xda01ee641a708dea, 0xa26da3999aef774a, 0xf209787bb47d6b85,
+      0xb454e4a179dd1877, 0x865b86925b9bc5c2, 0xc83553c5c8965d3d,
+      0x952ab45cfa97a0b3, 0xde469fbd99a05fe3, 0xa59bc234db398c25,
+      0xf6c69a72a3989f5c, 0xb7dcbf5354e9bece, 0x88fcf317f22241e2,
+      0xcc20ce9bd35c78a5, 0x98165af37b2153df, 0xe2a0b5dc971f303a,
+      0xa8d9d1535ce3b396, 0xfb9b7cd9a4a7443c, 0xbb764c4ca7a44410,
+      0x8bab8eefb6409c1a, 0xd01fef10a657842c, 0x9b10a4e5e9913129,
+      0xe7109bfba19c0c9d, 0xac2820d9623bf429, 0x80444b5e7aa7cf85,
+      0xbf21e44003acdd2d, 0x8e679c2f5e44ff8f, 0xd433179d9c8cb841,
+      0x9e19db92b4e31ba9, 0xeb96bf6ebadf77d9, 0xaf87023b9bf0ee6b,
+  };
+
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wnarrowing"
+#endif
+  // Binary exponents of pow(10, k), for k = -348, -340, ..., 340, corresponding
+  // to significands above.
+  static constexpr int16_t pow10_exponents[87] = {
+      -1220, -1193, -1166, -1140, -1113, -1087, -1060, -1034, -1007, -980, -954,
+      -927,  -901,  -874,  -847,  -821,  -794,  -768,  -741,  -715,  -688, -661,
+      -635,  -608,  -582,  -555,  -529,  -502,  -475,  -449,  -422,  -396, -369,
+      -343,  -316,  -289,  -263,  -236,  -210,  -183,  -157,  -130,  -103, -77,
+      -50,   -24,   3,     30,    56,    83,    109,   136,   162,   189,  216,
+      242,   269,   295,   322,   348,   375,   402,   428,   455,   481,  508,
+      534,   561,   588,   614,   641,   667,   694,   720,   747,   774,  800,
+      827,   853,   880,   907,   933,   960,   986,   1013,  1039,  1066};
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+#  pragma GCC diagnostic pop
+#endif
+
+  static constexpr uint64_t power_of_10_64[20] = {
+      1, FMT_POWERS_OF_10(1ULL), FMT_POWERS_OF_10(1000000000ULL),
+      10000000000000000000ULL};
+
+  // For checking rounding thresholds.
+  // The kth entry is chosen to be the smallest integer such that the
+  // upper 32-bits of 10^(k+1) times it is strictly bigger than 5 * 10^k.
+  static constexpr uint32_t fractional_part_rounding_thresholds[8] = {
+      2576980378,  // ceil(2^31 + 2^32/10^1)
+      2190433321,  // ceil(2^31 + 2^32/10^2)
+      2151778616,  // ceil(2^31 + 2^32/10^3)
+      2147913145,  // ceil(2^31 + 2^32/10^4)
+      2147526598,  // ceil(2^31 + 2^32/10^5)
+      2147487943,  // ceil(2^31 + 2^32/10^6)
+      2147484078,  // ceil(2^31 + 2^32/10^7)
+      2147483691   // ceil(2^31 + 2^32/10^8)
+  };
+};
+
+#if FMT_CPLUSPLUS < 201703L
+template <typename T> constexpr uint64_t basic_data<T>::pow10_significands[];
+template <typename T> constexpr int16_t basic_data<T>::pow10_exponents[];
+template <typename T> constexpr uint64_t basic_data<T>::power_of_10_64[];
+template <typename T>
+constexpr uint32_t basic_data<T>::fractional_part_rounding_thresholds[];
+#endif
+
+// This is a struct rather than an alias to avoid shadowing warnings in gcc.
+struct data : basic_data<> {};
+
+// Returns a cached power of 10 `c_k = c_k.f * pow(2, c_k.e)` such that its
+// (binary) exponent satisfies `min_exponent <= c_k.e <= min_exponent + 28`.
+FMT_CONSTEXPR inline fp get_cached_power(int min_exponent,
+                                         int& pow10_exponent) {
+  const int shift = 32;
+  // log10(2) = 0x0.4d104d427de7fbcc...
+  const int64_t significand = 0x4d104d427de7fbcc;
+  int index = static_cast<int>(
+      ((min_exponent + fp::num_significand_bits - 1) * (significand >> shift) +
+       ((int64_t(1) << shift) - 1))  // ceil
+      >> 32                          // arithmetic shift
+  );
+  // Decimal exponent of the first (smallest) cached power of 10.
+  const int first_dec_exp = -348;
+  // Difference between 2 consecutive decimal exponents in cached powers of 10.
+  const int dec_exp_step = 8;
+  index = (index - first_dec_exp - 1) / dec_exp_step + 1;
+  pow10_exponent = first_dec_exp + index * dec_exp_step;
+  // Using *(x + index) instead of x[index] avoids an issue with some compilers
+  // using the EDG frontend (e.g. nvhpc/22.3 in C++17 mode).
+  return {*(data::pow10_significands + index),
+          *(data::pow10_exponents + index)};
+}
+
+template <typename T>
+using convert_float_result =
+    conditional_t<std::is_same<T, float>::value ||
+                      std::numeric_limits<T>::digits ==
+                          std::numeric_limits<double>::digits,
+                  double, T>;
+
+template <typename T>
+constexpr auto convert_float(T value) -> convert_float_result<T> {
+  return static_cast<convert_float_result<T>>(value);
 }
 
 template <typename OutputIt, typename Char>
@@ -1327,8 +1872,7 @@ FMT_NOINLINE FMT_CONSTEXPR auto fill(OutputIt it, size_t n,
 // width: output display width in (terminal) column positions.
 template <align::type align = align::left, typename OutputIt, typename Char,
           typename F>
-FMT_CONSTEXPR auto write_padded(OutputIt out,
-                                const basic_format_specs<Char>& specs,
+FMT_CONSTEXPR auto write_padded(OutputIt out, const format_specs<Char>& specs,
                                 size_t size, size_t width, F&& f) -> OutputIt {
   static_assert(align == align::left || align == align::right, "");
   unsigned spec_width = to_unsigned(specs.width);
@@ -1347,15 +1891,14 @@ FMT_CONSTEXPR auto write_padded(OutputIt out,
 
 template <align::type align = align::left, typename OutputIt, typename Char,
           typename F>
-constexpr auto write_padded(OutputIt out, const basic_format_specs<Char>& specs,
+constexpr auto write_padded(OutputIt out, const format_specs<Char>& specs,
                             size_t size, F&& f) -> OutputIt {
   return write_padded<align>(out, specs, size, size, f);
 }
 
 template <align::type align = align::left, typename Char, typename OutputIt>
 FMT_CONSTEXPR auto write_bytes(OutputIt out, string_view bytes,
-                               const basic_format_specs<Char>& specs)
-    -> OutputIt {
+                               const format_specs<Char>& specs) -> OutputIt {
   return write_padded<align>(
       out, specs, bytes.size(), [bytes](reserve_iterator<OutputIt> it) {
         const char* data = bytes.data();
@@ -1364,8 +1907,8 @@ FMT_CONSTEXPR auto write_bytes(OutputIt out, string_view bytes,
 }
 
 template <typename Char, typename OutputIt, typename UIntPtr>
-auto write_ptr(OutputIt out, UIntPtr value,
-               const basic_format_specs<Char>* specs) -> OutputIt {
+auto write_ptr(OutputIt out, UIntPtr value, const format_specs<Char>* specs)
+    -> OutputIt {
   int num_digits = count_digits<4>(value);
   auto size = to_unsigned(num_digits) + size_t(2);
   auto write = [=](reserve_iterator<OutputIt> it) {
@@ -1377,22 +1920,183 @@ auto write_ptr(OutputIt out, UIntPtr value,
                : base_iterator(out, write(reserve(out, size)));
 }
 
+// Returns true iff the code point cp is printable.
+FMT_API auto is_printable(uint32_t cp) -> bool;
+
+inline auto needs_escape(uint32_t cp) -> bool {
+  return cp < 0x20 || cp == 0x7f || cp == '"' || cp == '\\' ||
+         !is_printable(cp);
+}
+
+template <typename Char> struct find_escape_result {
+  const Char* begin;
+  const Char* end;
+  uint32_t cp;
+};
+
+template <typename Char>
+using make_unsigned_char =
+    typename conditional_t<std::is_integral<Char>::value,
+                           std::make_unsigned<Char>,
+                           type_identity<uint32_t>>::type;
+
+template <typename Char>
+auto find_escape(const Char* begin, const Char* end)
+    -> find_escape_result<Char> {
+  for (; begin != end; ++begin) {
+    uint32_t cp = static_cast<make_unsigned_char<Char>>(*begin);
+    if (const_check(sizeof(Char) == 1) && cp >= 0x80) continue;
+    if (needs_escape(cp)) return {begin, begin + 1, cp};
+  }
+  return {begin, nullptr, 0};
+}
+
+inline auto find_escape(const char* begin, const char* end)
+    -> find_escape_result<char> {
+  if (!is_utf8()) return find_escape<char>(begin, end);
+  auto result = find_escape_result<char>{end, nullptr, 0};
+  for_each_codepoint(string_view(begin, to_unsigned(end - begin)),
+                     [&](uint32_t cp, string_view sv) {
+                       if (needs_escape(cp)) {
+                         result = {sv.begin(), sv.end(), cp};
+                         return false;
+                       }
+                       return true;
+                     });
+  return result;
+}
+
+#define FMT_STRING_IMPL(s, base, explicit)                                    \
+  [] {                                                                        \
+    /* Use the hidden visibility as a workaround for a GCC bug (#1973). */    \
+    /* Use a macro-like name to avoid shadowing warnings. */                  \
+    struct FMT_GCC_VISIBILITY_HIDDEN FMT_COMPILE_STRING : base {              \
+      using char_type FMT_MAYBE_UNUSED = fmt::remove_cvref_t<decltype(s[0])>; \
+      FMT_MAYBE_UNUSED FMT_CONSTEXPR explicit                                 \
+      operator fmt::basic_string_view<char_type>() const {                    \
+        return fmt::detail_exported::compile_string_to_view<char_type>(s);    \
+      }                                                                       \
+    };                                                                        \
+    return FMT_COMPILE_STRING();                                              \
+  }()
+
+/**
+  \rst
+  Constructs a compile-time format string from a string literal *s*.
+
+  **Example**::
+
+    // A compile-time error because 'd' is an invalid specifier for strings.
+    std::string s = fmt::format(FMT_STRING("{:d}"), "foo");
+  \endrst
+ */
+#define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::detail::compile_string, )
+
+template <size_t width, typename Char, typename OutputIt>
+auto write_codepoint(OutputIt out, char prefix, uint32_t cp) -> OutputIt {
+  *out++ = static_cast<Char>('\\');
+  *out++ = static_cast<Char>(prefix);
+  Char buf[width];
+  fill_n(buf, width, static_cast<Char>('0'));
+  format_uint<4>(buf, cp, width);
+  return copy_str<Char>(buf, buf + width, out);
+}
+
+template <typename OutputIt, typename Char>
+auto write_escaped_cp(OutputIt out, const find_escape_result<Char>& escape)
+    -> OutputIt {
+  auto c = static_cast<Char>(escape.cp);
+  switch (escape.cp) {
+  case '\n':
+    *out++ = static_cast<Char>('\\');
+    c = static_cast<Char>('n');
+    break;
+  case '\r':
+    *out++ = static_cast<Char>('\\');
+    c = static_cast<Char>('r');
+    break;
+  case '\t':
+    *out++ = static_cast<Char>('\\');
+    c = static_cast<Char>('t');
+    break;
+  case '"':
+    FMT_FALLTHROUGH;
+  case '\'':
+    FMT_FALLTHROUGH;
+  case '\\':
+    *out++ = static_cast<Char>('\\');
+    break;
+  default:
+    if (escape.cp < 0x100) {
+      return write_codepoint<2, Char>(out, 'x', escape.cp);
+    }
+    if (escape.cp < 0x10000) {
+      return write_codepoint<4, Char>(out, 'u', escape.cp);
+    }
+    if (escape.cp < 0x110000) {
+      return write_codepoint<8, Char>(out, 'U', escape.cp);
+    }
+    for (Char escape_char : basic_string_view<Char>(
+             escape.begin, to_unsigned(escape.end - escape.begin))) {
+      out = write_codepoint<2, Char>(out, 'x',
+                                     static_cast<uint32_t>(escape_char) & 0xFF);
+    }
+    return out;
+  }
+  *out++ = c;
+  return out;
+}
+
 template <typename Char, typename OutputIt>
-FMT_CONSTEXPR auto write_char(OutputIt out, Char value,
-                              const basic_format_specs<Char>& specs)
+auto write_escaped_string(OutputIt out, basic_string_view<Char> str)
     -> OutputIt {
+  *out++ = static_cast<Char>('"');
+  auto begin = str.begin(), end = str.end();
+  do {
+    auto escape = find_escape(begin, end);
+    out = copy_str<Char>(begin, escape.begin, out);
+    begin = escape.end;
+    if (!begin) break;
+    out = write_escaped_cp<OutputIt, Char>(out, escape);
+  } while (begin != end);
+  *out++ = static_cast<Char>('"');
+  return out;
+}
+
+template <typename Char, typename OutputIt>
+auto write_escaped_char(OutputIt out, Char v) -> OutputIt {
+  *out++ = static_cast<Char>('\'');
+  if ((needs_escape(static_cast<uint32_t>(v)) && v != static_cast<Char>('"')) ||
+      v == static_cast<Char>('\'')) {
+    out = write_escaped_cp(
+        out, find_escape_result<Char>{&v, &v + 1, static_cast<uint32_t>(v)});
+  } else {
+    *out++ = v;
+  }
+  *out++ = static_cast<Char>('\'');
+  return out;
+}
+
+template <typename Char, typename OutputIt>
+FMT_CONSTEXPR auto write_char(OutputIt out, Char value,
+                              const format_specs<Char>& specs) -> OutputIt {
+  bool is_debug = specs.type == presentation_type::debug;
   return write_padded(out, specs, 1, [=](reserve_iterator<OutputIt> it) {
+    if (is_debug) return write_escaped_char(it, value);
     *it++ = value;
     return it;
   });
 }
 template <typename Char, typename OutputIt>
 FMT_CONSTEXPR auto write(OutputIt out, Char value,
-                         const basic_format_specs<Char>& specs,
-                         locale_ref loc = {}) -> OutputIt {
+                         const format_specs<Char>& specs, locale_ref loc = {})
+    -> OutputIt {
+  // char is formatted as unsigned char for consistency across platforms.
+  using unsigned_type =
+      conditional_t<std::is_same<Char, char>::value, unsigned char, unsigned>;
   return check_char_specs(specs)
              ? write_char(out, value, specs)
-             : write(out, static_cast<int>(value), specs, loc);
+             : write(out, static_cast<unsigned_type>(value), specs, loc);
 }
 
 // Data for write_int that doesn't depend on output iterator type. It is used to
@@ -1402,7 +2106,7 @@ template <typename Char> struct write_int_data {
   size_t padding;
 
   FMT_CONSTEXPR write_int_data(int num_digits, unsigned prefix,
-                               const basic_format_specs<Char>& specs)
+                               const format_specs<Char>& specs)
       : size((prefix >> 24) + to_unsigned(num_digits)), padding(0) {
     if (specs.align == align::numeric) {
       auto width = to_unsigned(specs.width);
@@ -1424,7 +2128,7 @@ template <typename Char> struct write_int_data {
 template <typename OutputIt, typename Char, typename W>
 FMT_CONSTEXPR FMT_INLINE auto write_int(OutputIt out, int num_digits,
                                         unsigned prefix,
-                                        const basic_format_specs<Char>& specs,
+                                        const format_specs<Char>& specs,
                                         W write_digits) -> OutputIt {
   // Slightly faster check for specs.width == 0 && specs.precision == -1.
   if ((specs.width | (specs.precision + 1)) == 0) {
@@ -1447,19 +2151,19 @@ FMT_CONSTEXPR FMT_INLINE auto write_int(OutputIt out, int num_digits,
 
 template <typename Char> class digit_grouping {
  private:
-  thousands_sep_result<Char> sep_;
+  std::string grouping_;
+  std::basic_string<Char> thousands_sep_;
 
   struct next_state {
     std::string::const_iterator group;
     int pos;
   };
-  next_state initial_state() const { return {sep_.grouping.begin(), 0}; }
+  next_state initial_state() const { return {grouping_.begin(), 0}; }
 
   // Returns the next digit group separator position.
   int next(next_state& state) const {
-    if (!sep_.thousands_sep) return max_value<int>();
-    if (state.group == sep_.grouping.end())
-      return state.pos += sep_.grouping.back();
+    if (thousands_sep_.empty()) return max_value<int>();
+    if (state.group == grouping_.end()) return state.pos += grouping_.back();
     if (*state.group <= 0 || *state.group == max_value<char>())
       return max_value<int>();
     state.pos += *state.group++;
@@ -1468,14 +2172,15 @@ template <typename Char> class digit_grouping {
 
  public:
   explicit digit_grouping(locale_ref loc, bool localized = true) {
-    if (localized)
-      sep_ = thousands_sep<Char>(loc);
-    else
-      sep_.thousands_sep = Char();
+    if (!localized) return;
+    auto sep = thousands_sep<Char>(loc);
+    grouping_ = sep.grouping;
+    if (sep.thousands_sep) thousands_sep_.assign(1, sep.thousands_sep);
   }
-  explicit digit_grouping(thousands_sep_result<Char> sep) : sep_(sep) {}
+  digit_grouping(std::string grouping, std::basic_string<Char> sep)
+      : grouping_(std::move(grouping)), thousands_sep_(std::move(sep)) {}
 
-  Char separator() const { return sep_.thousands_sep; }
+  bool has_separator() const { return !thousands_sep_.empty(); }
 
   int count_separators(int num_digits) const {
     int count = 0;
@@ -1498,7 +2203,9 @@ template <typename Char> class digit_grouping {
     for (int i = 0, sep_index = static_cast<int>(separators.size() - 1);
          i < num_digits; ++i) {
       if (num_digits - i == separators[sep_index]) {
-        *out++ = separator();
+        out =
+            copy_str<Char>(thousands_sep_.data(),
+                           thousands_sep_.data() + thousands_sep_.size(), out);
         --sep_index;
       }
       *out++ = static_cast<Char>(digits[to_unsigned(i)]);
@@ -1507,10 +2214,11 @@ template <typename Char> class digit_grouping {
   }
 };
 
+// Writes a decimal integer with digit grouping.
 template <typename OutputIt, typename UInt, typename Char>
-auto write_int_localized(OutputIt out, UInt value, unsigned prefix,
-                         const basic_format_specs<Char>& specs,
-                         const digit_grouping<Char>& grouping) -> OutputIt {
+auto write_int(OutputIt out, UInt value, unsigned prefix,
+               const format_specs<Char>& specs,
+               const digit_grouping<Char>& grouping) -> OutputIt {
   static_assert(std::is_same<uint64_or_128_t<UInt>, UInt>::value, "");
   int num_digits = count_digits(value);
   char digits[40];
@@ -1519,18 +2227,21 @@ auto write_int_localized(OutputIt out, UInt value, unsigned prefix,
                               grouping.count_separators(num_digits));
   return write_padded<align::right>(
       out, specs, size, size, [&](reserve_iterator<OutputIt> it) {
-        if (prefix != 0) *it++ = static_cast<Char>(prefix);
+        if (prefix != 0) {
+          char sign = static_cast<char>(prefix);
+          *it++ = static_cast<Char>(sign);
+        }
         return grouping.apply(it, string_view(digits, to_unsigned(num_digits)));
       });
 }
 
-template <typename OutputIt, typename UInt, typename Char>
-auto write_int_localized(OutputIt& out, UInt value, unsigned prefix,
-                         const basic_format_specs<Char>& specs, locale_ref loc)
-    -> bool {
-  auto grouping = digit_grouping<Char>(loc);
-  out = write_int_localized(out, value, prefix, specs, grouping);
-  return true;
+// Writes a localized value.
+FMT_API auto write_loc(appender out, loc_value value,
+                       const format_specs<>& specs, locale_ref loc) -> bool;
+template <typename OutputIt, typename Char>
+inline auto write_loc(OutputIt, loc_value, const format_specs<Char>&,
+                      locale_ref) -> bool {
+  return false;
 }
 
 FMT_CONSTEXPR inline void prefix_append(unsigned& prefix, unsigned value) {
@@ -1559,21 +2270,37 @@ FMT_CONSTEXPR auto make_write_int_arg(T value, sign_t sign)
   return {abs_value, prefix};
 }
 
+template <typename Char = char> struct loc_writer {
+  buffer_appender<Char> out;
+  const format_specs<Char>& specs;
+  std::basic_string<Char> sep;
+  std::string grouping;
+  std::basic_string<Char> decimal_point;
+
+  template <typename T, FMT_ENABLE_IF(is_integer<T>::value)>
+  auto operator()(T value) -> bool {
+    auto arg = make_write_int_arg(value, specs.sign);
+    write_int(out, static_cast<uint64_or_128_t<T>>(arg.abs_value), arg.prefix,
+              specs, digit_grouping<Char>(grouping, sep));
+    return true;
+  }
+
+  template <typename T, FMT_ENABLE_IF(!is_integer<T>::value)>
+  auto operator()(T) -> bool {
+    return false;
+  }
+};
+
 template <typename Char, typename OutputIt, typename T>
 FMT_CONSTEXPR FMT_INLINE auto write_int(OutputIt out, write_int_arg<T> arg,
-                                        const basic_format_specs<Char>& specs,
-                                        locale_ref loc) -> OutputIt {
+                                        const format_specs<Char>& specs,
+                                        locale_ref) -> OutputIt {
   static_assert(std::is_same<T, uint32_or_64_or_128_t<T>>::value, "");
   auto abs_value = arg.abs_value;
   auto prefix = arg.prefix;
   switch (specs.type) {
   case presentation_type::none:
   case presentation_type::dec: {
-    if (specs.localized &&
-        write_int_localized(out, static_cast<uint64_or_128_t<T>>(abs_value),
-                            prefix, specs, loc)) {
-      return out;
-    }
     auto num_digits = count_digits(abs_value);
     return write_int(
         out, num_digits, prefix, specs, [=](reserve_iterator<OutputIt> it) {
@@ -1616,13 +2343,13 @@ FMT_CONSTEXPR FMT_INLINE auto write_int(OutputIt out, write_int_arg<T> arg,
   case presentation_type::chr:
     return write_char(out, static_cast<Char>(abs_value), specs);
   default:
-    throw_format_error("invalid type specifier");
+    throw_format_error("invalid format specifier");
   }
   return out;
 }
 template <typename Char, typename OutputIt, typename T>
 FMT_CONSTEXPR FMT_NOINLINE auto write_int_noinline(
-    OutputIt out, write_int_arg<T> arg, const basic_format_specs<Char>& specs,
+    OutputIt out, write_int_arg<T> arg, const format_specs<Char>& specs,
     locale_ref loc) -> OutputIt {
   return write_int(out, arg, specs, loc);
 }
@@ -1631,8 +2358,9 @@ template <typename Char, typename OutputIt, typename T,
                         !std::is_same<T, bool>::value &&
                         std::is_same<OutputIt, buffer_appender<Char>>::value)>
 FMT_CONSTEXPR FMT_INLINE auto write(OutputIt out, T value,
-                                    const basic_format_specs<Char>& specs,
+                                    const format_specs<Char>& specs,
                                     locale_ref loc) -> OutputIt {
+  if (specs.localized && write_loc(out, value, specs, loc)) return out;
   return write_int_noinline(out, make_write_int_arg(value, specs.sign), specs,
                             loc);
 }
@@ -1642,48 +2370,179 @@ template <typename Char, typename OutputIt, typename T,
                         !std::is_same<T, bool>::value &&
                         !std::is_same<OutputIt, buffer_appender<Char>>::value)>
 FMT_CONSTEXPR FMT_INLINE auto write(OutputIt out, T value,
-                                    const basic_format_specs<Char>& specs,
+                                    const format_specs<Char>& specs,
                                     locale_ref loc) -> OutputIt {
+  if (specs.localized && write_loc(out, value, specs, loc)) return out;
   return write_int(out, make_write_int_arg(value, specs.sign), specs, loc);
 }
 
+// An output iterator that counts the number of objects written to it and
+// discards them.
+class counting_iterator {
+ private:
+  size_t count_;
+
+ public:
+  using iterator_category = std::output_iterator_tag;
+  using difference_type = std::ptrdiff_t;
+  using pointer = void;
+  using reference = void;
+  FMT_UNCHECKED_ITERATOR(counting_iterator);
+
+  struct value_type {
+    template <typename T> FMT_CONSTEXPR void operator=(const T&) {}
+  };
+
+  FMT_CONSTEXPR counting_iterator() : count_(0) {}
+
+  FMT_CONSTEXPR size_t count() const { return count_; }
+
+  FMT_CONSTEXPR counting_iterator& operator++() {
+    ++count_;
+    return *this;
+  }
+  FMT_CONSTEXPR counting_iterator operator++(int) {
+    auto it = *this;
+    ++*this;
+    return it;
+  }
+
+  FMT_CONSTEXPR friend counting_iterator operator+(counting_iterator it,
+                                                   difference_type n) {
+    it.count_ += static_cast<size_t>(n);
+    return it;
+  }
+
+  FMT_CONSTEXPR value_type operator*() const { return {}; }
+};
+
 template <typename Char, typename OutputIt>
 FMT_CONSTEXPR auto write(OutputIt out, basic_string_view<Char> s,
-                         const basic_format_specs<Char>& specs) -> OutputIt {
+                         const format_specs<Char>& specs) -> OutputIt {
   auto data = s.data();
   auto size = s.size();
   if (specs.precision >= 0 && to_unsigned(specs.precision) < size)
     size = code_point_index(s, to_unsigned(specs.precision));
-  auto width =
-      specs.width != 0 ? compute_width(basic_string_view<Char>(data, size)) : 0;
+  bool is_debug = specs.type == presentation_type::debug;
+  size_t width = 0;
+  if (specs.width != 0) {
+    if (is_debug)
+      width = write_escaped_string(counting_iterator{}, s).count();
+    else
+      width = compute_width(basic_string_view<Char>(data, size));
+  }
   return write_padded(out, specs, size, width,
                       [=](reserve_iterator<OutputIt> it) {
+                        if (is_debug) return write_escaped_string(it, s);
                         return copy_str<Char>(data, data + size, it);
                       });
 }
 template <typename Char, typename OutputIt>
 FMT_CONSTEXPR auto write(OutputIt out,
                          basic_string_view<type_identity_t<Char>> s,
-                         const basic_format_specs<Char>& specs, locale_ref)
+                         const format_specs<Char>& specs, locale_ref)
     -> OutputIt {
-  check_string_type_spec(specs.type);
   return write(out, s, specs);
 }
 template <typename Char, typename OutputIt>
 FMT_CONSTEXPR auto write(OutputIt out, const Char* s,
-                         const basic_format_specs<Char>& specs, locale_ref)
+                         const format_specs<Char>& specs, locale_ref)
     -> OutputIt {
-  return check_cstring_type_spec(specs.type)
+  return specs.type != presentation_type::pointer
              ? write(out, basic_string_view<Char>(s), specs, {})
-             : write_ptr<Char>(out, to_uintptr(s), &specs);
+             : write_ptr<Char>(out, bit_cast<uintptr_t>(s), &specs);
+}
+
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(is_integral<T>::value &&
+                        !std::is_same<T, bool>::value &&
+                        !std::is_same<T, Char>::value)>
+FMT_CONSTEXPR auto write(OutputIt out, T value) -> OutputIt {
+  auto abs_value = static_cast<uint32_or_64_or_128_t<T>>(value);
+  bool negative = is_negative(value);
+  // Don't do -abs_value since it trips unsigned-integer-overflow sanitizer.
+  if (negative) abs_value = ~abs_value + 1;
+  int num_digits = count_digits(abs_value);
+  auto size = (negative ? 1 : 0) + static_cast<size_t>(num_digits);
+  auto it = reserve(out, size);
+  if (auto ptr = to_pointer<Char>(it, size)) {
+    if (negative) *ptr++ = static_cast<Char>('-');
+    format_decimal<Char>(ptr, abs_value, num_digits);
+    return out;
+  }
+  if (negative) *it++ = static_cast<Char>('-');
+  it = format_decimal<Char>(it, abs_value, num_digits).end;
+  return base_iterator(out, it);
+}
+
+// A floating-point presentation format.
+enum class float_format : unsigned char {
+  general,  // General: exponent notation or fixed point based on magnitude.
+  exp,      // Exponent notation with the default precision of 6, e.g. 1.2e-3.
+  fixed,    // Fixed point with the default precision of 6, e.g. 0.0012.
+  hex
+};
+
+struct float_specs {
+  int precision;
+  float_format format : 8;
+  sign_t sign : 8;
+  bool upper : 1;
+  bool locale : 1;
+  bool binary32 : 1;
+  bool showpoint : 1;
+};
+
+template <typename ErrorHandler = error_handler, typename Char>
+FMT_CONSTEXPR auto parse_float_type_spec(const format_specs<Char>& specs,
+                                         ErrorHandler&& eh = {})
+    -> float_specs {
+  auto result = float_specs();
+  result.showpoint = specs.alt;
+  result.locale = specs.localized;
+  switch (specs.type) {
+  case presentation_type::none:
+    result.format = float_format::general;
+    break;
+  case presentation_type::general_upper:
+    result.upper = true;
+    FMT_FALLTHROUGH;
+  case presentation_type::general_lower:
+    result.format = float_format::general;
+    break;
+  case presentation_type::exp_upper:
+    result.upper = true;
+    FMT_FALLTHROUGH;
+  case presentation_type::exp_lower:
+    result.format = float_format::exp;
+    result.showpoint |= specs.precision != 0;
+    break;
+  case presentation_type::fixed_upper:
+    result.upper = true;
+    FMT_FALLTHROUGH;
+  case presentation_type::fixed_lower:
+    result.format = float_format::fixed;
+    result.showpoint |= specs.precision != 0;
+    break;
+  case presentation_type::hexfloat_upper:
+    result.upper = true;
+    FMT_FALLTHROUGH;
+  case presentation_type::hexfloat_lower:
+    result.format = float_format::hex;
+    break;
+  default:
+    eh.on_error("invalid format specifier");
+    break;
+  }
+  return result;
 }
 
 template <typename Char, typename OutputIt>
-FMT_CONSTEXPR20 auto write_nonfinite(OutputIt out, bool isinf,
-                                     basic_format_specs<Char> specs,
+FMT_CONSTEXPR20 auto write_nonfinite(OutputIt out, bool isnan,
+                                     format_specs<Char> specs,
                                      const float_specs& fspecs) -> OutputIt {
   auto str =
-      isinf ? (fspecs.upper ? "INF" : "inf") : (fspecs.upper ? "NAN" : "nan");
+      isnan ? (fspecs.upper ? "NAN" : "nan") : (fspecs.upper ? "INF" : "inf");
   constexpr size_t str_size = 3;
   auto sign = fspecs.sign;
   auto size = str_size + (sign ? 1 : 0);
@@ -1704,12 +2563,12 @@ struct big_decimal_fp {
   int exponent;
 };
 
-constexpr auto get_significand_size(const big_decimal_fp& fp) -> int {
-  return fp.significand_size;
+constexpr auto get_significand_size(const big_decimal_fp& f) -> int {
+  return f.significand_size;
 }
 template <typename T>
-inline auto get_significand_size(const dragonbox::decimal_fp<T>& fp) -> int {
-  return count_digits(fp.significand);
+inline auto get_significand_size(const dragonbox::decimal_fp<T>& f) -> int {
+  return count_digits(f.significand);
 }
 
 template <typename Char, typename OutputIt>
@@ -1726,7 +2585,7 @@ template <typename Char, typename OutputIt, typename T, typename Grouping>
 FMT_CONSTEXPR20 auto write_significand(OutputIt out, T significand,
                                        int significand_size, int exponent,
                                        const Grouping& grouping) -> OutputIt {
-  if (!grouping.separator()) {
+  if (!grouping.has_separator()) {
     out = write_significand<Char>(out, significand, significand_size);
     return detail::fill_n(out, exponent, static_cast<Char>('0'));
   }
@@ -1747,7 +2606,7 @@ inline auto write_significand(Char* out, UInt significand, int significand_size,
   int floating_size = significand_size - integral_size;
   for (int i = floating_size / 2; i > 0; --i) {
     out -= 2;
-    copy2(out, digits2(significand % 100));
+    copy2(out, digits2(static_cast<std::size_t>(significand % 100)));
     significand /= 100;
   }
   if (floating_size % 2 != 0) {
@@ -1788,7 +2647,7 @@ FMT_CONSTEXPR20 auto write_significand(OutputIt out, T significand,
                                        int significand_size, int integral_size,
                                        Char decimal_point,
                                        const Grouping& grouping) -> OutputIt {
-  if (!grouping.separator()) {
+  if (!grouping.has_separator()) {
     return write_significand(out, significand, significand_size, integral_size,
                              decimal_point);
   }
@@ -1803,13 +2662,13 @@ FMT_CONSTEXPR20 auto write_significand(OutputIt out, T significand,
 
 template <typename OutputIt, typename DecimalFP, typename Char,
           typename Grouping = digit_grouping<Char>>
-FMT_CONSTEXPR20 auto do_write_float(OutputIt out, const DecimalFP& fp,
-                                    const basic_format_specs<Char>& specs,
+FMT_CONSTEXPR20 auto do_write_float(OutputIt out, const DecimalFP& f,
+                                    const format_specs<Char>& specs,
                                     float_specs fspecs, locale_ref loc)
     -> OutputIt {
-  auto significand = fp.significand;
-  int significand_size = get_significand_size(fp);
-  constexpr Char zero = static_cast<Char>('0');
+  auto significand = f.significand;
+  int significand_size = get_significand_size(f);
+  const Char zero = static_cast<Char>('0');
   auto sign = fspecs.sign;
   size_t size = to_unsigned(significand_size) + (sign ? 1 : 0);
   using iterator = reserve_iterator<OutputIt>;
@@ -1817,7 +2676,7 @@ FMT_CONSTEXPR20 auto do_write_float(OutputIt out, const DecimalFP& fp,
   Char decimal_point =
       fspecs.locale ? detail::decimal_point<Char>(loc) : static_cast<Char>('.');
 
-  int output_exp = fp.exponent + significand_size - 1;
+  int output_exp = f.exponent + significand_size - 1;
   auto use_exp_format = [=]() {
     if (fspecs.format == float_format::exp) return true;
     if (fspecs.format != float_format::general) return false;
@@ -1855,25 +2714,23 @@ FMT_CONSTEXPR20 auto do_write_float(OutputIt out, const DecimalFP& fp,
                            : base_iterator(out, write(reserve(out, size)));
   }
 
-  int exp = fp.exponent + significand_size;
-  if (fp.exponent >= 0) {
+  int exp = f.exponent + significand_size;
+  if (f.exponent >= 0) {
     // 1234e5 -> 123400000[.0+]
-    size += to_unsigned(fp.exponent);
+    size += to_unsigned(f.exponent);
     int num_zeros = fspecs.precision - exp;
-#ifdef FMT_FUZZ
-    if (num_zeros > 5000)
-      throw std::runtime_error("fuzz mode - avoiding excessive cpu use");
-#endif
+    abort_fuzzing_if(num_zeros > 5000);
     if (fspecs.showpoint) {
-      if (num_zeros <= 0 && fspecs.format != float_format::fixed) num_zeros = 1;
-      if (num_zeros > 0) size += to_unsigned(num_zeros) + 1;
+      ++size;
+      if (num_zeros <= 0 && fspecs.format != float_format::fixed) num_zeros = 0;
+      if (num_zeros > 0) size += to_unsigned(num_zeros);
     }
     auto grouping = Grouping(loc, fspecs.locale);
-    size += to_unsigned(grouping.count_separators(significand_size));
+    size += to_unsigned(grouping.count_separators(exp));
     return write_padded<align::right>(out, specs, size, [&](iterator it) {
       if (sign) *it++ = detail::sign<Char>(sign);
       it = write_significand<Char>(it, significand, significand_size,
-                                   fp.exponent, grouping);
+                                   f.exponent, grouping);
       if (!fspecs.showpoint) return it;
       *it++ = decimal_point;
       return num_zeros > 0 ? detail::fill_n(it, num_zeros, zero) : it;
@@ -1883,7 +2740,7 @@ FMT_CONSTEXPR20 auto do_write_float(OutputIt out, const DecimalFP& fp,
     int num_zeros = fspecs.showpoint ? fspecs.precision - significand_size : 0;
     size += 1 + to_unsigned(num_zeros > 0 ? num_zeros : 0);
     auto grouping = Grouping(loc, fspecs.locale);
-    size += to_unsigned(grouping.count_separators(significand_size));
+    size += to_unsigned(grouping.count_separators(exp));
     return write_padded<align::right>(out, specs, size, [&](iterator it) {
       if (sign) *it++ = detail::sign<Char>(sign);
       it = write_significand(it, significand, significand_size, exp,
@@ -1913,7 +2770,7 @@ template <typename Char> class fallback_digit_grouping {
  public:
   constexpr fallback_digit_grouping(locale_ref, bool) {}
 
-  constexpr Char separator() const { return Char(); }
+  constexpr bool has_separator() const { return false; }
 
   constexpr int count_separators(int) const { return 0; }
 
@@ -1924,67 +2781,1044 @@ template <typename Char> class fallback_digit_grouping {
 };
 
 template <typename OutputIt, typename DecimalFP, typename Char>
-FMT_CONSTEXPR20 auto write_float(OutputIt out, const DecimalFP& fp,
-                                 const basic_format_specs<Char>& specs,
+FMT_CONSTEXPR20 auto write_float(OutputIt out, const DecimalFP& f,
+                                 const format_specs<Char>& specs,
                                  float_specs fspecs, locale_ref loc)
     -> OutputIt {
   if (is_constant_evaluated()) {
     return do_write_float<OutputIt, DecimalFP, Char,
-                          fallback_digit_grouping<Char>>(out, fp, specs, fspecs,
+                          fallback_digit_grouping<Char>>(out, f, specs, fspecs,
                                                          loc);
   } else {
-    return do_write_float(out, fp, specs, fspecs, loc);
+    return do_write_float(out, f, specs, fspecs, loc);
   }
 }
 
-template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-FMT_CONSTEXPR20 bool isinf(T value) {
-  if (is_constant_evaluated()) {
-#if defined(__cpp_if_constexpr)
-    if constexpr (std::numeric_limits<double>::is_iec559) {
-      auto bits = detail::bit_cast<uint64_t>(static_cast<double>(value));
-      constexpr auto significand_bits =
-          dragonbox::float_info<double>::significand_bits;
-      return (bits & exponent_mask<double>()) &&
-             !(bits & ((uint64_t(1) << significand_bits) - 1));
-    }
-#endif
-  }
-  return std::isinf(value);
+template <typename T> constexpr bool isnan(T value) {
+  return !(value >= value);  // std::isnan doesn't support __float128.
 }
 
-template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+template <typename T, typename Enable = void>
+struct has_isfinite : std::false_type {};
+
+template <typename T>
+struct has_isfinite<T, enable_if_t<sizeof(std::isfinite(T())) != 0>>
+    : std::true_type {};
+
+template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value&&
+                                        has_isfinite<T>::value)>
 FMT_CONSTEXPR20 bool isfinite(T value) {
-  if (is_constant_evaluated()) {
-#if defined(__cpp_if_constexpr)
-    if constexpr (std::numeric_limits<double>::is_iec559) {
-      auto bits = detail::bit_cast<uint64_t>(static_cast<double>(value));
-      return (bits & exponent_mask<double>()) != exponent_mask<double>();
-    }
-#endif
-  }
+  constexpr T inf = T(std::numeric_limits<double>::infinity());
+  if (is_constant_evaluated())
+    return !detail::isnan(value) && value < inf && value > -inf;
   return std::isfinite(value);
 }
+template <typename T, FMT_ENABLE_IF(!has_isfinite<T>::value)>
+FMT_CONSTEXPR bool isfinite(T value) {
+  T inf = T(std::numeric_limits<double>::infinity());
+  // std::isfinite doesn't support __float128.
+  return !detail::isnan(value) && value < inf && value > -inf;
+}
 
-template <typename T, FMT_ENABLE_IF(std::is_floating_point<T>::value)>
+template <typename T, FMT_ENABLE_IF(is_floating_point<T>::value)>
 FMT_INLINE FMT_CONSTEXPR bool signbit(T value) {
   if (is_constant_evaluated()) {
 #ifdef __cpp_if_constexpr
     if constexpr (std::numeric_limits<double>::is_iec559) {
       auto bits = detail::bit_cast<uint64_t>(static_cast<double>(value));
-      return (bits & (uint64_t(1) << (num_bits<uint64_t>() - 1))) != 0;
+      return (bits >> (num_bits<uint64_t>() - 1)) != 0;
     }
 #endif
   }
-  return std::signbit(value);
+  return std::signbit(static_cast<double>(value));
+}
+
+enum class round_direction { unknown, up, down };
+
+// Given the divisor (normally a power of 10), the remainder = v % divisor for
+// some number v and the error, returns whether v should be rounded up, down, or
+// whether the rounding direction can't be determined due to error.
+// error should be less than divisor / 2.
+FMT_CONSTEXPR inline round_direction get_round_direction(uint64_t divisor,
+                                                         uint64_t remainder,
+                                                         uint64_t error) {
+  FMT_ASSERT(remainder < divisor, "");  // divisor - remainder won't overflow.
+  FMT_ASSERT(error < divisor, "");      // divisor - error won't overflow.
+  FMT_ASSERT(error < divisor - error, "");  // error * 2 won't overflow.
+  // Round down if (remainder + error) * 2 <= divisor.
+  if (remainder <= divisor - remainder && error * 2 <= divisor - remainder * 2)
+    return round_direction::down;
+  // Round up if (remainder - error) * 2 >= divisor.
+  if (remainder >= error &&
+      remainder - error >= divisor - (remainder - error)) {
+    return round_direction::up;
+  }
+  return round_direction::unknown;
 }
 
-template <typename Char, typename OutputIt, typename T,
-          FMT_ENABLE_IF(std::is_floating_point<T>::value)>
-FMT_CONSTEXPR20 auto write(OutputIt out, T value,
-                           basic_format_specs<Char> specs, locale_ref loc = {})
+namespace digits {
+enum result {
+  more,  // Generate more digits.
+  done,  // Done generating digits.
+  error  // Digit generation cancelled due to an error.
+};
+}
+
+struct gen_digits_handler {
+  char* buf;
+  int size;
+  int precision;
+  int exp10;
+  bool fixed;
+
+  FMT_CONSTEXPR digits::result on_digit(char digit, uint64_t divisor,
+                                        uint64_t remainder, uint64_t error,
+                                        bool integral) {
+    FMT_ASSERT(remainder < divisor, "");
+    buf[size++] = digit;
+    if (!integral && error >= remainder) return digits::error;
+    if (size < precision) return digits::more;
+    if (!integral) {
+      // Check if error * 2 < divisor with overflow prevention.
+      // The check is not needed for the integral part because error = 1
+      // and divisor > (1 << 32) there.
+      if (error >= divisor || error >= divisor - error) return digits::error;
+    } else {
+      FMT_ASSERT(error == 1 && divisor > 2, "");
+    }
+    auto dir = get_round_direction(divisor, remainder, error);
+    if (dir != round_direction::up)
+      return dir == round_direction::down ? digits::done : digits::error;
+    ++buf[size - 1];
+    for (int i = size - 1; i > 0 && buf[i] > '9'; --i) {
+      buf[i] = '0';
+      ++buf[i - 1];
+    }
+    if (buf[0] > '9') {
+      buf[0] = '1';
+      if (fixed)
+        buf[size++] = '0';
+      else
+        ++exp10;
+    }
+    return digits::done;
+  }
+};
+
+inline FMT_CONSTEXPR20 void adjust_precision(int& precision, int exp10) {
+  // Adjust fixed precision by exponent because it is relative to decimal
+  // point.
+  if (exp10 > 0 && precision > max_value<int>() - exp10)
+    FMT_THROW(format_error("number is too big"));
+  precision += exp10;
+}
+
+// Generates output using the Grisu digit-gen algorithm.
+// error: the size of the region (lower, upper) outside of which numbers
+// definitely do not round to value (Delta in Grisu3).
+FMT_INLINE FMT_CONSTEXPR20 auto grisu_gen_digits(fp value, uint64_t error,
+                                                 int& exp,
+                                                 gen_digits_handler& handler)
+    -> digits::result {
+  const fp one(1ULL << -value.e, value.e);
+  // The integral part of scaled value (p1 in Grisu) = value / one. It cannot be
+  // zero because it contains a product of two 64-bit numbers with MSB set (due
+  // to normalization) - 1, shifted right by at most 60 bits.
+  auto integral = static_cast<uint32_t>(value.f >> -one.e);
+  FMT_ASSERT(integral != 0, "");
+  FMT_ASSERT(integral == value.f >> -one.e, "");
+  // The fractional part of scaled value (p2 in Grisu) c = value % one.
+  uint64_t fractional = value.f & (one.f - 1);
+  exp = count_digits(integral);  // kappa in Grisu.
+  // Non-fixed formats require at least one digit and no precision adjustment.
+  if (handler.fixed) {
+    adjust_precision(handler.precision, exp + handler.exp10);
+    // Check if precision is satisfied just by leading zeros, e.g.
+    // format("{:.2f}", 0.001) gives "0.00" without generating any digits.
+    if (handler.precision <= 0) {
+      if (handler.precision < 0) return digits::done;
+      // Divide by 10 to prevent overflow.
+      uint64_t divisor = data::power_of_10_64[exp - 1] << -one.e;
+      auto dir = get_round_direction(divisor, value.f / 10, error * 10);
+      if (dir == round_direction::unknown) return digits::error;
+      handler.buf[handler.size++] = dir == round_direction::up ? '1' : '0';
+      return digits::done;
+    }
+  }
+  // Generate digits for the integral part. This can produce up to 10 digits.
+  do {
+    uint32_t digit = 0;
+    auto divmod_integral = [&](uint32_t divisor) {
+      digit = integral / divisor;
+      integral %= divisor;
+    };
+    // This optimization by Milo Yip reduces the number of integer divisions by
+    // one per iteration.
+    switch (exp) {
+    case 10:
+      divmod_integral(1000000000);
+      break;
+    case 9:
+      divmod_integral(100000000);
+      break;
+    case 8:
+      divmod_integral(10000000);
+      break;
+    case 7:
+      divmod_integral(1000000);
+      break;
+    case 6:
+      divmod_integral(100000);
+      break;
+    case 5:
+      divmod_integral(10000);
+      break;
+    case 4:
+      divmod_integral(1000);
+      break;
+    case 3:
+      divmod_integral(100);
+      break;
+    case 2:
+      divmod_integral(10);
+      break;
+    case 1:
+      digit = integral;
+      integral = 0;
+      break;
+    default:
+      FMT_ASSERT(false, "invalid number of digits");
+    }
+    --exp;
+    auto remainder = (static_cast<uint64_t>(integral) << -one.e) + fractional;
+    auto result = handler.on_digit(static_cast<char>('0' + digit),
+                                   data::power_of_10_64[exp] << -one.e,
+                                   remainder, error, true);
+    if (result != digits::more) return result;
+  } while (exp > 0);
+  // Generate digits for the fractional part.
+  for (;;) {
+    fractional *= 10;
+    error *= 10;
+    char digit = static_cast<char>('0' + (fractional >> -one.e));
+    fractional &= one.f - 1;
+    --exp;
+    auto result = handler.on_digit(digit, one.f, fractional, error, false);
+    if (result != digits::more) return result;
+  }
+}
+
+class bigint {
+ private:
+  // A bigint is stored as an array of bigits (big digits), with bigit at index
+  // 0 being the least significant one.
+  using bigit = uint32_t;
+  using double_bigit = uint64_t;
+  enum { bigits_capacity = 32 };
+  basic_memory_buffer<bigit, bigits_capacity> bigits_;
+  int exp_;
+
+  FMT_CONSTEXPR20 bigit operator[](int index) const {
+    return bigits_[to_unsigned(index)];
+  }
+  FMT_CONSTEXPR20 bigit& operator[](int index) {
+    return bigits_[to_unsigned(index)];
+  }
+
+  static constexpr const int bigit_bits = num_bits<bigit>();
+
+  friend struct formatter<bigint>;
+
+  FMT_CONSTEXPR20 void subtract_bigits(int index, bigit other, bigit& borrow) {
+    auto result = static_cast<double_bigit>((*this)[index]) - other - borrow;
+    (*this)[index] = static_cast<bigit>(result);
+    borrow = static_cast<bigit>(result >> (bigit_bits * 2 - 1));
+  }
+
+  FMT_CONSTEXPR20 void remove_leading_zeros() {
+    int num_bigits = static_cast<int>(bigits_.size()) - 1;
+    while (num_bigits > 0 && (*this)[num_bigits] == 0) --num_bigits;
+    bigits_.resize(to_unsigned(num_bigits + 1));
+  }
+
+  // Computes *this -= other assuming aligned bigints and *this >= other.
+  FMT_CONSTEXPR20 void subtract_aligned(const bigint& other) {
+    FMT_ASSERT(other.exp_ >= exp_, "unaligned bigints");
+    FMT_ASSERT(compare(*this, other) >= 0, "");
+    bigit borrow = 0;
+    int i = other.exp_ - exp_;
+    for (size_t j = 0, n = other.bigits_.size(); j != n; ++i, ++j)
+      subtract_bigits(i, other.bigits_[j], borrow);
+    while (borrow > 0) subtract_bigits(i, 0, borrow);
+    remove_leading_zeros();
+  }
+
+  FMT_CONSTEXPR20 void multiply(uint32_t value) {
+    const double_bigit wide_value = value;
+    bigit carry = 0;
+    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
+      double_bigit result = bigits_[i] * wide_value + carry;
+      bigits_[i] = static_cast<bigit>(result);
+      carry = static_cast<bigit>(result >> bigit_bits);
+    }
+    if (carry != 0) bigits_.push_back(carry);
+  }
+
+  template <typename UInt, FMT_ENABLE_IF(std::is_same<UInt, uint64_t>::value ||
+                                         std::is_same<UInt, uint128_t>::value)>
+  FMT_CONSTEXPR20 void multiply(UInt value) {
+    using half_uint =
+        conditional_t<std::is_same<UInt, uint128_t>::value, uint64_t, uint32_t>;
+    const int shift = num_bits<half_uint>() - bigit_bits;
+    const UInt lower = static_cast<half_uint>(value);
+    const UInt upper = value >> num_bits<half_uint>();
+    UInt carry = 0;
+    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
+      UInt result = lower * bigits_[i] + static_cast<bigit>(carry);
+      carry = (upper * bigits_[i] << shift) + (result >> bigit_bits) +
+              (carry >> bigit_bits);
+      bigits_[i] = static_cast<bigit>(result);
+    }
+    while (carry != 0) {
+      bigits_.push_back(static_cast<bigit>(carry));
+      carry >>= bigit_bits;
+    }
+  }
+
+  template <typename UInt, FMT_ENABLE_IF(std::is_same<UInt, uint64_t>::value ||
+                                         std::is_same<UInt, uint128_t>::value)>
+  FMT_CONSTEXPR20 void assign(UInt n) {
+    size_t num_bigits = 0;
+    do {
+      bigits_[num_bigits++] = static_cast<bigit>(n);
+      n >>= bigit_bits;
+    } while (n != 0);
+    bigits_.resize(num_bigits);
+    exp_ = 0;
+  }
+
+ public:
+  FMT_CONSTEXPR20 bigint() : exp_(0) {}
+  explicit bigint(uint64_t n) { assign(n); }
+
+  bigint(const bigint&) = delete;
+  void operator=(const bigint&) = delete;
+
+  FMT_CONSTEXPR20 void assign(const bigint& other) {
+    auto size = other.bigits_.size();
+    bigits_.resize(size);
+    auto data = other.bigits_.data();
+    std::copy(data, data + size, make_checked(bigits_.data(), size));
+    exp_ = other.exp_;
+  }
+
+  template <typename Int> FMT_CONSTEXPR20 void operator=(Int n) {
+    FMT_ASSERT(n > 0, "");
+    assign(uint64_or_128_t<Int>(n));
+  }
+
+  FMT_CONSTEXPR20 int num_bigits() const {
+    return static_cast<int>(bigits_.size()) + exp_;
+  }
+
+  FMT_NOINLINE FMT_CONSTEXPR20 bigint& operator<<=(int shift) {
+    FMT_ASSERT(shift >= 0, "");
+    exp_ += shift / bigit_bits;
+    shift %= bigit_bits;
+    if (shift == 0) return *this;
+    bigit carry = 0;
+    for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
+      bigit c = bigits_[i] >> (bigit_bits - shift);
+      bigits_[i] = (bigits_[i] << shift) + carry;
+      carry = c;
+    }
+    if (carry != 0) bigits_.push_back(carry);
+    return *this;
+  }
+
+  template <typename Int> FMT_CONSTEXPR20 bigint& operator*=(Int value) {
+    FMT_ASSERT(value > 0, "");
+    multiply(uint32_or_64_or_128_t<Int>(value));
+    return *this;
+  }
+
+  friend FMT_CONSTEXPR20 int compare(const bigint& lhs, const bigint& rhs) {
+    int num_lhs_bigits = lhs.num_bigits(), num_rhs_bigits = rhs.num_bigits();
+    if (num_lhs_bigits != num_rhs_bigits)
+      return num_lhs_bigits > num_rhs_bigits ? 1 : -1;
+    int i = static_cast<int>(lhs.bigits_.size()) - 1;
+    int j = static_cast<int>(rhs.bigits_.size()) - 1;
+    int end = i - j;
+    if (end < 0) end = 0;
+    for (; i >= end; --i, --j) {
+      bigit lhs_bigit = lhs[i], rhs_bigit = rhs[j];
+      if (lhs_bigit != rhs_bigit) return lhs_bigit > rhs_bigit ? 1 : -1;
+    }
+    if (i != j) return i > j ? 1 : -1;
+    return 0;
+  }
+
+  // Returns compare(lhs1 + lhs2, rhs).
+  friend FMT_CONSTEXPR20 int add_compare(const bigint& lhs1, const bigint& lhs2,
+                                         const bigint& rhs) {
+    auto minimum = [](int a, int b) { return a < b ? a : b; };
+    auto maximum = [](int a, int b) { return a > b ? a : b; };
+    int max_lhs_bigits = maximum(lhs1.num_bigits(), lhs2.num_bigits());
+    int num_rhs_bigits = rhs.num_bigits();
+    if (max_lhs_bigits + 1 < num_rhs_bigits) return -1;
+    if (max_lhs_bigits > num_rhs_bigits) return 1;
+    auto get_bigit = [](const bigint& n, int i) -> bigit {
+      return i >= n.exp_ && i < n.num_bigits() ? n[i - n.exp_] : 0;
+    };
+    double_bigit borrow = 0;
+    int min_exp = minimum(minimum(lhs1.exp_, lhs2.exp_), rhs.exp_);
+    for (int i = num_rhs_bigits - 1; i >= min_exp; --i) {
+      double_bigit sum =
+          static_cast<double_bigit>(get_bigit(lhs1, i)) + get_bigit(lhs2, i);
+      bigit rhs_bigit = get_bigit(rhs, i);
+      if (sum > rhs_bigit + borrow) return 1;
+      borrow = rhs_bigit + borrow - sum;
+      if (borrow > 1) return -1;
+      borrow <<= bigit_bits;
+    }
+    return borrow != 0 ? -1 : 0;
+  }
+
+  // Assigns pow(10, exp) to this bigint.
+  FMT_CONSTEXPR20 void assign_pow10(int exp) {
+    FMT_ASSERT(exp >= 0, "");
+    if (exp == 0) return *this = 1;
+    // Find the top bit.
+    int bitmask = 1;
+    while (exp >= bitmask) bitmask <<= 1;
+    bitmask >>= 1;
+    // pow(10, exp) = pow(5, exp) * pow(2, exp). First compute pow(5, exp) by
+    // repeated squaring and multiplication.
+    *this = 5;
+    bitmask >>= 1;
+    while (bitmask != 0) {
+      square();
+      if ((exp & bitmask) != 0) *this *= 5;
+      bitmask >>= 1;
+    }
+    *this <<= exp;  // Multiply by pow(2, exp) by shifting.
+  }
+
+  FMT_CONSTEXPR20 void square() {
+    int num_bigits = static_cast<int>(bigits_.size());
+    int num_result_bigits = 2 * num_bigits;
+    basic_memory_buffer<bigit, bigits_capacity> n(std::move(bigits_));
+    bigits_.resize(to_unsigned(num_result_bigits));
+    auto sum = uint128_t();
+    for (int bigit_index = 0; bigit_index < num_bigits; ++bigit_index) {
+      // Compute bigit at position bigit_index of the result by adding
+      // cross-product terms n[i] * n[j] such that i + j == bigit_index.
+      for (int i = 0, j = bigit_index; j >= 0; ++i, --j) {
+        // Most terms are multiplied twice which can be optimized in the future.
+        sum += static_cast<double_bigit>(n[i]) * n[j];
+      }
+      (*this)[bigit_index] = static_cast<bigit>(sum);
+      sum >>= num_bits<bigit>();  // Compute the carry.
+    }
+    // Do the same for the top half.
+    for (int bigit_index = num_bigits; bigit_index < num_result_bigits;
+         ++bigit_index) {
+      for (int j = num_bigits - 1, i = bigit_index - j; i < num_bigits;)
+        sum += static_cast<double_bigit>(n[i++]) * n[j--];
+      (*this)[bigit_index] = static_cast<bigit>(sum);
+      sum >>= num_bits<bigit>();
+    }
+    remove_leading_zeros();
+    exp_ *= 2;
+  }
+
+  // If this bigint has a bigger exponent than other, adds trailing zero to make
+  // exponents equal. This simplifies some operations such as subtraction.
+  FMT_CONSTEXPR20 void align(const bigint& other) {
+    int exp_difference = exp_ - other.exp_;
+    if (exp_difference <= 0) return;
+    int num_bigits = static_cast<int>(bigits_.size());
+    bigits_.resize(to_unsigned(num_bigits + exp_difference));
+    for (int i = num_bigits - 1, j = i + exp_difference; i >= 0; --i, --j)
+      bigits_[j] = bigits_[i];
+    std::uninitialized_fill_n(bigits_.data(), exp_difference, 0);
+    exp_ -= exp_difference;
+  }
+
+  // Divides this bignum by divisor, assigning the remainder to this and
+  // returning the quotient.
+  FMT_CONSTEXPR20 int divmod_assign(const bigint& divisor) {
+    FMT_ASSERT(this != &divisor, "");
+    if (compare(*this, divisor) < 0) return 0;
+    FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1u] != 0, "");
+    align(divisor);
+    int quotient = 0;
+    do {
+      subtract_aligned(divisor);
+      ++quotient;
+    } while (compare(*this, divisor) >= 0);
+    return quotient;
+  }
+};
+
+// format_dragon flags.
+enum dragon {
+  predecessor_closer = 1,
+  fixup = 2,  // Run fixup to correct exp10 which can be off by one.
+  fixed = 4,
+};
+
+// Formats a floating-point number using a variation of the Fixed-Precision
+// Positive Floating-Point Printout ((FPP)^2) algorithm by Steele & White:
+// https://fmt.dev/papers/p372-steele.pdf.
+FMT_CONSTEXPR20 inline void format_dragon(basic_fp<uint128_t> value,
+                                          unsigned flags, int num_digits,
+                                          buffer<char>& buf, int& exp10) {
+  bigint numerator;    // 2 * R in (FPP)^2.
+  bigint denominator;  // 2 * S in (FPP)^2.
+  // lower and upper are differences between value and corresponding boundaries.
+  bigint lower;             // (M^- in (FPP)^2).
+  bigint upper_store;       // upper's value if different from lower.
+  bigint* upper = nullptr;  // (M^+ in (FPP)^2).
+  // Shift numerator and denominator by an extra bit or two (if lower boundary
+  // is closer) to make lower and upper integers. This eliminates multiplication
+  // by 2 during later computations.
+  bool is_predecessor_closer = (flags & dragon::predecessor_closer) != 0;
+  int shift = is_predecessor_closer ? 2 : 1;
+  if (value.e >= 0) {
+    numerator = value.f;
+    numerator <<= value.e + shift;
+    lower = 1;
+    lower <<= value.e;
+    if (is_predecessor_closer) {
+      upper_store = 1;
+      upper_store <<= value.e + 1;
+      upper = &upper_store;
+    }
+    denominator.assign_pow10(exp10);
+    denominator <<= shift;
+  } else if (exp10 < 0) {
+    numerator.assign_pow10(-exp10);
+    lower.assign(numerator);
+    if (is_predecessor_closer) {
+      upper_store.assign(numerator);
+      upper_store <<= 1;
+      upper = &upper_store;
+    }
+    numerator *= value.f;
+    numerator <<= shift;
+    denominator = 1;
+    denominator <<= shift - value.e;
+  } else {
+    numerator = value.f;
+    numerator <<= shift;
+    denominator.assign_pow10(exp10);
+    denominator <<= shift - value.e;
+    lower = 1;
+    if (is_predecessor_closer) {
+      upper_store = 1ULL << 1;
+      upper = &upper_store;
+    }
+  }
+  int even = static_cast<int>((value.f & 1) == 0);
+  if (!upper) upper = &lower;
+  if ((flags & dragon::fixup) != 0) {
+    if (add_compare(numerator, *upper, denominator) + even <= 0) {
+      --exp10;
+      numerator *= 10;
+      if (num_digits < 0) {
+        lower *= 10;
+        if (upper != &lower) *upper *= 10;
+      }
+    }
+    if ((flags & dragon::fixed) != 0) adjust_precision(num_digits, exp10 + 1);
+  }
+  // Invariant: value == (numerator / denominator) * pow(10, exp10).
+  if (num_digits < 0) {
+    // Generate the shortest representation.
+    num_digits = 0;
+    char* data = buf.data();
+    for (;;) {
+      int digit = numerator.divmod_assign(denominator);
+      bool low = compare(numerator, lower) - even < 0;  // numerator <[=] lower.
+      // numerator + upper >[=] pow10:
+      bool high = add_compare(numerator, *upper, denominator) + even > 0;
+      data[num_digits++] = static_cast<char>('0' + digit);
+      if (low || high) {
+        if (!low) {
+          ++data[num_digits - 1];
+        } else if (high) {
+          int result = add_compare(numerator, numerator, denominator);
+          // Round half to even.
+          if (result > 0 || (result == 0 && (digit % 2) != 0))
+            ++data[num_digits - 1];
+        }
+        buf.try_resize(to_unsigned(num_digits));
+        exp10 -= num_digits - 1;
+        return;
+      }
+      numerator *= 10;
+      lower *= 10;
+      if (upper != &lower) *upper *= 10;
+    }
+  }
+  // Generate the given number of digits.
+  exp10 -= num_digits - 1;
+  if (num_digits == 0) {
+    denominator *= 10;
+    auto digit = add_compare(numerator, numerator, denominator) > 0 ? '1' : '0';
+    buf.push_back(digit);
+    return;
+  }
+  buf.try_resize(to_unsigned(num_digits));
+  for (int i = 0; i < num_digits - 1; ++i) {
+    int digit = numerator.divmod_assign(denominator);
+    buf[i] = static_cast<char>('0' + digit);
+    numerator *= 10;
+  }
+  int digit = numerator.divmod_assign(denominator);
+  auto result = add_compare(numerator, numerator, denominator);
+  if (result > 0 || (result == 0 && (digit % 2) != 0)) {
+    if (digit == 9) {
+      const auto overflow = '0' + 10;
+      buf[num_digits - 1] = overflow;
+      // Propagate the carry.
+      for (int i = num_digits - 1; i > 0 && buf[i] == overflow; --i) {
+        buf[i] = '0';
+        ++buf[i - 1];
+      }
+      if (buf[0] == overflow) {
+        buf[0] = '1';
+        ++exp10;
+      }
+      return;
+    }
+    ++digit;
+  }
+  buf[num_digits - 1] = static_cast<char>('0' + digit);
+}
+
+// Formats a floating-point number using the hexfloat format.
+template <typename Float, FMT_ENABLE_IF(!is_double_double<Float>::value)>
+FMT_CONSTEXPR20 void format_hexfloat(Float value, int precision,
+                                     float_specs specs, buffer<char>& buf) {
+  // float is passed as double to reduce the number of instantiations and to
+  // simplify implementation.
+  static_assert(!std::is_same<Float, float>::value, "");
+
+  using info = dragonbox::float_info<Float>;
+
+  // Assume Float is in the format [sign][exponent][significand].
+  using carrier_uint = typename info::carrier_uint;
+
+  constexpr auto num_float_significand_bits =
+      detail::num_significand_bits<Float>();
+
+  basic_fp<carrier_uint> f(value);
+  f.e += num_float_significand_bits;
+  if (!has_implicit_bit<Float>()) --f.e;
+
+  constexpr auto num_fraction_bits =
+      num_float_significand_bits + (has_implicit_bit<Float>() ? 1 : 0);
+  constexpr auto num_xdigits = (num_fraction_bits + 3) / 4;
+
+  constexpr auto leading_shift = ((num_xdigits - 1) * 4);
+  const auto leading_mask = carrier_uint(0xF) << leading_shift;
+  const auto leading_xdigit =
+      static_cast<uint32_t>((f.f & leading_mask) >> leading_shift);
+  if (leading_xdigit > 1) f.e -= (32 - countl_zero(leading_xdigit) - 1);
+
+  int print_xdigits = num_xdigits - 1;
+  if (precision >= 0 && print_xdigits > precision) {
+    const int shift = ((print_xdigits - precision - 1) * 4);
+    const auto mask = carrier_uint(0xF) << shift;
+    const auto v = static_cast<uint32_t>((f.f & mask) >> shift);
+
+    if (v >= 8) {
+      const auto inc = carrier_uint(1) << (shift + 4);
+      f.f += inc;
+      f.f &= ~(inc - 1);
+    }
+
+    // Check long double overflow
+    if (!has_implicit_bit<Float>()) {
+      const auto implicit_bit = carrier_uint(1) << num_float_significand_bits;
+      if ((f.f & implicit_bit) == implicit_bit) {
+        f.f >>= 4;
+        f.e += 4;
+      }
+    }
+
+    print_xdigits = precision;
+  }
+
+  char xdigits[num_bits<carrier_uint>() / 4];
+  detail::fill_n(xdigits, sizeof(xdigits), '0');
+  format_uint<4>(xdigits, f.f, num_xdigits, specs.upper);
+
+  // Remove zero tail
+  while (print_xdigits > 0 && xdigits[print_xdigits] == '0') --print_xdigits;
+
+  buf.push_back('0');
+  buf.push_back(specs.upper ? 'X' : 'x');
+  buf.push_back(xdigits[0]);
+  if (specs.showpoint || print_xdigits > 0 || print_xdigits < precision)
+    buf.push_back('.');
+  buf.append(xdigits + 1, xdigits + 1 + print_xdigits);
+  for (; print_xdigits < precision; ++print_xdigits) buf.push_back('0');
+
+  buf.push_back(specs.upper ? 'P' : 'p');
+
+  uint32_t abs_e;
+  if (f.e < 0) {
+    buf.push_back('-');
+    abs_e = static_cast<uint32_t>(-f.e);
+  } else {
+    buf.push_back('+');
+    abs_e = static_cast<uint32_t>(f.e);
+  }
+  format_decimal<char>(appender(buf), abs_e, detail::count_digits(abs_e));
+}
+
+template <typename Float, FMT_ENABLE_IF(is_double_double<Float>::value)>
+FMT_CONSTEXPR20 void format_hexfloat(Float value, int precision,
+                                     float_specs specs, buffer<char>& buf) {
+  format_hexfloat(static_cast<double>(value), precision, specs, buf);
+}
+
+template <typename Float>
+FMT_CONSTEXPR20 auto format_float(Float value, int precision, float_specs specs,
+                                  buffer<char>& buf) -> int {
+  // float is passed as double to reduce the number of instantiations.
+  static_assert(!std::is_same<Float, float>::value, "");
+  FMT_ASSERT(value >= 0, "value is negative");
+  auto converted_value = convert_float(value);
+
+  const bool fixed = specs.format == float_format::fixed;
+  if (value <= 0) {  // <= instead of == to silence a warning.
+    if (precision <= 0 || !fixed) {
+      buf.push_back('0');
+      return 0;
+    }
+    buf.try_resize(to_unsigned(precision));
+    fill_n(buf.data(), precision, '0');
+    return -precision;
+  }
+
+  int exp = 0;
+  bool use_dragon = true;
+  unsigned dragon_flags = 0;
+  if (!is_fast_float<Float>()) {
+    const auto inv_log2_10 = 0.3010299956639812;  // 1 / log2(10)
+    using info = dragonbox::float_info<decltype(converted_value)>;
+    const auto f = basic_fp<typename info::carrier_uint>(converted_value);
+    // Compute exp, an approximate power of 10, such that
+    //   10^(exp - 1) <= value < 10^exp or 10^exp <= value < 10^(exp + 1).
+    // This is based on log10(value) == log2(value) / log2(10) and approximation
+    // of log2(value) by e + num_fraction_bits idea from double-conversion.
+    exp = static_cast<int>(
+        std::ceil((f.e + count_digits<1>(f.f) - 1) * inv_log2_10 - 1e-10));
+    dragon_flags = dragon::fixup;
+  } else if (!is_constant_evaluated() && precision < 0) {
+    // Use Dragonbox for the shortest format.
+    if (specs.binary32) {
+      auto dec = dragonbox::to_decimal(static_cast<float>(value));
+      write<char>(buffer_appender<char>(buf), dec.significand);
+      return dec.exponent;
+    }
+    auto dec = dragonbox::to_decimal(static_cast<double>(value));
+    write<char>(buffer_appender<char>(buf), dec.significand);
+    return dec.exponent;
+  } else if (is_constant_evaluated()) {
+    // Use Grisu + Dragon4 for the given precision:
+    // https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf.
+    const int min_exp = -60;  // alpha in Grisu.
+    int cached_exp10 = 0;     // K in Grisu.
+    fp normalized = normalize(fp(converted_value));
+    const auto cached_pow = get_cached_power(
+        min_exp - (normalized.e + fp::num_significand_bits), cached_exp10);
+    normalized = normalized * cached_pow;
+    gen_digits_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
+    if (grisu_gen_digits(normalized, 1, exp, handler) != digits::error &&
+        !is_constant_evaluated()) {
+      exp += handler.exp10;
+      buf.try_resize(to_unsigned(handler.size));
+      use_dragon = false;
+    } else {
+      exp += handler.size - cached_exp10 - 1;
+      precision = handler.precision;
+    }
+  } else {
+    // Extract significand bits and exponent bits.
+    using info = dragonbox::float_info<double>;
+    auto br = bit_cast<uint64_t>(static_cast<double>(value));
+
+    const uint64_t significand_mask =
+        (static_cast<uint64_t>(1) << num_significand_bits<double>()) - 1;
+    uint64_t significand = (br & significand_mask);
+    int exponent = static_cast<int>((br & exponent_mask<double>()) >>
+                                    num_significand_bits<double>());
+
+    if (exponent != 0) {  // Check if normal.
+      exponent -= exponent_bias<double>() + num_significand_bits<double>();
+      significand |=
+          (static_cast<uint64_t>(1) << num_significand_bits<double>());
+      significand <<= 1;
+    } else {
+      // Normalize subnormal inputs.
+      FMT_ASSERT(significand != 0, "zeros should not appear hear");
+      int shift = countl_zero(significand);
+      FMT_ASSERT(shift >= num_bits<uint64_t>() - num_significand_bits<double>(),
+                 "");
+      shift -= (num_bits<uint64_t>() - num_significand_bits<double>() - 2);
+      exponent = (std::numeric_limits<double>::min_exponent -
+                  num_significand_bits<double>()) -
+                 shift;
+      significand <<= shift;
+    }
+
+    // Compute the first several nonzero decimal significand digits.
+    // We call the number we get the first segment.
+    const int k = info::kappa - dragonbox::floor_log10_pow2(exponent);
+    exp = -k;
+    const int beta = exponent + dragonbox::floor_log2_pow10(k);
+    uint64_t first_segment;
+    bool has_more_segments;
+    int digits_in_the_first_segment;
+    {
+      const auto r = dragonbox::umul192_upper128(
+          significand << beta, dragonbox::get_cached_power(k));
+      first_segment = r.high();
+      has_more_segments = r.low() != 0;
+
+      // The first segment can have 18 ~ 19 digits.
+      if (first_segment >= 1000000000000000000ULL) {
+        digits_in_the_first_segment = 19;
+      } else {
+        // When it is of 18-digits, we align it to 19-digits by adding a bogus
+        // zero at the end.
+        digits_in_the_first_segment = 18;
+        first_segment *= 10;
+      }
+    }
+
+    // Compute the actual number of decimal digits to print.
+    if (fixed) {
+      adjust_precision(precision, exp + digits_in_the_first_segment);
+    }
+
+    // Use Dragon4 only when there might be not enough digits in the first
+    // segment.
+    if (digits_in_the_first_segment > precision) {
+      use_dragon = false;
+
+      if (precision <= 0) {
+        exp += digits_in_the_first_segment;
+
+        if (precision < 0) {
+          // Nothing to do, since all we have are just leading zeros.
+          buf.try_resize(0);
+        } else {
+          // We may need to round-up.
+          buf.try_resize(1);
+          if ((first_segment | static_cast<uint64_t>(has_more_segments)) >
+              5000000000000000000ULL) {
+            buf[0] = '1';
+          } else {
+            buf[0] = '0';
+          }
+        }
+      }  // precision <= 0
+      else {
+        exp += digits_in_the_first_segment - precision;
+
+        // When precision > 0, we divide the first segment into three
+        // subsegments, each with 9, 9, and 0 ~ 1 digits so that each fits
+        // in 32-bits which usually allows faster calculation than in
+        // 64-bits. Since some compiler (e.g. MSVC) doesn't know how to optimize
+        // division-by-constant for large 64-bit divisors, we do it here
+        // manually. The magic number 7922816251426433760 below is equal to
+        // ceil(2^(64+32) / 10^10).
+        const uint32_t first_subsegment = static_cast<uint32_t>(
+            dragonbox::umul128_upper64(first_segment, 7922816251426433760ULL) >>
+            32);
+        const uint64_t second_third_subsegments =
+            first_segment - first_subsegment * 10000000000ULL;
+
+        uint64_t prod;
+        uint32_t digits;
+        bool should_round_up;
+        int number_of_digits_to_print = precision > 9 ? 9 : precision;
+
+        // Print a 9-digits subsegment, either the first or the second.
+        auto print_subsegment = [&](uint32_t subsegment, char* buffer) {
+          int number_of_digits_printed = 0;
+
+          // If we want to print an odd number of digits from the subsegment,
+          if ((number_of_digits_to_print & 1) != 0) {
+            // Convert to 64-bit fixed-point fractional form with 1-digit
+            // integer part. The magic number 720575941 is a good enough
+            // approximation of 2^(32 + 24) / 10^8; see
+            // https://jk-jeon.github.io/posts/2022/12/fixed-precision-formatting/#fixed-length-case
+            // for details.
+            prod = ((subsegment * static_cast<uint64_t>(720575941)) >> 24) + 1;
+            digits = static_cast<uint32_t>(prod >> 32);
+            *buffer = static_cast<char>('0' + digits);
+            number_of_digits_printed++;
+          }
+          // If we want to print an even number of digits from the
+          // first_subsegment,
+          else {
+            // Convert to 64-bit fixed-point fractional form with 2-digits
+            // integer part. The magic number 450359963 is a good enough
+            // approximation of 2^(32 + 20) / 10^7; see
+            // https://jk-jeon.github.io/posts/2022/12/fixed-precision-formatting/#fixed-length-case
+            // for details.
+            prod = ((subsegment * static_cast<uint64_t>(450359963)) >> 20) + 1;
+            digits = static_cast<uint32_t>(prod >> 32);
+            copy2(buffer, digits2(digits));
+            number_of_digits_printed += 2;
+          }
+
+          // Print all digit pairs.
+          while (number_of_digits_printed < number_of_digits_to_print) {
+            prod = static_cast<uint32_t>(prod) * static_cast<uint64_t>(100);
+            digits = static_cast<uint32_t>(prod >> 32);
+            copy2(buffer + number_of_digits_printed, digits2(digits));
+            number_of_digits_printed += 2;
+          }
+        };
+
+        // Print first subsegment.
+        print_subsegment(first_subsegment, buf.data());
+
+        // Perform rounding if the first subsegment is the last subsegment to
+        // print.
+        if (precision <= 9) {
+          // Rounding inside the subsegment.
+          // We round-up if:
+          //  - either the fractional part is strictly larger than 1/2, or
+          //  - the fractional part is exactly 1/2 and the last digit is odd.
+          // We rely on the following observations:
+          //  - If fractional_part >= threshold, then the fractional part is
+          //    strictly larger than 1/2.
+          //  - If the MSB of fractional_part is set, then the fractional part
+          //    must be at least 1/2.
+          //  - When the MSB of fractional_part is set, either
+          //    second_third_subsegments being nonzero or has_more_segments
+          //    being true means there are further digits not printed, so the
+          //    fractional part is strictly larger than 1/2.
+          if (precision < 9) {
+            uint32_t fractional_part = static_cast<uint32_t>(prod);
+            should_round_up = fractional_part >=
+                                  data::fractional_part_rounding_thresholds
+                                      [8 - number_of_digits_to_print] ||
+                              ((fractional_part >> 31) &
+                               ((digits & 1) | (second_third_subsegments != 0) |
+                                has_more_segments)) != 0;
+          }
+          // Rounding at the subsegment boundary.
+          // In this case, the fractional part is at least 1/2 if and only if
+          // second_third_subsegments >= 5000000000ULL, and is strictly larger
+          // than 1/2 if we further have either second_third_subsegments >
+          // 5000000000ULL or has_more_segments == true.
+          else {
+            should_round_up = second_third_subsegments > 5000000000ULL ||
+                              (second_third_subsegments == 5000000000ULL &&
+                               ((digits & 1) != 0 || has_more_segments));
+          }
+        }
+        // Otherwise, print the second subsegment.
+        else {
+          // Compilers are not aware of how to leverage the maximum value of
+          // second_third_subsegments to find out a better magic number which
+          // allows us to eliminate an additional shift. 1844674407370955162 =
+          // ceil(2^64/10) < ceil(2^64*(10^9/(10^10 - 1))).
+          const uint32_t second_subsegment =
+              static_cast<uint32_t>(dragonbox::umul128_upper64(
+                  second_third_subsegments, 1844674407370955162ULL));
+          const uint32_t third_subsegment =
+              static_cast<uint32_t>(second_third_subsegments) -
+              second_subsegment * 10;
+
+          number_of_digits_to_print = precision - 9;
+          print_subsegment(second_subsegment, buf.data() + 9);
+
+          // Rounding inside the subsegment.
+          if (precision < 18) {
+            // The condition third_subsegment != 0 implies that the segment was
+            // of 19 digits, so in this case the third segment should be
+            // consisting of a genuine digit from the input.
+            uint32_t fractional_part = static_cast<uint32_t>(prod);
+            should_round_up = fractional_part >=
+                                  data::fractional_part_rounding_thresholds
+                                      [8 - number_of_digits_to_print] ||
+                              ((fractional_part >> 31) &
+                               ((digits & 1) | (third_subsegment != 0) |
+                                has_more_segments)) != 0;
+          }
+          // Rounding at the subsegment boundary.
+          else {
+            // In this case, the segment must be of 19 digits, thus
+            // the third subsegment should be consisting of a genuine digit from
+            // the input.
+            should_round_up = third_subsegment > 5 ||
+                              (third_subsegment == 5 &&
+                               ((digits & 1) != 0 || has_more_segments));
+          }
+        }
+
+        // Round-up if necessary.
+        if (should_round_up) {
+          ++buf[precision - 1];
+          for (int i = precision - 1; i > 0 && buf[i] > '9'; --i) {
+            buf[i] = '0';
+            ++buf[i - 1];
+          }
+          if (buf[0] > '9') {
+            buf[0] = '1';
+            if (fixed)
+              buf[precision++] = '0';
+            else
+              ++exp;
+          }
+        }
+        buf.try_resize(to_unsigned(precision));
+      }
+    }  // if (digits_in_the_first_segment > precision)
+    else {
+      // Adjust the exponent for its use in Dragon4.
+      exp += digits_in_the_first_segment - 1;
+    }
+  }
+  if (use_dragon) {
+    auto f = basic_fp<uint128_t>();
+    bool is_predecessor_closer = specs.binary32
+                                     ? f.assign(static_cast<float>(value))
+                                     : f.assign(converted_value);
+    if (is_predecessor_closer) dragon_flags |= dragon::predecessor_closer;
+    if (fixed) dragon_flags |= dragon::fixed;
+    // Limit precision to the maximum possible number of significant digits in
+    // an IEEE754 double because we don't need to generate zeros.
+    const int max_double_digits = 767;
+    if (precision > max_double_digits) precision = max_double_digits;
+    format_dragon(f, dragon_flags, precision, buf, exp);
+  }
+  if (!fixed && !specs.showpoint) {
+    // Remove trailing zeros.
+    auto num_digits = buf.size();
+    while (num_digits > 0 && buf[num_digits - 1] == '0') {
+      --num_digits;
+      ++exp;
+    }
+    buf.try_resize(num_digits);
+  }
+  return exp;
+}
+template <typename Char, typename OutputIt, typename T>
+FMT_CONSTEXPR20 auto write_float(OutputIt out, T value,
+                                 format_specs<Char> specs, locale_ref loc)
     -> OutputIt {
-  if (const_check(!is_supported_floating_point(value))) return out;
   float_specs fspecs = parse_float_type_spec(specs);
   fspecs.sign = specs.sign;
   if (detail::signbit(value)) {  // value < 0 is false for NaN so use signbit.
@@ -1995,7 +3829,7 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value,
   }
 
   if (!detail::isfinite(value))
-    return write_nonfinite(out, detail::isinf(value), specs, fspecs);
+    return write_nonfinite(out, detail::isnan(value), specs, fspecs);
 
   if (specs.align == align::numeric && fspecs.sign) {
     auto it = reserve(out, 1);
@@ -2008,7 +3842,7 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value,
   memory_buffer buffer;
   if (fspecs.format == float_format::hex) {
     if (fspecs.sign) buffer.push_back(detail::sign<char>(fspecs.sign));
-    snprintf_float(promote_float(value), specs.precision, fspecs, buffer);
+    format_hexfloat(convert_float(value), specs.precision, fspecs, buffer);
     return write_bytes<align::right>(out, {buffer.data(), buffer.size()},
                                      specs);
   }
@@ -2020,53 +3854,59 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value,
       throw_format_error("number is too big");
     else
       ++precision;
+  } else if (fspecs.format != float_format::fixed && precision == 0) {
+    precision = 1;
   }
   if (const_check(std::is_same<T, float>())) fspecs.binary32 = true;
-  if (!is_fast_float<T>()) fspecs.fallback = true;
-  int exp = format_float(promote_float(value), precision, fspecs, buffer);
+  int exp = format_float(convert_float(value), precision, fspecs, buffer);
   fspecs.precision = precision;
-  auto fp = big_decimal_fp{buffer.data(), static_cast<int>(buffer.size()), exp};
-  return write_float(out, fp, specs, fspecs, loc);
+  auto f = big_decimal_fp{buffer.data(), static_cast<int>(buffer.size()), exp};
+  return write_float(out, f, specs, fspecs, loc);
+}
+
+template <typename Char, typename OutputIt, typename T,
+          FMT_ENABLE_IF(is_floating_point<T>::value)>
+FMT_CONSTEXPR20 auto write(OutputIt out, T value, format_specs<Char> specs,
+                           locale_ref loc = {}) -> OutputIt {
+  if (const_check(!is_supported_floating_point(value))) return out;
+  return specs.localized && write_loc(out, value, specs, loc)
+             ? out
+             : write_float(out, value, specs, loc);
 }
 
 template <typename Char, typename OutputIt, typename T,
           FMT_ENABLE_IF(is_fast_float<T>::value)>
 FMT_CONSTEXPR20 auto write(OutputIt out, T value) -> OutputIt {
-  if (is_constant_evaluated()) {
-    return write(out, value, basic_format_specs<Char>());
-  }
-
+  if (is_constant_evaluated()) return write(out, value, format_specs<Char>());
   if (const_check(!is_supported_floating_point(value))) return out;
 
-  using floaty = conditional_t<std::is_same<T, long double>::value, double, T>;
-  using uint = typename dragonbox::float_info<floaty>::carrier_uint;
-  auto bits = bit_cast<uint>(value);
-
   auto fspecs = float_specs();
   if (detail::signbit(value)) {
     fspecs.sign = sign::minus;
     value = -value;
   }
 
-  constexpr auto specs = basic_format_specs<Char>();
-  uint mask = exponent_mask<floaty>();
-  if ((bits & mask) == mask)
-    return write_nonfinite(out, std::isinf(value), specs, fspecs);
+  constexpr auto specs = format_specs<Char>();
+  using floaty = conditional_t<std::is_same<T, long double>::value, double, T>;
+  using floaty_uint = typename dragonbox::float_info<floaty>::carrier_uint;
+  floaty_uint mask = exponent_mask<floaty>();
+  if ((bit_cast<floaty_uint>(value) & mask) == mask)
+    return write_nonfinite(out, std::isnan(value), specs, fspecs);
 
   auto dec = dragonbox::to_decimal(static_cast<floaty>(value));
   return write_float(out, dec, specs, fspecs, {});
 }
 
 template <typename Char, typename OutputIt, typename T,
-          FMT_ENABLE_IF(std::is_floating_point<T>::value &&
+          FMT_ENABLE_IF(is_floating_point<T>::value &&
                         !is_fast_float<T>::value)>
 inline auto write(OutputIt out, T value) -> OutputIt {
-  return write(out, value, basic_format_specs<Char>());
+  return write(out, value, format_specs<Char>());
 }
 
 template <typename Char, typename OutputIt>
-auto write(OutputIt out, monostate, basic_format_specs<Char> = {},
-           locale_ref = {}) -> OutputIt {
+auto write(OutputIt out, monostate, format_specs<Char> = {}, locale_ref = {})
+    -> OutputIt {
   FMT_ASSERT(false, "");
   return out;
 }
@@ -2085,28 +3925,6 @@ constexpr auto write(OutputIt out, const T& value) -> OutputIt {
   return write<Char>(out, to_string_view(value));
 }
 
-template <typename Char, typename OutputIt, typename T,
-          FMT_ENABLE_IF(is_integral<T>::value &&
-                        !std::is_same<T, bool>::value &&
-                        !std::is_same<T, Char>::value)>
-FMT_CONSTEXPR auto write(OutputIt out, T value) -> OutputIt {
-  auto abs_value = static_cast<uint32_or_64_or_128_t<T>>(value);
-  bool negative = is_negative(value);
-  // Don't do -abs_value since it trips unsigned-integer-overflow sanitizer.
-  if (negative) abs_value = ~abs_value + 1;
-  int num_digits = count_digits(abs_value);
-  auto size = (negative ? 1 : 0) + static_cast<size_t>(num_digits);
-  auto it = reserve(out, size);
-  if (auto ptr = to_pointer<Char>(it, size)) {
-    if (negative) *ptr++ = static_cast<Char>('-');
-    format_decimal<Char>(ptr, abs_value, num_digits);
-    return out;
-  }
-  if (negative) *it++ = static_cast<Char>('-');
-  it = format_decimal<Char>(it, abs_value, num_digits).end;
-  return base_iterator(out, it);
-}
-
 // FMT_ENABLE_IF() condition separated to workaround an MSVC bug.
 template <
     typename Char, typename OutputIt, typename T,
@@ -2116,15 +3934,14 @@ template <
             type::custom_type,
     FMT_ENABLE_IF(check)>
 FMT_CONSTEXPR auto write(OutputIt out, T value) -> OutputIt {
-  return write<Char>(
-      out, static_cast<typename std::underlying_type<T>::type>(value));
+  return write<Char>(out, static_cast<underlying_t<T>>(value));
 }
 
 template <typename Char, typename OutputIt, typename T,
           FMT_ENABLE_IF(std::is_same<T, bool>::value)>
 FMT_CONSTEXPR auto write(OutputIt out, T value,
-                         const basic_format_specs<Char>& specs = {},
-                         locale_ref = {}) -> OutputIt {
+                         const format_specs<Char>& specs = {}, locale_ref = {})
+    -> OutputIt {
   return specs.type != presentation_type::none &&
                  specs.type != presentation_type::string
              ? write(out, value ? 1 : 0, specs, {})
@@ -2141,21 +3958,16 @@ FMT_CONSTEXPR auto write(OutputIt out, Char value) -> OutputIt {
 template <typename Char, typename OutputIt>
 FMT_CONSTEXPR_CHAR_TRAITS auto write(OutputIt out, const Char* value)
     -> OutputIt {
-  if (!value) {
-    throw_format_error("string pointer is null");
-  } else {
-    out = write(out, basic_string_view<Char>(value));
-  }
+  if (value) return write(out, basic_string_view<Char>(value));
+  throw_format_error("string pointer is null");
   return out;
 }
 
 template <typename Char, typename OutputIt, typename T,
           FMT_ENABLE_IF(std::is_same<T, void>::value)>
-auto write(OutputIt out, const T* value,
-           const basic_format_specs<Char>& specs = {}, locale_ref = {})
-    -> OutputIt {
-  check_pointer_type_spec(specs.type, error_handler());
-  return write_ptr<Char>(out, to_uintptr(value), &specs);
+auto write(OutputIt out, const T* value, const format_specs<Char>& specs = {},
+           locale_ref = {}) -> OutputIt {
+  return write_ptr<Char>(out, bit_cast<uintptr_t>(value), &specs);
 }
 
 // A write overload that handles implicit conversions.
@@ -2163,9 +3975,9 @@ template <typename Char, typename OutputIt, typename T,
           typename Context = basic_format_context<OutputIt, Char>>
 FMT_CONSTEXPR auto write(OutputIt out, const T& value) -> enable_if_t<
     std::is_class<T>::value && !is_string<T>::value &&
-        !std::is_same<T, Char>::value &&
-        !std::is_same<const T&,
-                      decltype(arg_mapper<Context>().map(value))>::value,
+        !is_floating_point<T>::value && !std::is_same<T, Char>::value &&
+        !std::is_same<T, remove_cvref_t<decltype(arg_mapper<Context>().map(
+                             value))>>::value,
     OutputIt> {
   return write<Char>(out, arg_mapper<Context>().map(value));
 }
@@ -2175,12 +3987,8 @@ template <typename Char, typename OutputIt, typename T,
 FMT_CONSTEXPR auto write(OutputIt out, const T& value)
     -> enable_if_t<mapped_type_constant<T, Context>::value == type::custom_type,
                    OutputIt> {
-  using formatter_type =
-      conditional_t<has_formatter<T, Context>::value,
-                    typename Context::template formatter_type<T>,
-                    fallback_formatter<T, Char>>;
   auto ctx = Context(out, {}, {});
-  return formatter_type().format(value, ctx);
+  return typename Context::template formatter_type<T>().format(value, ctx);
 }
 
 // An argument visitor that formats the argument and writes it via the output
@@ -2209,7 +4017,7 @@ template <typename Char> struct arg_formatter {
   using context = buffer_context<Char>;
 
   iterator out;
-  const basic_format_specs<Char>& specs;
+  const format_specs<Char>& specs;
   locale_ref locale;
 
   template <typename T>
@@ -2234,12 +4042,6 @@ template <typename Char> struct custom_formatter {
   template <typename T> void operator()(T) const {}
 };
 
-template <typename T>
-using is_integer =
-    bool_constant<is_integral<T>::value && !std::is_same<T, bool>::value &&
-                  !std::is_same<T, char>::value &&
-                  !std::is_same<T, wchar_t>::value>;
-
 template <typename ErrorHandler> class width_checker {
  public:
   explicit FMT_CONSTEXPR width_checker(ErrorHandler& eh) : handler_(eh) {}
@@ -2296,48 +4098,6 @@ FMT_CONSTEXPR auto get_arg(Context& ctx, ID id) ->
   return arg;
 }
 
-// The standard format specifier handler with checking.
-template <typename Char> class specs_handler : public specs_setter<Char> {
- private:
-  basic_format_parse_context<Char>& parse_context_;
-  buffer_context<Char>& context_;
-
-  // This is only needed for compatibility with gcc 4.4.
-  using format_arg = basic_format_arg<buffer_context<Char>>;
-
-  FMT_CONSTEXPR auto get_arg(auto_id) -> format_arg {
-    return detail::get_arg(context_, parse_context_.next_arg_id());
-  }
-
-  FMT_CONSTEXPR auto get_arg(int arg_id) -> format_arg {
-    parse_context_.check_arg_id(arg_id);
-    return detail::get_arg(context_, arg_id);
-  }
-
-  FMT_CONSTEXPR auto get_arg(basic_string_view<Char> arg_id) -> format_arg {
-    parse_context_.check_arg_id(arg_id);
-    return detail::get_arg(context_, arg_id);
-  }
-
- public:
-  FMT_CONSTEXPR specs_handler(basic_format_specs<Char>& specs,
-                              basic_format_parse_context<Char>& parse_ctx,
-                              buffer_context<Char>& ctx)
-      : specs_setter<Char>(specs), parse_context_(parse_ctx), context_(ctx) {}
-
-  template <typename Id> FMT_CONSTEXPR void on_dynamic_width(Id arg_id) {
-    this->specs_.width = get_dynamic_spec<width_checker>(
-        get_arg(arg_id), context_.error_handler());
-  }
-
-  template <typename Id> FMT_CONSTEXPR void on_dynamic_precision(Id arg_id) {
-    this->specs_.precision = get_dynamic_spec<precision_checker>(
-        get_arg(arg_id), context_.error_handler());
-  }
-
-  void on_error(const char* message) { context_.on_error(message); }
-};
-
 template <template <typename> class Handler, typename Context>
 FMT_CONSTEXPR void handle_dynamic_spec(int& value,
                                        arg_ref<typename Context::char_type> ref,
@@ -2346,53 +4106,27 @@ FMT_CONSTEXPR void handle_dynamic_spec(int& value,
   case arg_id_kind::none:
     break;
   case arg_id_kind::index:
-    value = detail::get_dynamic_spec<Handler>(ctx.arg(ref.val.index),
+    value = detail::get_dynamic_spec<Handler>(get_arg(ctx, ref.val.index),
                                               ctx.error_handler());
     break;
   case arg_id_kind::name:
-    value = detail::get_dynamic_spec<Handler>(ctx.arg(ref.val.name),
+    value = detail::get_dynamic_spec<Handler>(get_arg(ctx, ref.val.name),
                                               ctx.error_handler());
     break;
   }
 }
 
-#define FMT_STRING_IMPL(s, base, explicit)                                 \
-  [] {                                                                     \
-    /* Use the hidden visibility as a workaround for a GCC bug (#1973). */ \
-    /* Use a macro-like name to avoid shadowing warnings. */               \
-    struct FMT_GCC_VISIBILITY_HIDDEN FMT_COMPILE_STRING : base {           \
-      using char_type = fmt::remove_cvref_t<decltype(s[0])>;               \
-      FMT_MAYBE_UNUSED FMT_CONSTEXPR explicit                              \
-      operator fmt::basic_string_view<char_type>() const {                 \
-        return fmt::detail_exported::compile_string_to_view<char_type>(s); \
-      }                                                                    \
-    };                                                                     \
-    return FMT_COMPILE_STRING();                                           \
-  }()
-
-/**
-  \rst
-  Constructs a compile-time format string from a string literal *s*.
-
-  **Example**::
-
-    // A compile-time error because 'd' is an invalid specifier for strings.
-    std::string s = fmt::format(FMT_STRING("{:d}"), "foo");
-  \endrst
- */
-#define FMT_STRING(s) FMT_STRING_IMPL(s, fmt::compile_string, )
-
 #if FMT_USE_USER_DEFINED_LITERALS
 template <typename Char> struct udl_formatter {
   basic_string_view<Char> str;
 
   template <typename... T>
   auto operator()(T&&... args) const -> std::basic_string<Char> {
-    return vformat(str, fmt::make_args_checked<T...>(str, args...));
+    return vformat(str, fmt::make_format_args<buffer_context<Char>>(args...));
   }
 };
 
-#  if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
 template <typename T, typename Char, size_t N,
           fmt::detail_exported::fixed_string<Char, N> Str>
 struct statically_named_arg : view {
@@ -2430,21 +4164,21 @@ template <typename Char> struct udl_arg {
 #endif  // FMT_USE_USER_DEFINED_LITERALS
 
 template <typename Locale, typename Char>
-auto vformat(const Locale& loc, basic_string_view<Char> format_str,
+auto vformat(const Locale& loc, basic_string_view<Char> fmt,
              basic_format_args<buffer_context<type_identity_t<Char>>> args)
     -> std::basic_string<Char> {
-  basic_memory_buffer<Char> buffer;
-  detail::vformat_to(buffer, format_str, args, detail::locale_ref(loc));
-  return {buffer.data(), buffer.size()};
+  auto buf = basic_memory_buffer<Char>();
+  detail::vformat_to(buf, fmt, args, detail::locale_ref(loc));
+  return {buf.data(), buf.size()};
 }
 
 using format_func = void (*)(detail::buffer<char>&, int, const char*);
 
 FMT_API void format_error_code(buffer<char>& out, int error_code,
-                               string_view message) FMT_NOEXCEPT;
+                               string_view message) noexcept;
 
 FMT_API void report_error(format_func func, int error_code,
-                          const char* message) FMT_NOEXCEPT;
+                          const char* message) noexcept;
 FMT_END_DETAIL_NAMESPACE
 
 FMT_API auto vsystem_error(int error_code, string_view format_str,
@@ -2490,12 +4224,11 @@ auto system_error(int error_code, format_string<T...> fmt, T&&... args)
   \endrst
  */
 FMT_API void format_system_error(detail::buffer<char>& out, int error_code,
-                                 const char* message) FMT_NOEXCEPT;
+                                 const char* message) noexcept;
 
 // Reports a system error without throwing an exception.
 // Can be used to report errors from destructors.
-FMT_API void report_system_error(int error_code,
-                                 const char* message) FMT_NOEXCEPT;
+FMT_API void report_system_error(int error_code, const char* message) noexcept;
 
 /** Fast integer formatter. */
 class format_int {
@@ -2558,46 +4291,16 @@ class format_int {
 };
 
 template <typename T, typename Char>
-template <typename FormatContext>
-FMT_CONSTEXPR FMT_INLINE auto
-formatter<T, Char,
-          enable_if_t<detail::type_constant<T, Char>::value !=
-                      detail::type::custom_type>>::format(const T& val,
-                                                          FormatContext& ctx)
-    const -> decltype(ctx.out()) {
-  if (specs_.width_ref.kind != detail::arg_id_kind::none ||
-      specs_.precision_ref.kind != detail::arg_id_kind::none) {
-    auto specs = specs_;
-    detail::handle_dynamic_spec<detail::width_checker>(specs.width,
-                                                       specs.width_ref, ctx);
-    detail::handle_dynamic_spec<detail::precision_checker>(
-        specs.precision, specs.precision_ref, ctx);
-    return detail::write<Char>(ctx.out(), val, specs, ctx.locale());
-  }
-  return detail::write<Char>(ctx.out(), val, specs_, ctx.locale());
-}
+struct formatter<T, Char, enable_if_t<detail::has_format_as<T>::value>>
+    : private formatter<detail::format_as_t<T>> {
+  using base = formatter<detail::format_as_t<T>>;
+  using base::parse;
 
-#define FMT_FORMAT_AS(Type, Base)                                        \
-  template <typename Char>                                               \
-  struct formatter<Type, Char> : formatter<Base, Char> {                 \
-    template <typename FormatContext>                                    \
-    auto format(Type const& val, FormatContext& ctx) const               \
-        -> decltype(ctx.out()) {                                         \
-      return formatter<Base, Char>::format(static_cast<Base>(val), ctx); \
-    }                                                                    \
-  }
-
-FMT_FORMAT_AS(signed char, int);
-FMT_FORMAT_AS(unsigned char, unsigned);
-FMT_FORMAT_AS(short, int);
-FMT_FORMAT_AS(unsigned short, unsigned);
-FMT_FORMAT_AS(long, long long);
-FMT_FORMAT_AS(unsigned long, unsigned long long);
-FMT_FORMAT_AS(Char*, const Char*);
-FMT_FORMAT_AS(std::basic_string<Char>, basic_string_view<Char>);
-FMT_FORMAT_AS(std::nullptr_t, const void*);
-FMT_FORMAT_AS(detail::byte, unsigned char);
-FMT_FORMAT_AS(detail::std_string_view<Char>, basic_string_view<Char>);
+  template <typename FormatContext>
+  auto format(const T& value, FormatContext& ctx) const -> decltype(ctx.out()) {
+    return base::format(format_as(value), ctx);
+  }
+};
 
 template <typename Char>
 struct formatter<void*, Char> : formatter<const void*, Char> {
@@ -2616,58 +4319,6 @@ struct formatter<Char[N], Char> : formatter<basic_string_view<Char>, Char> {
   }
 };
 
-// A formatter for types known only at run time such as variant alternatives.
-//
-// Usage:
-//   using variant = std::variant<int, std::string>;
-//   template <>
-//   struct formatter<variant>: dynamic_formatter<> {
-//     auto format(const variant& v, format_context& ctx) {
-//       return visit([&](const auto& val) {
-//           return dynamic_formatter<>::format(val, ctx);
-//       }, v);
-//     }
-//   };
-template <typename Char = char> class dynamic_formatter {
- private:
-  detail::dynamic_format_specs<Char> specs_;
-  const Char* format_str_;
-
-  struct null_handler : detail::error_handler {
-    void on_align(align_t) {}
-    void on_sign(sign_t) {}
-    void on_hash() {}
-  };
-
-  template <typename Context> void handle_specs(Context& ctx) {
-    detail::handle_dynamic_spec<detail::width_checker>(specs_.width,
-                                                       specs_.width_ref, ctx);
-    detail::handle_dynamic_spec<detail::precision_checker>(
-        specs_.precision, specs_.precision_ref, ctx);
-  }
-
- public:
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    format_str_ = ctx.begin();
-    // Checks are deferred to formatting time when the argument type is known.
-    detail::dynamic_specs_handler<ParseContext> handler(specs_, ctx);
-    return detail::parse_format_specs(ctx.begin(), ctx.end(), handler);
-  }
-
-  template <typename T, typename FormatContext>
-  auto format(const T& val, FormatContext& ctx) -> decltype(ctx.out()) {
-    handle_specs(ctx);
-    detail::specs_checker<null_handler> checker(
-        null_handler(), detail::mapped_type_constant<T, FormatContext>::value);
-    checker.on_align(specs_.align);
-    if (specs_.sign != sign::none) checker.on_sign(specs_.sign);
-    if (specs_.alt) checker.on_hash();
-    if (specs_.precision >= 0) checker.end_precision();
-    return detail::write<Char>(ctx.out(), val, specs_, ctx.locale());
-  }
-};
-
 /**
   \rst
   Converts ``p`` to ``const void*`` for pointer formatting.
@@ -2681,13 +4332,36 @@ template <typename T> auto ptr(T p) -> const void* {
   static_assert(std::is_pointer<T>::value, "");
   return detail::bit_cast<const void*>(p);
 }
-template <typename T> auto ptr(const std::unique_ptr<T>& p) -> const void* {
+template <typename T, typename Deleter>
+auto ptr(const std::unique_ptr<T, Deleter>& p) -> const void* {
   return p.get();
 }
 template <typename T> auto ptr(const std::shared_ptr<T>& p) -> const void* {
   return p.get();
 }
 
+/**
+  \rst
+  Converts ``e`` to the underlying type.
+
+  **Example**::
+
+    enum class color { red, green, blue };
+    auto s = fmt::format("{}", fmt::underlying(color::red));
+  \endrst
+ */
+template <typename Enum>
+constexpr auto underlying(Enum e) noexcept -> underlying_t<Enum> {
+  return static_cast<underlying_t<Enum>>(e);
+}
+
+namespace enums {
+template <typename Enum, FMT_ENABLE_IF(std::is_enum<Enum>::value)>
+constexpr auto format_as(Enum e) noexcept -> underlying_t<Enum> {
+  return static_cast<underlying_t<Enum>>(e);
+}
+}  // namespace enums
+
 class bytes {
  private:
   string_view data_;
@@ -2699,17 +4373,13 @@ class bytes {
 
 template <> struct formatter<bytes> {
  private:
-  detail::dynamic_format_specs<char> specs_;
+  detail::dynamic_format_specs<> specs_;
 
  public:
   template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    using handler_type = detail::dynamic_specs_handler<ParseContext>;
-    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
-                                                detail::type::string_type);
-    auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
-    detail::check_string_type_spec(specs_.type, ctx.error_handler());
-    return it;
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> const char* {
+    return parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx,
+                              detail::type::string_type);
   }
 
   template <typename FormatContext>
@@ -2742,17 +4412,13 @@ template <typename T> auto group_digits(T value) -> group_digits_view<T> {
 
 template <typename T> struct formatter<group_digits_view<T>> : formatter<T> {
  private:
-  detail::dynamic_format_specs<char> specs_;
+  detail::dynamic_format_specs<> specs_;
 
  public:
   template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    using handler_type = detail::dynamic_specs_handler<ParseContext>;
-    detail::specs_checker<handler_type> handler(handler_type(specs_, ctx),
-                                                detail::type::int_type);
-    auto it = parse_format_specs(ctx.begin(), ctx.end(), handler);
-    detail::check_string_type_spec(specs_.type, ctx.error_handler());
-    return it;
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> const char* {
+    return parse_format_specs(ctx.begin(), ctx.end(), specs_, ctx,
+                              detail::type::int_type);
   }
 
   template <typename FormatContext>
@@ -2762,12 +4428,13 @@ template <typename T> struct formatter<group_digits_view<T>> : formatter<T> {
                                                        specs_.width_ref, ctx);
     detail::handle_dynamic_spec<detail::precision_checker>(
         specs_.precision, specs_.precision_ref, ctx);
-    return detail::write_int_localized(
+    return detail::write_int(
         ctx.out(), static_cast<detail::uint64_or_128_t<T>>(t.value), 0, specs_,
-        detail::digit_grouping<char>({"\3", ','}));
+        detail::digit_grouping<char>("\3", ","));
   }
 };
 
+// DEPRECATED! join_view will be moved to ranges.h.
 template <typename It, typename Sentinel, typename Char = char>
 struct join_view : detail::view {
   It begin;
@@ -2779,9 +4446,6 @@ struct join_view : detail::view {
 };
 
 template <typename It, typename Sentinel, typename Char>
-using arg_join FMT_DEPRECATED_ALIAS = join_view<It, Sentinel, Char>;
-
-template <typename It, typename Sentinel, typename Char>
 struct formatter<join_view<It, Sentinel, Char>, Char> {
  private:
   using value_type =
@@ -2790,45 +4454,26 @@ struct formatter<join_view<It, Sentinel, Char>, Char> {
 #else
       typename std::iterator_traits<It>::value_type;
 #endif
-  using context = buffer_context<Char>;
-  using mapper = detail::arg_mapper<context>;
-
-  template <typename T, FMT_ENABLE_IF(has_formatter<T, context>::value)>
-  static auto map(const T& value) -> const T& {
-    return value;
-  }
-  template <typename T, FMT_ENABLE_IF(!has_formatter<T, context>::value)>
-  static auto map(const T& value) -> decltype(mapper().map(value)) {
-    return mapper().map(value);
-  }
-
-  using formatter_type =
-      conditional_t<is_formattable<value_type, Char>::value,
-                    formatter<remove_cvref_t<decltype(map(
-                                  std::declval<const value_type&>()))>,
-                              Char>,
-                    detail::fallback_formatter<value_type, Char>>;
-
-  formatter_type value_formatter_;
+  formatter<remove_cvref_t<value_type>, Char> value_formatter_;
 
  public:
   template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> const Char* {
     return value_formatter_.parse(ctx);
   }
 
   template <typename FormatContext>
-  auto format(const join_view<It, Sentinel, Char>& value, FormatContext& ctx)
-      -> decltype(ctx.out()) {
+  auto format(const join_view<It, Sentinel, Char>& value,
+              FormatContext& ctx) const -> decltype(ctx.out()) {
     auto it = value.begin;
     auto out = ctx.out();
     if (it != value.end) {
-      out = value_formatter_.format(map(*it), ctx);
+      out = value_formatter_.format(*it, ctx);
       ++it;
       while (it != value.end) {
         out = detail::copy_str<Char>(value.sep.begin(), value.sep.end(), out);
         ctx.advance_to(out);
-        out = value_formatter_.format(map(*it), ctx);
+        out = value_formatter_.format(*it, ctx);
         ++it;
       }
     }
@@ -2880,9 +4525,9 @@ auto join(Range&& range, string_view sep)
  */
 template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
 inline auto to_string(const T& value) -> std::string {
-  auto result = std::string();
-  detail::write<char>(std::back_inserter(result), value);
-  return result;
+  auto buffer = memory_buffer();
+  detail::write<char>(appender(buffer), value);
+  return {buffer.data(), buffer.size()};
 }
 
 template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
@@ -2906,24 +4551,8 @@ FMT_NODISCARD auto to_string(const basic_memory_buffer<Char, SIZE>& buf)
 FMT_BEGIN_DETAIL_NAMESPACE
 
 template <typename Char>
-void vformat_to(
-    buffer<Char>& buf, basic_string_view<Char> fmt,
-    basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args,
-    locale_ref loc) {
-  // workaround for msvc bug regarding name-lookup in module
-  // link names into function scope
-  using detail::arg_formatter;
-  using detail::buffer_appender;
-  using detail::custom_formatter;
-  using detail::default_arg_formatter;
-  using detail::get_arg;
-  using detail::locale_ref;
-  using detail::parse_format_specs;
-  using detail::specs_checker;
-  using detail::specs_handler;
-  using detail::to_unsigned;
-  using detail::type;
-  using detail::write;
+void vformat_to(buffer<Char>& buf, basic_string_view<Char> fmt,
+                typename vformat_args<Char>::type args, locale_ref loc) {
   auto out = buffer_appender<Char>(buf);
   if (fmt.size() == 2 && equal2(fmt.data(), "{}")) {
     auto arg = args.get(0);
@@ -2936,9 +4565,10 @@ void vformat_to(
     basic_format_parse_context<Char> parse_context;
     buffer_context<Char> context;
 
-    format_handler(buffer_appender<Char> out, basic_string_view<Char> str,
-                   basic_format_args<buffer_context<Char>> args, locale_ref loc)
-        : parse_context(str), context(out, args, loc) {}
+    format_handler(buffer_appender<Char> p_out, basic_string_view<Char> str,
+                   basic_format_args<buffer_context<Char>> p_args,
+                   locale_ref p_loc)
+        : parse_context(str), context(p_out, p_args, p_loc) {}
 
     void on_text(const Char* begin, const Char* end) {
       auto text = basic_string_view<Char>(begin, to_unsigned(end - begin));
@@ -2969,15 +4599,16 @@ void vformat_to(
         -> const Char* {
       auto arg = get_arg(context, id);
       if (arg.type() == type::custom_type) {
-        parse_context.advance_to(parse_context.begin() +
-                                 (begin - &*parse_context.begin()));
+        parse_context.advance_to(begin);
         visit_format_arg(custom_formatter<Char>{parse_context, context}, arg);
         return parse_context.begin();
       }
-      auto specs = basic_format_specs<Char>();
-      specs_checker<specs_handler<Char>> handler(
-          specs_handler<Char>(specs, parse_context, context), arg.type());
-      begin = parse_format_specs(begin, end, handler);
+      auto specs = detail::dynamic_format_specs<Char>();
+      begin = parse_format_specs(begin, end, specs, parse_context, arg.type());
+      detail::handle_dynamic_spec<detail::width_checker>(
+          specs.width, specs.width_ref, context);
+      detail::handle_dynamic_spec<detail::precision_checker>(
+          specs.precision, specs.precision_ref, context);
       if (begin == end || *begin != '}')
         on_error("missing '}' in format string");
       auto f = arg_formatter<Char>{context.out(), specs, context.locale()};
@@ -2989,26 +4620,15 @@ void vformat_to(
 }
 
 #ifndef FMT_HEADER_ONLY
+extern template FMT_API void vformat_to(buffer<char>&, string_view,
+                                        typename vformat_args<>::type,
+                                        locale_ref);
 extern template FMT_API auto thousands_sep_impl<char>(locale_ref)
     -> thousands_sep_result<char>;
 extern template FMT_API auto thousands_sep_impl<wchar_t>(locale_ref)
     -> thousands_sep_result<wchar_t>;
 extern template FMT_API auto decimal_point_impl(locale_ref) -> char;
 extern template FMT_API auto decimal_point_impl(locale_ref) -> wchar_t;
-extern template auto format_float<double>(double value, int precision,
-                                          float_specs specs, buffer<char>& buf)
-    -> int;
-extern template auto format_float<long double>(long double value, int precision,
-                                               float_specs specs,
-                                               buffer<char>& buf) -> int;
-void snprintf_float(float, int, float_specs, buffer<char>&) = delete;
-extern template auto snprintf_float<double>(double value, int precision,
-                                            float_specs specs,
-                                            buffer<char>& buf) -> int;
-extern template auto snprintf_float<long double>(long double value,
-                                                 int precision,
-                                                 float_specs specs,
-                                                 buffer<char>& buf) -> int;
 #endif  // FMT_HEADER_ONLY
 
 FMT_END_DETAIL_NAMESPACE
@@ -3025,25 +4645,16 @@ inline namespace literals {
     fmt::print("Elapsed time: {s:.2f} seconds", "s"_a=1.23);
   \endrst
  */
-#  if FMT_USE_NONTYPE_TEMPLATE_PARAMETERS
-template <detail_exported::fixed_string Str>
-constexpr auto operator""_a()
-    -> detail::udl_arg<remove_cvref_t<decltype(Str.data[0])>,
-                       sizeof(Str.data) / sizeof(decltype(Str.data[0])), Str> {
-  return {};
+#  if FMT_USE_NONTYPE_TEMPLATE_ARGS
+template <detail_exported::fixed_string Str> constexpr auto operator""_a() {
+  using char_t = remove_cvref_t<decltype(Str.data[0])>;
+  return detail::udl_arg<char_t, sizeof(Str.data) / sizeof(char_t), Str>();
 }
 #  else
 constexpr auto operator"" _a(const char* s, size_t) -> detail::udl_arg<char> {
   return {s};
 }
 #  endif
-
-// DEPRECATED!
-// User-defined literal equivalent of fmt::format.
-FMT_DEPRECATED constexpr auto operator"" _format(const char* s, size_t n)
-    -> detail::udl_formatter<char> {
-  return {{s, n}};
-}
 }  // namespace literals
 #endif  // FMT_USE_USER_DEFINED_LITERALS
 
@@ -3057,15 +4668,7 @@ template <typename Locale, typename... T,
           FMT_ENABLE_IF(detail::is_locale<Locale>::value)>
 inline auto format(const Locale& loc, format_string<T...> fmt, T&&... args)
     -> std::string {
-  return vformat(loc, string_view(fmt), fmt::make_format_args(args...));
-}
-
-template <typename... T, size_t SIZE, typename Allocator>
-FMT_DEPRECATED auto format_to(basic_memory_buffer<char, SIZE, Allocator>& buf,
-                              format_string<T...> fmt, T&&... args)
-    -> appender {
-  detail::vformat_to(buf, string_view(fmt), fmt::make_format_args(args...));
-  return appender(buf);
+  return fmt::vformat(loc, string_view(fmt), fmt::make_format_args(args...));
 }
 
 template <typename OutputIt, typename Locale,
@@ -3076,7 +4679,7 @@ auto vformat_to(OutputIt out, const Locale& loc, string_view fmt,
   using detail::get_buffer;
   auto&& buf = get_buffer<char>(out);
   detail::vformat_to(buf, fmt, args, detail::locale_ref(loc));
-  return detail::get_iterator(buf);
+  return detail::get_iterator(buf, out);
 }
 
 template <typename OutputIt, typename Locale, typename... T,
@@ -3087,12 +4690,40 @@ FMT_INLINE auto format_to(OutputIt out, const Locale& loc,
   return vformat_to(out, loc, fmt, fmt::make_format_args(args...));
 }
 
-FMT_MODULE_EXPORT_END
-FMT_END_NAMESPACE
+template <typename Locale, typename... T,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value)>
+FMT_NODISCARD FMT_INLINE auto formatted_size(const Locale& loc,
+                                             format_string<T...> fmt,
+                                             T&&... args) -> size_t {
+  auto buf = detail::counting_buffer<>();
+  detail::vformat_to<char>(buf, fmt, fmt::make_format_args(args...),
+                           detail::locale_ref(loc));
+  return buf.count();
+}
 
-#ifdef FMT_DEPRECATED_INCLUDE_XCHAR
-#  include "xchar.h"
-#endif
+FMT_END_EXPORT
+
+template <typename T, typename Char>
+template <typename FormatContext>
+FMT_CONSTEXPR FMT_INLINE auto
+formatter<T, Char,
+          enable_if_t<detail::type_constant<T, Char>::value !=
+                      detail::type::custom_type>>::format(const T& val,
+                                                          FormatContext& ctx)
+    const -> decltype(ctx.out()) {
+  if (specs_.width_ref.kind != detail::arg_id_kind::none ||
+      specs_.precision_ref.kind != detail::arg_id_kind::none) {
+    auto specs = specs_;
+    detail::handle_dynamic_spec<detail::width_checker>(specs.width,
+                                                       specs.width_ref, ctx);
+    detail::handle_dynamic_spec<detail::precision_checker>(
+        specs.precision, specs.precision_ref, ctx);
+    return detail::write<Char>(ctx.out(), val, specs, ctx.locale());
+  }
+  return detail::write<Char>(ctx.out(), val, specs_, ctx.locale());
+}
+
+FMT_END_NAMESPACE
 
 #ifdef FMT_HEADER_ONLY
 #  define FMT_FUNC inline
diff --git a/contrib/fmt/include/fmt/os.h b/contrib/fmt/include/fmt/os.h
index b64f8bbfa..ec2904021 100644
--- a/contrib/fmt/include/fmt/os.h
+++ b/contrib/fmt/include/fmt/os.h
@@ -9,10 +9,8 @@
 #define FMT_OS_H_
 
 #include <cerrno>
-#include <clocale>  // locale_t
 #include <cstddef>
 #include <cstdio>
-#include <cstdlib>       // strtod_l
 #include <system_error>  // std::system_error
 
 #if defined __APPLE__ || defined(__FreeBSD__)
@@ -73,7 +71,7 @@
 #define FMT_RETRY(result, expression) FMT_RETRY_VAL(result, expression, -1)
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 /**
   \rst
@@ -122,50 +120,12 @@ template <typename Char> class basic_cstring_view {
 using cstring_view = basic_cstring_view<char>;
 using wcstring_view = basic_cstring_view<wchar_t>;
 
-template <typename Char> struct formatter<std::error_code, Char> {
-  template <typename ParseContext>
-  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
-  }
-
-  template <typename FormatContext>
-  FMT_CONSTEXPR auto format(const std::error_code& ec, FormatContext& ctx) const
-      -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    out = detail::write_bytes(out, ec.category().name(),
-                              basic_format_specs<Char>());
-    out = detail::write<Char>(out, Char(':'));
-    out = detail::write<Char>(out, ec.value());
-    return out;
-  }
-};
-
 #ifdef _WIN32
-FMT_API const std::error_category& system_category() FMT_NOEXCEPT;
+FMT_API const std::error_category& system_category() noexcept;
 
 FMT_BEGIN_DETAIL_NAMESPACE
-// A converter from UTF-16 to UTF-8.
-// It is only provided for Windows since other systems support UTF-8 natively.
-class utf16_to_utf8 {
- private:
-  memory_buffer buffer_;
-
- public:
-  utf16_to_utf8() {}
-  FMT_API explicit utf16_to_utf8(basic_string_view<wchar_t> s);
-  operator string_view() const { return string_view(&buffer_[0], size()); }
-  size_t size() const { return buffer_.size() - 1; }
-  const char* c_str() const { return &buffer_[0]; }
-  std::string str() const { return std::string(&buffer_[0], size()); }
-
-  // Performs conversion returning a system error code instead of
-  // throwing exception on conversion error. This method may still throw
-  // in case of memory allocation error.
-  FMT_API int convert(basic_string_view<wchar_t> s);
-};
-
 FMT_API void format_windows_error(buffer<char>& out, int error_code,
-                                  const char* message) FMT_NOEXCEPT;
+                                  const char* message) noexcept;
 FMT_END_DETAIL_NAMESPACE
 
 FMT_API std::system_error vwindows_error(int error_code, string_view format_str,
@@ -207,10 +167,9 @@ std::system_error windows_error(int error_code, string_view message,
 
 // Reports a Windows error without throwing an exception.
 // Can be used to report errors from destructors.
-FMT_API void report_windows_error(int error_code,
-                                  const char* message) FMT_NOEXCEPT;
+FMT_API void report_windows_error(int error_code, const char* message) noexcept;
 #else
-inline const std::error_category& system_category() FMT_NOEXCEPT {
+inline const std::error_category& system_category() noexcept {
   return std::system_category();
 }
 #endif  // _WIN32
@@ -237,13 +196,13 @@ class buffered_file {
   void operator=(const buffered_file&) = delete;
 
   // Constructs a buffered_file object which doesn't represent any file.
-  buffered_file() FMT_NOEXCEPT : file_(nullptr) {}
+  buffered_file() noexcept : file_(nullptr) {}
 
   // Destroys the object closing the file it represents if any.
-  FMT_API ~buffered_file() FMT_NOEXCEPT;
+  FMT_API ~buffered_file() noexcept;
 
  public:
-  buffered_file(buffered_file&& other) FMT_NOEXCEPT : file_(other.file_) {
+  buffered_file(buffered_file&& other) noexcept : file_(other.file_) {
     other.file_ = nullptr;
   }
 
@@ -261,11 +220,9 @@ class buffered_file {
   FMT_API void close();
 
   // Returns the pointer to a FILE object representing this file.
-  FILE* get() const FMT_NOEXCEPT { return file_; }
+  FILE* get() const noexcept { return file_; }
 
-  // We place parentheses around fileno to workaround a bug in some versions
-  // of MinGW that define fileno as a macro.
-  FMT_API int(fileno)() const;
+  FMT_API int descriptor() const;
 
   void vprint(string_view format_str, format_args args) {
     fmt::vprint(file_, format_str, args);
@@ -279,12 +236,12 @@ class buffered_file {
 
 #if FMT_USE_FCNTL
 // A file. Closed file is represented by a file object with descriptor -1.
-// Methods that are not declared with FMT_NOEXCEPT may throw
+// Methods that are not declared with noexcept may throw
 // fmt::system_error in case of failure. Note that some errors such as
 // closing the file multiple times will cause a crash on Windows rather
 // than an exception. You can get standard behavior by overriding the
 // invalid parameter handler with _set_invalid_parameter_handler.
-class file {
+class FMT_API file {
  private:
   int fd_;  // File descriptor.
 
@@ -303,16 +260,16 @@ class file {
   };
 
   // Constructs a file object which doesn't represent any file.
-  file() FMT_NOEXCEPT : fd_(-1) {}
+  file() noexcept : fd_(-1) {}
 
   // Opens a file and constructs a file object representing this file.
-  FMT_API file(cstring_view path, int oflag);
+  file(cstring_view path, int oflag);
 
  public:
   file(const file&) = delete;
   void operator=(const file&) = delete;
 
-  file(file&& other) FMT_NOEXCEPT : fd_(other.fd_) { other.fd_ = -1; }
+  file(file&& other) noexcept : fd_(other.fd_) { other.fd_ = -1; }
 
   // Move assignment is not noexcept because close may throw.
   file& operator=(file&& other) {
@@ -323,43 +280,49 @@ class file {
   }
 
   // Destroys the object closing the file it represents if any.
-  FMT_API ~file() FMT_NOEXCEPT;
+  ~file() noexcept;
 
   // Returns the file descriptor.
-  int descriptor() const FMT_NOEXCEPT { return fd_; }
+  int descriptor() const noexcept { return fd_; }
 
   // Closes the file.
-  FMT_API void close();
+  void close();
 
   // Returns the file size. The size has signed type for consistency with
   // stat::st_size.
-  FMT_API long long size() const;
+  long long size() const;
 
   // Attempts to read count bytes from the file into the specified buffer.
-  FMT_API size_t read(void* buffer, size_t count);
+  size_t read(void* buffer, size_t count);
 
   // Attempts to write count bytes from the specified buffer to the file.
-  FMT_API size_t write(const void* buffer, size_t count);
+  size_t write(const void* buffer, size_t count);
 
   // Duplicates a file descriptor with the dup function and returns
   // the duplicate as a file object.
-  FMT_API static file dup(int fd);
+  static file dup(int fd);
 
   // Makes fd be the copy of this file descriptor, closing fd first if
   // necessary.
-  FMT_API void dup2(int fd);
+  void dup2(int fd);
 
   // Makes fd be the copy of this file descriptor, closing fd first if
   // necessary.
-  FMT_API void dup2(int fd, std::error_code& ec) FMT_NOEXCEPT;
+  void dup2(int fd, std::error_code& ec) noexcept;
 
   // Creates a pipe setting up read_end and write_end file objects for reading
   // and writing respectively.
-  FMT_API static void pipe(file& read_end, file& write_end);
+  static void pipe(file& read_end, file& write_end);
 
   // Creates a buffered_file object associated with this file and detaches
   // this file object from the file.
-  FMT_API buffered_file fdopen(const char* mode);
+  buffered_file fdopen(const char* mode);
+
+#  if defined(_WIN32) && !defined(__MINGW32__)
+  // Opens a file and constructs a file object representing this file by
+  // wcstring_view filename. Windows only.
+  static file open_windows_file(wcstring_view path, int oflag);
+#  endif
 };
 
 // Returns the memory page size.
@@ -402,6 +365,28 @@ struct ostream_params {
 #  endif
 };
 
+class file_buffer final : public buffer<char> {
+  file file_;
+
+  FMT_API void grow(size_t) override;
+
+ public:
+  FMT_API file_buffer(cstring_view path, const ostream_params& params);
+  FMT_API file_buffer(file_buffer&& other);
+  FMT_API ~file_buffer();
+
+  void flush() {
+    if (size() == 0) return;
+    file_.write(data(), size() * sizeof(data()[0]));
+    clear();
+  }
+
+  void close() {
+    flush();
+    file_.close();
+  }
+};
+
 FMT_END_DETAIL_NAMESPACE
 
 // Added {} below to work around default constructor error known to
@@ -409,49 +394,32 @@ FMT_END_DETAIL_NAMESPACE
 constexpr detail::buffer_size buffer_size{};
 
 /** A fast output stream which is not thread-safe. */
-class FMT_API ostream final : private detail::buffer<char> {
+class FMT_API ostream {
  private:
-  file file_;
-
-  void grow(size_t) override;
+  FMT_MSC_WARNING(suppress : 4251)
+  detail::file_buffer buffer_;
 
   ostream(cstring_view path, const detail::ostream_params& params)
-      : file_(path, params.oflag) {
-    set(new char[params.buffer_size], params.buffer_size);
-  }
+      : buffer_(path, params) {}
 
  public:
-  ostream(ostream&& other)
-      : detail::buffer<char>(other.data(), other.size(), other.capacity()),
-        file_(std::move(other.file_)) {
-    other.clear();
-    other.set(nullptr, 0);
-  }
-  ~ostream() {
-    flush();
-    delete[] data();
-  }
+  ostream(ostream&& other) : buffer_(std::move(other.buffer_)) {}
 
-  void flush() {
-    if (size() == 0) return;
-    file_.write(data(), size());
-    clear();
-  }
+  ~ostream();
+
+  void flush() { buffer_.flush(); }
 
   template <typename... T>
   friend ostream output_file(cstring_view path, T... params);
 
-  void close() {
-    flush();
-    file_.close();
-  }
+  void close() { buffer_.close(); }
 
   /**
     Formats ``args`` according to specifications in ``fmt`` and writes the
     output to the file.
    */
   template <typename... T> void print(format_string<T...> fmt, T&&... args) {
-    vformat_to(detail::buffer_appender<char>(*this), fmt,
+    vformat_to(detail::buffer_appender<char>(buffer_), fmt,
                fmt::make_format_args(args...));
   }
 };
@@ -462,7 +430,7 @@ class FMT_API ostream final : private detail::buffer<char> {
 
   * ``<integer>``: Flags passed to `open
     <https://pubs.opengroup.org/onlinepubs/007904875/functions/open.html>`_
-    (``file::WRONLY | file::CREATE`` by default)
+    (``file::WRONLY | file::CREATE | file::TRUNC`` by default)
   * ``buffer_size=<integer>``: Output buffer size
 
   **Example**::
@@ -477,51 +445,7 @@ inline ostream output_file(cstring_view path, T... params) {
 }
 #endif  // FMT_USE_FCNTL
 
-#ifdef FMT_LOCALE
-// A "C" numeric locale.
-class locale {
- private:
-#  ifdef _WIN32
-  using locale_t = _locale_t;
-
-  static void freelocale(locale_t loc) { _free_locale(loc); }
-
-  static double strtod_l(const char* nptr, char** endptr, _locale_t loc) {
-    return _strtod_l(nptr, endptr, loc);
-  }
-#  endif
-
-  locale_t locale_;
-
- public:
-  using type = locale_t;
-  locale(const locale&) = delete;
-  void operator=(const locale&) = delete;
-
-  locale() {
-#  ifndef _WIN32
-    locale_ = FMT_SYSTEM(newlocale(LC_NUMERIC_MASK, "C", nullptr));
-#  else
-    locale_ = _create_locale(LC_NUMERIC, "C");
-#  endif
-    if (!locale_) FMT_THROW(system_error(errno, "cannot create locale"));
-  }
-  ~locale() { freelocale(locale_); }
-
-  type get() const { return locale_; }
-
-  // Converts string to floating-point number and advances str past the end
-  // of the parsed input.
-  FMT_DEPRECATED double strtod(const char*& str) const {
-    char* end = nullptr;
-    double result = strtod_l(str, &end, locale_);
-    str = end;
-    return result;
-  }
-};
-using Locale FMT_DEPRECATED_ALIAS = locale;
-#endif  // FMT_LOCALE
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_OS_H_
diff --git a/contrib/fmt/include/fmt/ostream.h b/contrib/fmt/include/fmt/ostream.h
index 3d716ece8..ce65909b9 100644
--- a/contrib/fmt/include/fmt/ostream.h
+++ b/contrib/fmt/include/fmt/ostream.h
@@ -8,47 +8,67 @@
 #ifndef FMT_OSTREAM_H_
 #define FMT_OSTREAM_H_
 
-#include <ostream>
+#include <fstream>  // std::filebuf
+
+#if defined(_WIN32) && defined(__GLIBCXX__)
+#  include <ext/stdio_filebuf.h>
+#  include <ext/stdio_sync_filebuf.h>
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+#  include <__std_stream>
+#endif
 
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
 
-template <typename OutputIt, typename Char> class basic_printf_context;
-
 namespace detail {
 
-// Checks if T has a user-defined operator<<.
-template <typename T, typename Char, typename Enable = void>
-class is_streamable {
- private:
-  template <typename U>
-  static auto test(int)
-      -> bool_constant<sizeof(std::declval<std::basic_ostream<Char>&>()
-                              << std::declval<U>()) != 0>;
-
-  template <typename> static auto test(...) -> std::false_type;
-
-  using result = decltype(test<T>(0));
-
- public:
-  is_streamable() = default;
-
-  static const bool value = result::value;
+// Generate a unique explicit instantion in every translation unit using a tag
+// type in an anonymous namespace.
+namespace {
+struct file_access_tag {};
+}  // namespace
+template <typename Tag, typename BufType, FILE* BufType::*FileMemberPtr>
+class file_access {
+  friend auto get_file(BufType& obj) -> FILE* { return obj.*FileMemberPtr; }
 };
 
-// Formatting of built-in types and arrays is intentionally disabled because
-// it's handled by standard (non-ostream) formatters.
-template <typename T, typename Char>
-struct is_streamable<
-    T, Char,
-    enable_if_t<
-        std::is_arithmetic<T>::value || std::is_array<T>::value ||
-        std::is_pointer<T>::value || std::is_same<T, char8_type>::value ||
-        std::is_same<T, std::basic_string<Char>>::value ||
-        std::is_same<T, std_string_view<Char>>::value ||
-        (std::is_convertible<T, int>::value && !std::is_enum<T>::value)>>
-    : std::false_type {};
+#if FMT_MSC_VERSION
+template class file_access<file_access_tag, std::filebuf,
+                           &std::filebuf::_Myfile>;
+auto get_file(std::filebuf&) -> FILE*;
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+template class file_access<file_access_tag, std::__stdoutbuf<char>,
+                           &std::__stdoutbuf<char>::__file_>;
+auto get_file(std::__stdoutbuf<char>&) -> FILE*;
+#endif
+
+inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data) {
+#if FMT_MSC_VERSION
+  if (auto* buf = dynamic_cast<std::filebuf*>(os.rdbuf()))
+    if (FILE* f = get_file(*buf)) return write_console(f, data);
+#elif defined(_WIN32) && defined(__GLIBCXX__)
+  auto* rdbuf = os.rdbuf();
+  FILE* c_file;
+  if (auto* sfbuf = dynamic_cast<__gnu_cxx::stdio_sync_filebuf<char>*>(rdbuf))
+    c_file = sfbuf->file();
+  else if (auto* fbuf = dynamic_cast<__gnu_cxx::stdio_filebuf<char>*>(rdbuf))
+    c_file = fbuf->file();
+  else
+    return false;
+  if (c_file) return write_console(c_file, data);
+#elif defined(_WIN32) && defined(_LIBCPP_VERSION)
+  if (auto* buf = dynamic_cast<std::__stdoutbuf<char>*>(os.rdbuf()))
+    if (FILE* f = get_file(*buf)) return write_console(f, data);
+#else
+  ignore_unused(os, data);
+#endif
+  return false;
+}
+inline bool write_ostream_unicode(std::wostream&,
+                                  fmt::basic_string_view<wchar_t>) {
+  return false;
+}
 
 // Write the content of buf to os.
 // It is a separate function rather than a part of vprint to simplify testing.
@@ -76,41 +96,72 @@ void format_value(buffer<Char>& buf, const T& value,
 #endif
   output << value;
   output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
-  buf.try_resize(buf.size());
 }
 
+template <typename T> struct streamed_view { const T& value; };
+
+}  // namespace detail
+
 // Formats an object of type T that has an overloaded ostream operator<<.
-template <typename T, typename Char>
-struct fallback_formatter<T, Char, enable_if_t<is_streamable<T, Char>::value>>
-    : private formatter<basic_string_view<Char>, Char> {
-  using formatter<basic_string_view<Char>, Char>::parse;
+template <typename Char>
+struct basic_ostream_formatter : formatter<basic_string_view<Char>, Char> {
+  void set_debug_format() = delete;
 
-  template <typename OutputIt>
-  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx)
+  template <typename T, typename OutputIt>
+  auto format(const T& value, basic_format_context<OutputIt, Char>& ctx) const
       -> OutputIt {
     auto buffer = basic_memory_buffer<Char>();
-    format_value(buffer, value, ctx.locale());
+    detail::format_value(buffer, value, ctx.locale());
     return formatter<basic_string_view<Char>, Char>::format(
         {buffer.data(), buffer.size()}, ctx);
   }
+};
+
+using ostream_formatter = basic_ostream_formatter<char>;
 
-  // DEPRECATED!
+template <typename T, typename Char>
+struct formatter<detail::streamed_view<T>, Char>
+    : basic_ostream_formatter<Char> {
   template <typename OutputIt>
-  auto format(const T& value, basic_printf_context<OutputIt, Char>& ctx)
-      -> OutputIt {
-    auto buffer = basic_memory_buffer<Char>();
-    format_value(buffer, value, ctx.locale());
-    return std::copy(buffer.begin(), buffer.end(), ctx.out());
+  auto format(detail::streamed_view<T> view,
+              basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
+    return basic_ostream_formatter<Char>::format(view.value, ctx);
   }
 };
+
+/**
+  \rst
+  Returns a view that formats `value` via an ostream ``operator<<``.
+
+  **Example**::
+
+    fmt::print("Current thread id: {}\n",
+               fmt::streamed(std::this_thread::get_id()));
+  \endrst
+ */
+template <typename T>
+auto streamed(const T& value) -> detail::streamed_view<T> {
+  return {value};
+}
+
+namespace detail {
+
+inline void vprint_directly(std::ostream& os, string_view format_str,
+                            format_args args) {
+  auto buffer = memory_buffer();
+  detail::vformat_to(buffer, format_str, args);
+  detail::write_buffer(os, buffer);
+}
+
 }  // namespace detail
 
-FMT_MODULE_EXPORT
-template <typename Char>
-void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
+FMT_MODULE_EXPORT template <typename Char>
+void vprint(std::basic_ostream<Char>& os,
+            basic_string_view<type_identity_t<Char>> format_str,
             basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   auto buffer = basic_memory_buffer<Char>();
   detail::vformat_to(buffer, format_str, args);
+  if (detail::write_ostream_unicode(os, {buffer.data(), buffer.size()})) return;
   detail::write_buffer(os, buffer);
 }
 
@@ -123,13 +174,36 @@ void vprint(std::basic_ostream<Char>& os, basic_string_view<Char> format_str,
     fmt::print(cerr, "Don't {}!", "panic");
   \endrst
  */
+FMT_MODULE_EXPORT template <typename... T>
+void print(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  const auto& vargs = fmt::make_format_args(args...);
+  if (detail::is_utf8())
+    vprint(os, fmt, vargs);
+  else
+    detail::vprint_directly(os, fmt, vargs);
+}
+
 FMT_MODULE_EXPORT
-template <typename S, typename... Args,
-          typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
-void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
-  vprint(os, to_string_view(format_str),
-         fmt::make_args_checked<Args...>(format_str, args...));
+template <typename... Args>
+void print(std::wostream& os,
+           basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
+           Args&&... args) {
+  vprint(os, fmt, fmt::make_format_args<buffer_context<wchar_t>>(args...));
 }
+
+FMT_MODULE_EXPORT template <typename... T>
+void println(std::ostream& os, format_string<T...> fmt, T&&... args) {
+  fmt::print(os, "{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+FMT_MODULE_EXPORT
+template <typename... Args>
+void println(std::wostream& os,
+             basic_format_string<wchar_t, type_identity_t<Args>...> fmt,
+             Args&&... args) {
+  print(os, L"{}\n", fmt::format(fmt, std::forward<Args>(args)...));
+}
+
 FMT_END_NAMESPACE
 
 #endif  // FMT_OSTREAM_H_
diff --git a/contrib/fmt/include/fmt/printf.h b/contrib/fmt/include/fmt/printf.h
index 19d550f6c..554715e9b 100644
--- a/contrib/fmt/include/fmt/printf.h
+++ b/contrib/fmt/include/fmt/printf.h
@@ -10,12 +10,11 @@
 
 #include <algorithm>  // std::max
 #include <limits>     // std::numeric_limits
-#include <ostream>
 
 #include "format.h"
 
 FMT_BEGIN_NAMESPACE
-FMT_MODULE_EXPORT_BEGIN
+FMT_BEGIN_EXPORT
 
 template <typename T> struct printf_formatter { printf_formatter() = delete; };
 
@@ -82,13 +81,13 @@ class printf_precision_handler {
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   int operator()(T value) {
     if (!int_checker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
-      FMT_THROW(format_error("number is too big"));
+      throw_format_error("number is too big");
     return (std::max)(static_cast<int>(value), 0);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
   int operator()(T) {
-    FMT_THROW(format_error("precision is not integer"));
+    throw_format_error("precision is not integer");
     return 0;
   }
 };
@@ -195,12 +194,10 @@ template <typename Char> struct get_cstring {
 // left alignment if it is negative.
 template <typename Char> class printf_width_handler {
  private:
-  using format_specs = basic_format_specs<Char>;
-
-  format_specs& specs_;
+  format_specs<Char>& specs_;
 
  public:
-  explicit printf_width_handler(format_specs& specs) : specs_(specs) {}
+  explicit printf_width_handler(format_specs<Char>& specs) : specs_(specs) {}
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   unsigned operator()(T value) {
@@ -210,24 +207,31 @@ template <typename Char> class printf_width_handler {
       width = 0 - width;
     }
     unsigned int_max = max_value<int>();
-    if (width > int_max) FMT_THROW(format_error("number is too big"));
+    if (width > int_max) throw_format_error("number is too big");
     return static_cast<unsigned>(width);
   }
 
   template <typename T, FMT_ENABLE_IF(!std::is_integral<T>::value)>
   unsigned operator()(T) {
-    FMT_THROW(format_error("width is not integer"));
+    throw_format_error("width is not integer");
     return 0;
   }
 };
 
+// Workaround for a bug with the XL compiler when initializing
+// printf_arg_formatter's base class.
+template <typename Char>
+auto make_arg_formatter(buffer_appender<Char> iter, format_specs<Char>& s)
+    -> arg_formatter<Char> {
+  return {iter, s, locale_ref()};
+}
+
 // The ``printf`` argument formatter.
 template <typename OutputIt, typename Char>
 class printf_arg_formatter : public arg_formatter<Char> {
  private:
   using base = arg_formatter<Char>;
   using context_type = basic_printf_context<OutputIt, Char>;
-  using format_specs = basic_format_specs<Char>;
 
   context_type& context_;
 
@@ -238,8 +242,8 @@ class printf_arg_formatter : public arg_formatter<Char> {
   }
 
  public:
-  printf_arg_formatter(OutputIt iter, format_specs& s, context_type& ctx)
-      : base{iter, s, locale_ref()}, context_(ctx) {}
+  printf_arg_formatter(OutputIt iter, format_specs<Char>& s, context_type& ctx)
+      : base(make_arg_formatter(iter, s)), context_(ctx) {}
 
   OutputIt operator()(monostate value) { return base::operator()(value); }
 
@@ -248,7 +252,7 @@ class printf_arg_formatter : public arg_formatter<Char> {
     // MSVC2013 fails to compile separate overloads for bool and Char so use
     // std::is_same instead.
     if (std::is_same<T, Char>::value) {
-      format_specs fmt_specs = this->specs;
+      format_specs<Char> fmt_specs = this->specs;
       if (fmt_specs.type != presentation_type::none &&
           fmt_specs.type != presentation_type::chr) {
         return (*this)(static_cast<int>(value));
@@ -301,8 +305,7 @@ class printf_arg_formatter : public arg_formatter<Char> {
 };
 
 template <typename Char>
-void parse_flags(basic_format_specs<Char>& specs, const Char*& it,
-                 const Char* end) {
+void parse_flags(format_specs<Char>& specs, const Char*& it, const Char* end) {
   for (; it != end; ++it) {
     switch (*it) {
     case '-':
@@ -329,8 +332,8 @@ void parse_flags(basic_format_specs<Char>& specs, const Char*& it,
 }
 
 template <typename Char, typename GetArg>
-int parse_header(const Char*& it, const Char* end,
-                 basic_format_specs<Char>& specs, GetArg get_arg) {
+int parse_header(const Char*& it, const Char* end, format_specs<Char>& specs,
+                 GetArg get_arg) {
   int arg_index = -1;
   Char c = *it;
   if (c >= '0' && c <= '9') {
@@ -345,7 +348,7 @@ int parse_header(const Char*& it, const Char* end,
       if (value != 0) {
         // Nonzero value means that we parsed width and don't need to
         // parse it or flags again, so return now.
-        if (value == -1) FMT_THROW(format_error("number is too big"));
+        if (value == -1) throw_format_error("number is too big");
         specs.width = value;
         return arg_index;
       }
@@ -356,7 +359,7 @@ int parse_header(const Char*& it, const Char* end,
   if (it != end) {
     if (*it >= '0' && *it <= '9') {
       specs.width = parse_nonnegative_int(it, end, -1);
-      if (specs.width == -1) FMT_THROW(format_error("number is too big"));
+      if (specs.width == -1) throw_format_error("number is too big");
     } else if (*it == '*') {
       ++it;
       specs.width = static_cast<int>(visit_format_arg(
@@ -366,12 +369,52 @@ int parse_header(const Char*& it, const Char* end,
   return arg_index;
 }
 
+inline auto parse_printf_presentation_type(char c, type t)
+    -> presentation_type {
+  using pt = presentation_type;
+  constexpr auto integral_set = sint_set | uint_set | bool_set | char_set;
+  switch (c) {
+  case 'd':
+    return in(t, integral_set) ? pt::dec : pt::none;
+  case 'o':
+    return in(t, integral_set) ? pt::oct : pt::none;
+  case 'x':
+    return in(t, integral_set) ? pt::hex_lower : pt::none;
+  case 'X':
+    return in(t, integral_set) ? pt::hex_upper : pt::none;
+  case 'a':
+    return in(t, float_set) ? pt::hexfloat_lower : pt::none;
+  case 'A':
+    return in(t, float_set) ? pt::hexfloat_upper : pt::none;
+  case 'e':
+    return in(t, float_set) ? pt::exp_lower : pt::none;
+  case 'E':
+    return in(t, float_set) ? pt::exp_upper : pt::none;
+  case 'f':
+    return in(t, float_set) ? pt::fixed_lower : pt::none;
+  case 'F':
+    return in(t, float_set) ? pt::fixed_upper : pt::none;
+  case 'g':
+    return in(t, float_set) ? pt::general_lower : pt::none;
+  case 'G':
+    return in(t, float_set) ? pt::general_upper : pt::none;
+  case 'c':
+    return in(t, integral_set) ? pt::chr : pt::none;
+  case 's':
+    return in(t, string_set | cstring_set) ? pt::string : pt::none;
+  case 'p':
+    return in(t, pointer_set | cstring_set) ? pt::pointer : pt::none;
+  default:
+    return pt::none;
+  }
+}
+
 template <typename Char, typename Context>
 void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
              basic_format_args<Context> args) {
-  using OutputIt = buffer_appender<Char>;
-  auto out = OutputIt(buf);
-  auto context = basic_printf_context<OutputIt, Char>(out, args);
+  using iterator = buffer_appender<Char>;
+  auto out = iterator(buf);
+  auto context = basic_printf_context<iterator, Char>(out, args);
   auto parse_ctx = basic_printf_parse_context<Char>(format);
 
   // Returns the argument with specified index or, if arg_index is -1, the next
@@ -388,26 +431,25 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
   const Char* end = parse_ctx.end();
   auto it = start;
   while (it != end) {
-    if (!detail::find<false, Char>(it, end, '%', it)) {
-      it = end;  // detail::find leaves it == nullptr if it doesn't find '%'
+    if (!find<false, Char>(it, end, '%', it)) {
+      it = end;  // find leaves it == nullptr if it doesn't find '%'.
       break;
     }
     Char c = *it++;
     if (it != end && *it == c) {
-      out = detail::write(
-          out, basic_string_view<Char>(start, detail::to_unsigned(it - start)));
+      out = write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
       start = ++it;
       continue;
     }
-    out = detail::write(out, basic_string_view<Char>(
-                                 start, detail::to_unsigned(it - 1 - start)));
+    out =
+        write(out, basic_string_view<Char>(start, to_unsigned(it - 1 - start)));
 
-    basic_format_specs<Char> specs;
+    auto specs = format_specs<Char>();
     specs.align = align::right;
 
     // Parse argument index, flags and width.
     int arg_index = parse_header(it, end, specs, get_arg);
-    if (arg_index == 0) parse_ctx.on_error("argument not found");
+    if (arg_index == 0) throw_format_error("argument not found");
 
     // Parse precision.
     if (it != end && *it == '.') {
@@ -418,7 +460,7 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
       } else if (c == '*') {
         ++it;
         specs.precision = static_cast<int>(
-            visit_format_arg(detail::printf_precision_handler(), get_arg(-1)));
+            visit_format_arg(printf_precision_handler(), get_arg(-1)));
       } else {
         specs.precision = 0;
       }
@@ -430,17 +472,15 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     if (specs.precision >= 0 && arg.is_integral())
       specs.fill[0] =
           ' ';  // Ignore '0' flag for non-numeric types or if '-' present.
-    if (specs.precision >= 0 && arg.type() == detail::type::cstring_type) {
-      auto str = visit_format_arg(detail::get_cstring<Char>(), arg);
+    if (specs.precision >= 0 && arg.type() == type::cstring_type) {
+      auto str = visit_format_arg(get_cstring<Char>(), arg);
       auto str_end = str + specs.precision;
       auto nul = std::find(str, str_end, Char());
-      arg = detail::make_arg<basic_printf_context<OutputIt, Char>>(
+      arg = make_arg<basic_printf_context<iterator, Char>>(
           basic_string_view<Char>(
-              str, detail::to_unsigned(nul != str_end ? nul - str
-                                                      : specs.precision)));
+              str, to_unsigned(nul != str_end ? nul - str : specs.precision)));
     }
-    if (specs.alt && visit_format_arg(detail::is_zero_int(), arg))
-      specs.alt = false;
+    if (specs.alt && visit_format_arg(is_zero_int(), arg)) specs.alt = false;
     if (specs.fill[0] == '0') {
       if (arg.is_arithmetic() && specs.align != align::left)
         specs.align = align::numeric;
@@ -452,7 +492,6 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     // Parse length and convert the argument to the required type.
     c = it != end ? *it++ : 0;
     Char t = it != end ? *it : 0;
-    using detail::convert_arg;
     switch (c) {
     case 'h':
       if (t == 'h') {
@@ -491,7 +530,7 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
     }
 
     // Parse type.
-    if (it == end) FMT_THROW(format_error("invalid format string"));
+    if (it == end) throw_format_error("invalid format string");
     char type = static_cast<char>(*it++);
     if (arg.is_integral()) {
       // Normalize type.
@@ -502,22 +541,21 @@ void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
         break;
       case 'c':
         visit_format_arg(
-            detail::char_converter<basic_printf_context<OutputIt, Char>>(arg),
-            arg);
+            char_converter<basic_printf_context<iterator, Char>>(arg), arg);
         break;
       }
     }
-    specs.type = parse_presentation_type(type);
+    specs.type = parse_printf_presentation_type(type, arg.type());
     if (specs.type == presentation_type::none)
-      parse_ctx.on_error("invalid type specifier");
+      throw_format_error("invalid format specifier");
 
     start = it;
 
     // Format argument.
     out = visit_format_arg(
-        detail::printf_arg_formatter<OutputIt, Char>(out, specs, context), arg);
+        printf_arg_formatter<iterator, Char>(out, specs, context), arg);
   }
-  detail::write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
+  write(out, basic_string_view<Char>(start, to_unsigned(it - start)));
 }
 FMT_END_DETAIL_NAMESPACE
 
@@ -560,9 +598,9 @@ inline auto vsprintf(
     const S& fmt,
     basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
     -> std::basic_string<Char> {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(fmt), args);
-  return to_string(buffer);
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, detail::to_string_view(fmt), args);
+  return to_string(buf);
 }
 
 /**
@@ -578,7 +616,8 @@ template <typename S, typename... T,
           typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
 inline auto sprintf(const S& fmt, const T&... args) -> std::basic_string<Char> {
   using context = basic_printf_context_t<Char>;
-  return vsprintf(to_string_view(fmt), fmt::make_format_args<context>(args...));
+  return vsprintf(detail::to_string_view(fmt),
+                  fmt::make_format_args<context>(args...));
 }
 
 template <typename S, typename Char = char_t<S>>
@@ -586,10 +625,10 @@ inline auto vfprintf(
     std::FILE* f, const S& fmt,
     basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
     -> int {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(fmt), args);
-  size_t size = buffer.size();
-  return std::fwrite(buffer.data(), sizeof(Char), size, f) < size
+  auto buf = basic_memory_buffer<Char>();
+  detail::vprintf(buf, detail::to_string_view(fmt), args);
+  size_t size = buf.size();
+  return std::fwrite(buf.data(), sizeof(Char), size, f) < size
              ? -1
              : static_cast<int>(size);
 }
@@ -606,7 +645,7 @@ inline auto vfprintf(
 template <typename S, typename... T, typename Char = char_t<S>>
 inline auto fprintf(std::FILE* f, const S& fmt, const T&... args) -> int {
   using context = basic_printf_context_t<Char>;
-  return vfprintf(f, to_string_view(fmt),
+  return vfprintf(f, detail::to_string_view(fmt),
                   fmt::make_format_args<context>(args...));
 }
 
@@ -615,7 +654,7 @@ inline auto vprintf(
     const S& fmt,
     basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
     -> int {
-  return vfprintf(stdout, to_string_view(fmt), args);
+  return vfprintf(stdout, detail::to_string_view(fmt), args);
 }
 
 /**
@@ -630,28 +669,11 @@ inline auto vprintf(
 template <typename S, typename... T, FMT_ENABLE_IF(detail::is_string<S>::value)>
 inline auto printf(const S& fmt, const T&... args) -> int {
   return vprintf(
-      to_string_view(fmt),
+      detail::to_string_view(fmt),
       fmt::make_format_args<basic_printf_context_t<char_t<S>>>(args...));
 }
 
-template <typename S, typename Char = char_t<S>>
-FMT_DEPRECATED auto vfprintf(
-    std::basic_ostream<Char>& os, const S& fmt,
-    basic_format_args<basic_printf_context_t<type_identity_t<Char>>> args)
-    -> int {
-  basic_memory_buffer<Char> buffer;
-  vprintf(buffer, to_string_view(fmt), args);
-  os.write(buffer.data(), static_cast<std::streamsize>(buffer.size()));
-  return static_cast<int>(buffer.size());
-}
-template <typename S, typename... T, typename Char = char_t<S>>
-FMT_DEPRECATED auto fprintf(std::basic_ostream<Char>& os, const S& fmt,
-                            const T&... args) -> int {
-  return vfprintf(os, to_string_view(fmt),
-                  fmt::make_format_args<basic_printf_context_t<Char>>(args...));
-}
-
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_PRINTF_H_
diff --git a/contrib/fmt/include/fmt/ranges.h b/contrib/fmt/include/fmt/ranges.h
index eb9fb8a92..266b9e1b9 100644
--- a/contrib/fmt/include/fmt/ranges.h
+++ b/contrib/fmt/include/fmt/ranges.h
@@ -22,27 +22,25 @@ FMT_BEGIN_NAMESPACE
 
 namespace detail {
 
-template <typename RangeT, typename OutputIterator>
-OutputIterator copy(const RangeT& range, OutputIterator out) {
+template <typename Range, typename OutputIt>
+auto copy(const Range& range, OutputIt out) -> OutputIt {
   for (auto it = range.begin(), end = range.end(); it != end; ++it)
     *out++ = *it;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(const char* str, OutputIterator out) {
+template <typename OutputIt>
+auto copy(const char* str, OutputIt out) -> OutputIt {
   while (*str) *out++ = *str++;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(char ch, OutputIterator out) {
+template <typename OutputIt> auto copy(char ch, OutputIt out) -> OutputIt {
   *out++ = ch;
   return out;
 }
 
-template <typename OutputIterator>
-OutputIterator copy(wchar_t ch, OutputIterator out) {
+template <typename OutputIt> auto copy(wchar_t ch, OutputIt out) -> OutputIt {
   *out++ = ch;
   return out;
 }
@@ -55,7 +53,7 @@ template <typename T> class is_std_string_like {
   template <typename> static void check(...);
 
  public:
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       is_string<T>::value ||
       std::is_convertible<T, std_string_view<char>>::value ||
       !std::is_void<decltype(check<T>(nullptr))>::value;
@@ -69,10 +67,10 @@ template <typename T> class is_map {
   template <typename> static void check(...);
 
  public:
-#ifdef FMT_FORMAT_MAP_AS_LIST
-  static FMT_CONSTEXPR_DECL const bool value = false;
+#ifdef FMT_FORMAT_MAP_AS_LIST  // DEPRECATED!
+  static constexpr const bool value = false;
 #else
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       !std::is_void<decltype(check<T>(nullptr))>::value;
 #endif
 };
@@ -82,10 +80,10 @@ template <typename T> class is_set {
   template <typename> static void check(...);
 
  public:
-#ifdef FMT_FORMAT_SET_AS_LIST
-  static FMT_CONSTEXPR_DECL const bool value = false;
+#ifdef FMT_FORMAT_SET_AS_LIST  // DEPRECATED!
+  static constexpr const bool value = false;
 #else
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       !std::is_void<decltype(check<T>(nullptr))>::value && !is_map<T>::value;
 #endif
 };
@@ -94,7 +92,7 @@ template <typename... Ts> struct conditional_helper {};
 
 template <typename T, typename _ = void> struct is_range_ : std::false_type {};
 
-#if !FMT_MSC_VER || FMT_MSC_VER > 1800
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION > 1800
 
 #  define FMT_DECLTYPE_RETURN(val)  \
     ->decltype(val) { return val; } \
@@ -157,8 +155,9 @@ template <typename T>
 struct has_mutable_begin_end<
     T, void_t<decltype(detail::range_begin(std::declval<T>())),
               decltype(detail::range_end(std::declval<T>())),
-              enable_if_t<std::is_copy_constructible<T>::value>>>
-    : std::true_type {};
+              // the extra int here is because older versions of MSVC don't
+              // SFINAE properly unless there are distinct types
+              int>> : std::true_type {};
 
 template <typename T>
 struct is_range_<T, void>
@@ -174,12 +173,12 @@ template <typename T> class is_tuple_like_ {
   template <typename> static void check(...);
 
  public:
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       !std::is_void<decltype(check<T>(nullptr))>::value;
 };
 
 // Check for integer_sequence
-#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
+#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VERSION >= 1900
 template <typename T, T... N>
 using integer_sequence = std::integer_sequence<T, N...>;
 template <size_t... N> using index_sequence = std::index_sequence<N...>;
@@ -202,467 +201,375 @@ template <size_t N>
 using make_index_sequence = make_integer_sequence<size_t, N>;
 #endif
 
-template <class Tuple, class F, size_t... Is>
-void for_each(index_sequence<Is...>, Tuple&& tup, F&& f) FMT_NOEXCEPT {
-  using std::get;
-  // using free function get<I>(T) now.
-  const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
-  (void)_;  // blocks warnings
-}
-
-template <class T>
-FMT_CONSTEXPR make_index_sequence<std::tuple_size<T>::value> get_indexes(
-    T const&) {
-  return {};
-}
-
-template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
-  const auto indexes = get_indexes(tup);
-  for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
-}
-
-template <typename Range>
-using value_type =
-    remove_cvref_t<decltype(*detail::range_begin(std::declval<Range>()))>;
+template <typename T>
+using tuple_index_sequence = make_index_sequence<std::tuple_size<T>::value>;
 
-template <typename OutputIt> OutputIt write_delimiter(OutputIt out) {
-  *out++ = ',';
-  *out++ = ' ';
-  return out;
-}
+template <typename T, typename C, bool = is_tuple_like_<T>::value>
+class is_tuple_formattable_ {
+ public:
+  static constexpr const bool value = false;
+};
+template <typename T, typename C> class is_tuple_formattable_<T, C, true> {
+  template <std::size_t... Is>
+  static std::true_type check2(index_sequence<Is...>,
+                               integer_sequence<bool, (Is == Is)...>);
+  static std::false_type check2(...);
+  template <std::size_t... Is>
+  static decltype(check2(
+      index_sequence<Is...>{},
+      integer_sequence<
+          bool, (is_formattable<typename std::tuple_element<Is, T>::type,
+                                C>::value)...>{})) check(index_sequence<Is...>);
 
-struct singleton {
-  unsigned char upper;
-  unsigned char lower_count;
+ public:
+  static constexpr const bool value =
+      decltype(check(tuple_index_sequence<T>{}))::value;
 };
 
-inline auto is_printable(uint16_t x, const singleton* singletons,
-                         size_t singletons_size,
-                         const unsigned char* singleton_lowers,
-                         const unsigned char* normal, size_t normal_size)
-    -> bool {
-  auto upper = x >> 8;
-  auto lower_start = 0;
-  for (size_t i = 0; i < singletons_size; ++i) {
-    auto s = singletons[i];
-    auto lower_end = lower_start + s.lower_count;
-    if (upper < s.upper) break;
-    if (upper == s.upper) {
-      for (auto j = lower_start; j < lower_end; ++j) {
-        if (singleton_lowers[j] == (x & 0xff)) return false;
-      }
-    }
-    lower_start = lower_end;
-  }
+template <typename Tuple, typename F, size_t... Is>
+FMT_CONSTEXPR void for_each(index_sequence<Is...>, Tuple&& t, F&& f) {
+  using std::get;
+  // Using a free function get<Is>(Tuple) now.
+  const int unused[] = {0, ((void)f(get<Is>(t)), 0)...};
+  ignore_unused(unused);
+}
 
-  auto xsigned = static_cast<int>(x);
-  auto current = true;
-  for (size_t i = 0; i < normal_size; ++i) {
-    auto v = static_cast<int>(normal[i]);
-    auto len = (v & 0x80) != 0 ? (v & 0x7f) << 8 | normal[++i] : v;
-    xsigned -= len;
-    if (xsigned < 0) break;
-    current = !current;
-  }
-  return current;
+template <typename Tuple, typename F>
+FMT_CONSTEXPR void for_each(Tuple&& t, F&& f) {
+  for_each(tuple_index_sequence<remove_cvref_t<Tuple>>(),
+           std::forward<Tuple>(t), std::forward<F>(f));
 }
 
-// Returns true iff the code point cp is printable.
-// This code is generated by support/printable.py.
-inline auto is_printable(uint32_t cp) -> bool {
-  static constexpr singleton singletons0[] = {
-      {0x00, 1},  {0x03, 5},  {0x05, 6},  {0x06, 3},  {0x07, 6},  {0x08, 8},
-      {0x09, 17}, {0x0a, 28}, {0x0b, 25}, {0x0c, 20}, {0x0d, 16}, {0x0e, 13},
-      {0x0f, 4},  {0x10, 3},  {0x12, 18}, {0x13, 9},  {0x16, 1},  {0x17, 5},
-      {0x18, 2},  {0x19, 3},  {0x1a, 7},  {0x1c, 2},  {0x1d, 1},  {0x1f, 22},
-      {0x20, 3},  {0x2b, 3},  {0x2c, 2},  {0x2d, 11}, {0x2e, 1},  {0x30, 3},
-      {0x31, 2},  {0x32, 1},  {0xa7, 2},  {0xa9, 2},  {0xaa, 4},  {0xab, 8},
-      {0xfa, 2},  {0xfb, 5},  {0xfd, 4},  {0xfe, 3},  {0xff, 9},
-  };
-  static constexpr unsigned char singletons0_lower[] = {
-      0xad, 0x78, 0x79, 0x8b, 0x8d, 0xa2, 0x30, 0x57, 0x58, 0x8b, 0x8c, 0x90,
-      0x1c, 0x1d, 0xdd, 0x0e, 0x0f, 0x4b, 0x4c, 0xfb, 0xfc, 0x2e, 0x2f, 0x3f,
-      0x5c, 0x5d, 0x5f, 0xb5, 0xe2, 0x84, 0x8d, 0x8e, 0x91, 0x92, 0xa9, 0xb1,
-      0xba, 0xbb, 0xc5, 0xc6, 0xc9, 0xca, 0xde, 0xe4, 0xe5, 0xff, 0x00, 0x04,
-      0x11, 0x12, 0x29, 0x31, 0x34, 0x37, 0x3a, 0x3b, 0x3d, 0x49, 0x4a, 0x5d,
-      0x84, 0x8e, 0x92, 0xa9, 0xb1, 0xb4, 0xba, 0xbb, 0xc6, 0xca, 0xce, 0xcf,
-      0xe4, 0xe5, 0x00, 0x04, 0x0d, 0x0e, 0x11, 0x12, 0x29, 0x31, 0x34, 0x3a,
-      0x3b, 0x45, 0x46, 0x49, 0x4a, 0x5e, 0x64, 0x65, 0x84, 0x91, 0x9b, 0x9d,
-      0xc9, 0xce, 0xcf, 0x0d, 0x11, 0x29, 0x45, 0x49, 0x57, 0x64, 0x65, 0x8d,
-      0x91, 0xa9, 0xb4, 0xba, 0xbb, 0xc5, 0xc9, 0xdf, 0xe4, 0xe5, 0xf0, 0x0d,
-      0x11, 0x45, 0x49, 0x64, 0x65, 0x80, 0x84, 0xb2, 0xbc, 0xbe, 0xbf, 0xd5,
-      0xd7, 0xf0, 0xf1, 0x83, 0x85, 0x8b, 0xa4, 0xa6, 0xbe, 0xbf, 0xc5, 0xc7,
-      0xce, 0xcf, 0xda, 0xdb, 0x48, 0x98, 0xbd, 0xcd, 0xc6, 0xce, 0xcf, 0x49,
-      0x4e, 0x4f, 0x57, 0x59, 0x5e, 0x5f, 0x89, 0x8e, 0x8f, 0xb1, 0xb6, 0xb7,
-      0xbf, 0xc1, 0xc6, 0xc7, 0xd7, 0x11, 0x16, 0x17, 0x5b, 0x5c, 0xf6, 0xf7,
-      0xfe, 0xff, 0x80, 0x0d, 0x6d, 0x71, 0xde, 0xdf, 0x0e, 0x0f, 0x1f, 0x6e,
-      0x6f, 0x1c, 0x1d, 0x5f, 0x7d, 0x7e, 0xae, 0xaf, 0xbb, 0xbc, 0xfa, 0x16,
-      0x17, 0x1e, 0x1f, 0x46, 0x47, 0x4e, 0x4f, 0x58, 0x5a, 0x5c, 0x5e, 0x7e,
-      0x7f, 0xb5, 0xc5, 0xd4, 0xd5, 0xdc, 0xf0, 0xf1, 0xf5, 0x72, 0x73, 0x8f,
-      0x74, 0x75, 0x96, 0x2f, 0x5f, 0x26, 0x2e, 0x2f, 0xa7, 0xaf, 0xb7, 0xbf,
-      0xc7, 0xcf, 0xd7, 0xdf, 0x9a, 0x40, 0x97, 0x98, 0x30, 0x8f, 0x1f, 0xc0,
-      0xc1, 0xce, 0xff, 0x4e, 0x4f, 0x5a, 0x5b, 0x07, 0x08, 0x0f, 0x10, 0x27,
-      0x2f, 0xee, 0xef, 0x6e, 0x6f, 0x37, 0x3d, 0x3f, 0x42, 0x45, 0x90, 0x91,
-      0xfe, 0xff, 0x53, 0x67, 0x75, 0xc8, 0xc9, 0xd0, 0xd1, 0xd8, 0xd9, 0xe7,
-      0xfe, 0xff,
-  };
-  static constexpr singleton singletons1[] = {
-      {0x00, 6},  {0x01, 1}, {0x03, 1},  {0x04, 2}, {0x08, 8},  {0x09, 2},
-      {0x0a, 5},  {0x0b, 2}, {0x0e, 4},  {0x10, 1}, {0x11, 2},  {0x12, 5},
-      {0x13, 17}, {0x14, 1}, {0x15, 2},  {0x17, 2}, {0x19, 13}, {0x1c, 5},
-      {0x1d, 8},  {0x24, 1}, {0x6a, 3},  {0x6b, 2}, {0xbc, 2},  {0xd1, 2},
-      {0xd4, 12}, {0xd5, 9}, {0xd6, 2},  {0xd7, 2}, {0xda, 1},  {0xe0, 5},
-      {0xe1, 2},  {0xe8, 2}, {0xee, 32}, {0xf0, 4}, {0xf8, 2},  {0xf9, 2},
-      {0xfa, 2},  {0xfb, 1},
-  };
-  static constexpr unsigned char singletons1_lower[] = {
-      0x0c, 0x27, 0x3b, 0x3e, 0x4e, 0x4f, 0x8f, 0x9e, 0x9e, 0x9f, 0x06, 0x07,
-      0x09, 0x36, 0x3d, 0x3e, 0x56, 0xf3, 0xd0, 0xd1, 0x04, 0x14, 0x18, 0x36,
-      0x37, 0x56, 0x57, 0x7f, 0xaa, 0xae, 0xaf, 0xbd, 0x35, 0xe0, 0x12, 0x87,
-      0x89, 0x8e, 0x9e, 0x04, 0x0d, 0x0e, 0x11, 0x12, 0x29, 0x31, 0x34, 0x3a,
-      0x45, 0x46, 0x49, 0x4a, 0x4e, 0x4f, 0x64, 0x65, 0x5c, 0xb6, 0xb7, 0x1b,
-      0x1c, 0x07, 0x08, 0x0a, 0x0b, 0x14, 0x17, 0x36, 0x39, 0x3a, 0xa8, 0xa9,
-      0xd8, 0xd9, 0x09, 0x37, 0x90, 0x91, 0xa8, 0x07, 0x0a, 0x3b, 0x3e, 0x66,
-      0x69, 0x8f, 0x92, 0x6f, 0x5f, 0xee, 0xef, 0x5a, 0x62, 0x9a, 0x9b, 0x27,
-      0x28, 0x55, 0x9d, 0xa0, 0xa1, 0xa3, 0xa4, 0xa7, 0xa8, 0xad, 0xba, 0xbc,
-      0xc4, 0x06, 0x0b, 0x0c, 0x15, 0x1d, 0x3a, 0x3f, 0x45, 0x51, 0xa6, 0xa7,
-      0xcc, 0xcd, 0xa0, 0x07, 0x19, 0x1a, 0x22, 0x25, 0x3e, 0x3f, 0xc5, 0xc6,
-      0x04, 0x20, 0x23, 0x25, 0x26, 0x28, 0x33, 0x38, 0x3a, 0x48, 0x4a, 0x4c,
-      0x50, 0x53, 0x55, 0x56, 0x58, 0x5a, 0x5c, 0x5e, 0x60, 0x63, 0x65, 0x66,
-      0x6b, 0x73, 0x78, 0x7d, 0x7f, 0x8a, 0xa4, 0xaa, 0xaf, 0xb0, 0xc0, 0xd0,
-      0xae, 0xaf, 0x79, 0xcc, 0x6e, 0x6f, 0x93,
-  };
-  static constexpr unsigned char normal0[] = {
-      0x00, 0x20, 0x5f, 0x22, 0x82, 0xdf, 0x04, 0x82, 0x44, 0x08, 0x1b, 0x04,
-      0x06, 0x11, 0x81, 0xac, 0x0e, 0x80, 0xab, 0x35, 0x28, 0x0b, 0x80, 0xe0,
-      0x03, 0x19, 0x08, 0x01, 0x04, 0x2f, 0x04, 0x34, 0x04, 0x07, 0x03, 0x01,
-      0x07, 0x06, 0x07, 0x11, 0x0a, 0x50, 0x0f, 0x12, 0x07, 0x55, 0x07, 0x03,
-      0x04, 0x1c, 0x0a, 0x09, 0x03, 0x08, 0x03, 0x07, 0x03, 0x02, 0x03, 0x03,
-      0x03, 0x0c, 0x04, 0x05, 0x03, 0x0b, 0x06, 0x01, 0x0e, 0x15, 0x05, 0x3a,
-      0x03, 0x11, 0x07, 0x06, 0x05, 0x10, 0x07, 0x57, 0x07, 0x02, 0x07, 0x15,
-      0x0d, 0x50, 0x04, 0x43, 0x03, 0x2d, 0x03, 0x01, 0x04, 0x11, 0x06, 0x0f,
-      0x0c, 0x3a, 0x04, 0x1d, 0x25, 0x5f, 0x20, 0x6d, 0x04, 0x6a, 0x25, 0x80,
-      0xc8, 0x05, 0x82, 0xb0, 0x03, 0x1a, 0x06, 0x82, 0xfd, 0x03, 0x59, 0x07,
-      0x15, 0x0b, 0x17, 0x09, 0x14, 0x0c, 0x14, 0x0c, 0x6a, 0x06, 0x0a, 0x06,
-      0x1a, 0x06, 0x59, 0x07, 0x2b, 0x05, 0x46, 0x0a, 0x2c, 0x04, 0x0c, 0x04,
-      0x01, 0x03, 0x31, 0x0b, 0x2c, 0x04, 0x1a, 0x06, 0x0b, 0x03, 0x80, 0xac,
-      0x06, 0x0a, 0x06, 0x21, 0x3f, 0x4c, 0x04, 0x2d, 0x03, 0x74, 0x08, 0x3c,
-      0x03, 0x0f, 0x03, 0x3c, 0x07, 0x38, 0x08, 0x2b, 0x05, 0x82, 0xff, 0x11,
-      0x18, 0x08, 0x2f, 0x11, 0x2d, 0x03, 0x20, 0x10, 0x21, 0x0f, 0x80, 0x8c,
-      0x04, 0x82, 0x97, 0x19, 0x0b, 0x15, 0x88, 0x94, 0x05, 0x2f, 0x05, 0x3b,
-      0x07, 0x02, 0x0e, 0x18, 0x09, 0x80, 0xb3, 0x2d, 0x74, 0x0c, 0x80, 0xd6,
-      0x1a, 0x0c, 0x05, 0x80, 0xff, 0x05, 0x80, 0xdf, 0x0c, 0xee, 0x0d, 0x03,
-      0x84, 0x8d, 0x03, 0x37, 0x09, 0x81, 0x5c, 0x14, 0x80, 0xb8, 0x08, 0x80,
-      0xcb, 0x2a, 0x38, 0x03, 0x0a, 0x06, 0x38, 0x08, 0x46, 0x08, 0x0c, 0x06,
-      0x74, 0x0b, 0x1e, 0x03, 0x5a, 0x04, 0x59, 0x09, 0x80, 0x83, 0x18, 0x1c,
-      0x0a, 0x16, 0x09, 0x4c, 0x04, 0x80, 0x8a, 0x06, 0xab, 0xa4, 0x0c, 0x17,
-      0x04, 0x31, 0xa1, 0x04, 0x81, 0xda, 0x26, 0x07, 0x0c, 0x05, 0x05, 0x80,
-      0xa5, 0x11, 0x81, 0x6d, 0x10, 0x78, 0x28, 0x2a, 0x06, 0x4c, 0x04, 0x80,
-      0x8d, 0x04, 0x80, 0xbe, 0x03, 0x1b, 0x03, 0x0f, 0x0d,
-  };
-  static constexpr unsigned char normal1[] = {
-      0x5e, 0x22, 0x7b, 0x05, 0x03, 0x04, 0x2d, 0x03, 0x66, 0x03, 0x01, 0x2f,
-      0x2e, 0x80, 0x82, 0x1d, 0x03, 0x31, 0x0f, 0x1c, 0x04, 0x24, 0x09, 0x1e,
-      0x05, 0x2b, 0x05, 0x44, 0x04, 0x0e, 0x2a, 0x80, 0xaa, 0x06, 0x24, 0x04,
-      0x24, 0x04, 0x28, 0x08, 0x34, 0x0b, 0x01, 0x80, 0x90, 0x81, 0x37, 0x09,
-      0x16, 0x0a, 0x08, 0x80, 0x98, 0x39, 0x03, 0x63, 0x08, 0x09, 0x30, 0x16,
-      0x05, 0x21, 0x03, 0x1b, 0x05, 0x01, 0x40, 0x38, 0x04, 0x4b, 0x05, 0x2f,
-      0x04, 0x0a, 0x07, 0x09, 0x07, 0x40, 0x20, 0x27, 0x04, 0x0c, 0x09, 0x36,
-      0x03, 0x3a, 0x05, 0x1a, 0x07, 0x04, 0x0c, 0x07, 0x50, 0x49, 0x37, 0x33,
-      0x0d, 0x33, 0x07, 0x2e, 0x08, 0x0a, 0x81, 0x26, 0x52, 0x4e, 0x28, 0x08,
-      0x2a, 0x56, 0x1c, 0x14, 0x17, 0x09, 0x4e, 0x04, 0x1e, 0x0f, 0x43, 0x0e,
-      0x19, 0x07, 0x0a, 0x06, 0x48, 0x08, 0x27, 0x09, 0x75, 0x0b, 0x3f, 0x41,
-      0x2a, 0x06, 0x3b, 0x05, 0x0a, 0x06, 0x51, 0x06, 0x01, 0x05, 0x10, 0x03,
-      0x05, 0x80, 0x8b, 0x62, 0x1e, 0x48, 0x08, 0x0a, 0x80, 0xa6, 0x5e, 0x22,
-      0x45, 0x0b, 0x0a, 0x06, 0x0d, 0x13, 0x39, 0x07, 0x0a, 0x36, 0x2c, 0x04,
-      0x10, 0x80, 0xc0, 0x3c, 0x64, 0x53, 0x0c, 0x48, 0x09, 0x0a, 0x46, 0x45,
-      0x1b, 0x48, 0x08, 0x53, 0x1d, 0x39, 0x81, 0x07, 0x46, 0x0a, 0x1d, 0x03,
-      0x47, 0x49, 0x37, 0x03, 0x0e, 0x08, 0x0a, 0x06, 0x39, 0x07, 0x0a, 0x81,
-      0x36, 0x19, 0x80, 0xb7, 0x01, 0x0f, 0x32, 0x0d, 0x83, 0x9b, 0x66, 0x75,
-      0x0b, 0x80, 0xc4, 0x8a, 0xbc, 0x84, 0x2f, 0x8f, 0xd1, 0x82, 0x47, 0xa1,
-      0xb9, 0x82, 0x39, 0x07, 0x2a, 0x04, 0x02, 0x60, 0x26, 0x0a, 0x46, 0x0a,
-      0x28, 0x05, 0x13, 0x82, 0xb0, 0x5b, 0x65, 0x4b, 0x04, 0x39, 0x07, 0x11,
-      0x40, 0x05, 0x0b, 0x02, 0x0e, 0x97, 0xf8, 0x08, 0x84, 0xd6, 0x2a, 0x09,
-      0xa2, 0xf7, 0x81, 0x1f, 0x31, 0x03, 0x11, 0x04, 0x08, 0x81, 0x8c, 0x89,
-      0x04, 0x6b, 0x05, 0x0d, 0x03, 0x09, 0x07, 0x10, 0x93, 0x60, 0x80, 0xf6,
-      0x0a, 0x73, 0x08, 0x6e, 0x17, 0x46, 0x80, 0x9a, 0x14, 0x0c, 0x57, 0x09,
-      0x19, 0x80, 0x87, 0x81, 0x47, 0x03, 0x85, 0x42, 0x0f, 0x15, 0x85, 0x50,
-      0x2b, 0x80, 0xd5, 0x2d, 0x03, 0x1a, 0x04, 0x02, 0x81, 0x70, 0x3a, 0x05,
-      0x01, 0x85, 0x00, 0x80, 0xd7, 0x29, 0x4c, 0x04, 0x0a, 0x04, 0x02, 0x83,
-      0x11, 0x44, 0x4c, 0x3d, 0x80, 0xc2, 0x3c, 0x06, 0x01, 0x04, 0x55, 0x05,
-      0x1b, 0x34, 0x02, 0x81, 0x0e, 0x2c, 0x04, 0x64, 0x0c, 0x56, 0x0a, 0x80,
-      0xae, 0x38, 0x1d, 0x0d, 0x2c, 0x04, 0x09, 0x07, 0x02, 0x0e, 0x06, 0x80,
-      0x9a, 0x83, 0xd8, 0x08, 0x0d, 0x03, 0x0d, 0x03, 0x74, 0x0c, 0x59, 0x07,
-      0x0c, 0x14, 0x0c, 0x04, 0x38, 0x08, 0x0a, 0x06, 0x28, 0x08, 0x22, 0x4e,
-      0x81, 0x54, 0x0c, 0x15, 0x03, 0x03, 0x05, 0x07, 0x09, 0x19, 0x07, 0x07,
-      0x09, 0x03, 0x0d, 0x07, 0x29, 0x80, 0xcb, 0x25, 0x0a, 0x84, 0x06,
-  };
-  auto lower = static_cast<uint16_t>(cp);
-  if (cp < 0x10000) {
-    return is_printable(lower, singletons0,
-                        sizeof(singletons0) / sizeof(*singletons0),
-                        singletons0_lower, normal0, sizeof(normal0));
-  }
-  if (cp < 0x20000) {
-    return is_printable(lower, singletons1,
-                        sizeof(singletons1) / sizeof(*singletons1),
-                        singletons1_lower, normal1, sizeof(normal1));
-  }
-  if (0x2a6de <= cp && cp < 0x2a700) return false;
-  if (0x2b735 <= cp && cp < 0x2b740) return false;
-  if (0x2b81e <= cp && cp < 0x2b820) return false;
-  if (0x2cea2 <= cp && cp < 0x2ceb0) return false;
-  if (0x2ebe1 <= cp && cp < 0x2f800) return false;
-  if (0x2fa1e <= cp && cp < 0x30000) return false;
-  if (0x3134b <= cp && cp < 0xe0100) return false;
-  if (0xe01f0 <= cp && cp < 0x110000) return false;
-  return cp < 0x110000;
+template <typename Tuple1, typename Tuple2, typename F, size_t... Is>
+void for_each2(index_sequence<Is...>, Tuple1&& t1, Tuple2&& t2, F&& f) {
+  using std::get;
+  const int unused[] = {0, ((void)f(get<Is>(t1), get<Is>(t2)), 0)...};
+  ignore_unused(unused);
 }
 
-inline auto needs_escape(uint32_t cp) -> bool {
-  return cp < 0x20 || cp == 0x7f || cp == '"' || cp == '\\' ||
-         !is_printable(cp);
+template <typename Tuple1, typename Tuple2, typename F>
+void for_each2(Tuple1&& t1, Tuple2&& t2, F&& f) {
+  for_each2(tuple_index_sequence<remove_cvref_t<Tuple1>>(),
+            std::forward<Tuple1>(t1), std::forward<Tuple2>(t2),
+            std::forward<F>(f));
 }
 
-template <typename Char> struct find_escape_result {
-  const Char* begin;
-  const Char* end;
-  uint32_t cp;
+namespace tuple {
+// Workaround a bug in MSVC 2019 (v140).
+template <typename Char, typename... T>
+using result_t = std::tuple<formatter<remove_cvref_t<T>, Char>...>;
+
+using std::get;
+template <typename Tuple, typename Char, std::size_t... Is>
+auto get_formatters(index_sequence<Is...>)
+    -> result_t<Char, decltype(get<Is>(std::declval<Tuple>()))...>;
+}  // namespace tuple
+
+#if FMT_MSC_VERSION && FMT_MSC_VERSION < 1920
+// Older MSVC doesn't get the reference type correctly for arrays.
+template <typename R> struct range_reference_type_impl {
+  using type = decltype(*detail::range_begin(std::declval<R&>()));
 };
 
-template <typename Char>
-auto find_escape(const Char* begin, const Char* end)
-    -> find_escape_result<Char> {
-  for (; begin != end; ++begin) {
-    auto cp = static_cast<typename std::make_unsigned<Char>::type>(*begin);
-    if (sizeof(Char) == 1 && cp >= 0x80) continue;
-    if (needs_escape(cp)) return {begin, begin + 1, cp};
-  }
-  return {begin, nullptr, 0};
-}
-
-inline auto find_escape(const char* begin, const char* end)
-    -> find_escape_result<char> {
-  if (!is_utf8()) return find_escape<char>(begin, end);
-  auto result = find_escape_result<char>{end, nullptr, 0};
-  for_each_codepoint(string_view(begin, to_unsigned(end - begin)),
-                     [&](uint32_t cp, string_view sv) {
-                       if (needs_escape(cp)) {
-                         result = {sv.begin(), sv.end(), cp};
-                         return false;
-                       }
-                       return true;
-                     });
-  return result;
-}
+template <typename T, std::size_t N> struct range_reference_type_impl<T[N]> {
+  using type = T&;
+};
 
-template <typename Char, typename OutputIt>
-auto write_range_entry(OutputIt out, basic_string_view<Char> str) -> OutputIt {
-  *out++ = '"';
-  auto begin = str.begin(), end = str.end();
-  do {
-    auto escape = find_escape(begin, end);
-    out = copy_str<Char>(begin, escape.begin, out);
-    begin = escape.end;
-    if (!begin) break;
-    auto c = static_cast<Char>(escape.cp);
-    switch (escape.cp) {
-    case '\n':
-      *out++ = '\\';
-      c = 'n';
-      break;
-    case '\r':
-      *out++ = '\\';
-      c = 'r';
-      break;
-    case '\t':
-      *out++ = '\\';
-      c = 't';
-      break;
-    case '"':
-      FMT_FALLTHROUGH;
-    case '\\':
-      *out++ = '\\';
-      break;
-    default:
-      if (is_utf8()) {
-        if (escape.cp < 0x100) {
-          out = format_to(out, "\\x{:02x}", escape.cp);
-          continue;
-        }
-        if (escape.cp < 0x10000) {
-          out = format_to(out, "\\u{:04x}", escape.cp);
-          continue;
-        }
-        if (escape.cp < 0x110000) {
-          out = format_to(out, "\\U{:08x}", escape.cp);
-          continue;
-        }
-      }
-      for (Char escape_char : basic_string_view<Char>(
-               escape.begin, to_unsigned(escape.end - escape.begin))) {
-        out = format_to(
-            out, "\\x{:02x}",
-            static_cast<typename std::make_unsigned<Char>::type>(escape_char));
-      }
-      continue;
-    }
-    *out++ = c;
-  } while (begin != end);
-  *out++ = '"';
-  return out;
-}
+template <typename T>
+using range_reference_type = typename range_reference_type_impl<T>::type;
+#else
+template <typename Range>
+using range_reference_type =
+    decltype(*detail::range_begin(std::declval<Range&>()));
+#endif
 
-template <typename Char, typename OutputIt, typename T,
-          FMT_ENABLE_IF(std::is_convertible<T, std_string_view<char>>::value)>
-inline auto write_range_entry(OutputIt out, const T& str) -> OutputIt {
-  auto sv = std_string_view<Char>(str);
-  return write_range_entry<Char>(out, basic_string_view<Char>(sv));
-}
+// We don't use the Range's value_type for anything, but we do need the Range's
+// reference type, with cv-ref stripped.
+template <typename Range>
+using uncvref_type = remove_cvref_t<range_reference_type<Range>>;
 
-template <typename Char, typename OutputIt, typename Arg,
-          FMT_ENABLE_IF(std::is_same<Arg, Char>::value)>
-OutputIt write_range_entry(OutputIt out, const Arg v) {
-  *out++ = '\'';
-  *out++ = v;
-  *out++ = '\'';
-  return out;
+template <typename Formatter>
+FMT_CONSTEXPR auto maybe_set_debug_format(Formatter& f, bool set)
+    -> decltype(f.set_debug_format(set)) {
+  f.set_debug_format(set);
 }
+template <typename Formatter>
+FMT_CONSTEXPR void maybe_set_debug_format(Formatter&, ...) {}
+
+// These are not generic lambdas for compatibility with C++11.
+template <typename ParseContext> struct parse_empty_specs {
+  template <typename Formatter> FMT_CONSTEXPR void operator()(Formatter& f) {
+    f.parse(ctx);
+    detail::maybe_set_debug_format(f, true);
+  }
+  ParseContext& ctx;
+};
+template <typename FormatContext> struct format_tuple_element {
+  using char_type = typename FormatContext::char_type;
+
+  template <typename T>
+  void operator()(const formatter<T, char_type>& f, const T& v) {
+    if (i > 0)
+      ctx.advance_to(detail::copy_str<char_type>(separator, ctx.out()));
+    ctx.advance_to(f.format(v, ctx));
+    ++i;
+  }
 
-template <
-    typename Char, typename OutputIt, typename Arg,
-    FMT_ENABLE_IF(!is_std_string_like<typename std::decay<Arg>::type>::value &&
-                  !std::is_same<Arg, Char>::value)>
-OutputIt write_range_entry(OutputIt out, const Arg& v) {
-  return write<Char>(out, v);
-}
+  int i;
+  FormatContext& ctx;
+  basic_string_view<char_type> separator;
+};
 
 }  // namespace detail
 
 template <typename T> struct is_tuple_like {
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       detail::is_tuple_like_<T>::value && !detail::is_range_<T>::value;
 };
 
-template <typename TupleT, typename Char>
-struct formatter<TupleT, Char, enable_if_t<fmt::is_tuple_like<TupleT>::value>> {
+template <typename T, typename C> struct is_tuple_formattable {
+  static constexpr const bool value =
+      detail::is_tuple_formattable_<T, C>::value;
+};
+
+template <typename Tuple, typename Char>
+struct formatter<Tuple, Char,
+                 enable_if_t<fmt::is_tuple_like<Tuple>::value &&
+                             fmt::is_tuple_formattable<Tuple, Char>::value>> {
  private:
-  // C++11 generic lambda for format().
-  template <typename FormatContext> struct format_each {
-    template <typename T> void operator()(const T& v) {
-      if (i > 0) out = detail::write_delimiter(out);
-      out = detail::write_range_entry<Char>(out, v);
-      ++i;
-    }
-    int i;
-    typename FormatContext::iterator& out;
-  };
+  decltype(detail::tuple::get_formatters<Tuple, Char>(
+      detail::tuple_index_sequence<Tuple>())) formatters_;
+
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '('>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ')'>{};
 
  public:
+  FMT_CONSTEXPR formatter() {}
+
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
+  }
+
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
+  }
+
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
+    auto it = ctx.begin();
+    if (it != ctx.end() && *it != '}')
+      FMT_THROW(format_error("invalid format specifier"));
+    detail::for_each(formatters_, detail::parse_empty_specs<ParseContext>{ctx});
+    return it;
   }
 
-  template <typename FormatContext = format_context>
-  auto format(const TupleT& values, FormatContext& ctx) -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    *out++ = '(';
-    detail::for_each(values, format_each<FormatContext>{0, out});
-    *out++ = ')';
-    return out;
+  template <typename FormatContext>
+  auto format(const Tuple& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    ctx.advance_to(detail::copy_str<Char>(opening_bracket_, ctx.out()));
+    detail::for_each2(
+        formatters_, value,
+        detail::format_tuple_element<FormatContext>{0, ctx, separator_});
+    return detail::copy_str<Char>(closing_bracket_, ctx.out());
   }
 };
 
 template <typename T, typename Char> struct is_range {
-  static FMT_CONSTEXPR_DECL const bool value =
+  static constexpr const bool value =
       detail::is_range_<T>::value && !detail::is_std_string_like<T>::value &&
-      !detail::is_map<T>::value &&
       !std::is_convertible<T, std::basic_string<Char>>::value &&
-      !std::is_constructible<detail::std_string_view<Char>, T>::value;
+      !std::is_convertible<T, detail::std_string_view<Char>>::value;
+};
+
+namespace detail {
+template <typename Context> struct range_mapper {
+  using mapper = arg_mapper<Context>;
+
+  template <typename T,
+            FMT_ENABLE_IF(has_formatter<remove_cvref_t<T>, Context>::value)>
+  static auto map(T&& value) -> T&& {
+    return static_cast<T&&>(value);
+  }
+  template <typename T,
+            FMT_ENABLE_IF(!has_formatter<remove_cvref_t<T>, Context>::value)>
+  static auto map(T&& value)
+      -> decltype(mapper().map(static_cast<T&&>(value))) {
+    return mapper().map(static_cast<T&&>(value));
+  }
 };
 
+template <typename Char, typename Element>
+using range_formatter_type =
+    formatter<remove_cvref_t<decltype(range_mapper<buffer_context<Char>>{}.map(
+                  std::declval<Element>()))>,
+              Char>;
+
+template <typename R>
+using maybe_const_range =
+    conditional_t<has_const_begin_end<R>::value, const R, R>;
+
+// Workaround a bug in MSVC 2015 and earlier.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
+template <typename R, typename Char>
+struct is_formattable_delayed
+    : is_formattable<uncvref_type<maybe_const_range<R>>, Char> {};
+#endif
+}  // namespace detail
+
+template <typename T, typename Char, typename Enable = void>
+struct range_formatter;
+
 template <typename T, typename Char>
-struct formatter<
+struct range_formatter<
     T, Char,
-    enable_if_t<
-        fmt::is_range<T, Char>::value
-// Workaround a bug in MSVC 2019 and earlier.
-#if !FMT_MSC_VER
-        && (is_formattable<detail::value_type<T>, Char>::value ||
-            detail::has_fallback_formatter<detail::value_type<T>, Char>::value)
-#endif
-        >> {
+    enable_if_t<conjunction<std::is_same<T, remove_cvref_t<T>>,
+                            is_formattable<T, Char>>::value>> {
+ private:
+  detail::range_formatter_type<Char, T> underlying_;
+  basic_string_view<Char> separator_ = detail::string_literal<Char, ',', ' '>{};
+  basic_string_view<Char> opening_bracket_ =
+      detail::string_literal<Char, '['>{};
+  basic_string_view<Char> closing_bracket_ =
+      detail::string_literal<Char, ']'>{};
+
+ public:
+  FMT_CONSTEXPR range_formatter() {}
+
+  FMT_CONSTEXPR auto underlying() -> detail::range_formatter_type<Char, T>& {
+    return underlying_;
+  }
+
+  FMT_CONSTEXPR void set_separator(basic_string_view<Char> sep) {
+    separator_ = sep;
+  }
+
+  FMT_CONSTEXPR void set_brackets(basic_string_view<Char> open,
+                                  basic_string_view<Char> close) {
+    opening_bracket_ = open;
+    closing_bracket_ = close;
+  }
+
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
+    auto it = ctx.begin();
+    auto end = ctx.end();
+
+    if (it != end && *it == 'n') {
+      set_brackets({}, {});
+      ++it;
+    }
+
+    if (it != end && *it != '}') {
+      if (*it != ':') FMT_THROW(format_error("invalid format specifier"));
+      ++it;
+    } else {
+      detail::maybe_set_debug_format(underlying_, true);
+    }
+
+    ctx.advance_to(it);
+    return underlying_.parse(ctx);
   }
 
-  template <
-      typename FormatContext, typename U,
-      FMT_ENABLE_IF(
-          std::is_same<U, conditional_t<detail::has_const_begin_end<T>::value,
-                                        const T, T>>::value)>
-  auto format(U& range, FormatContext& ctx) -> decltype(ctx.out()) {
-#ifdef FMT_DEPRECATED_BRACED_RANGES
-    Char prefix = '{';
-    Char postfix = '}';
-#else
-    Char prefix = detail::is_set<T>::value ? '{' : '[';
-    Char postfix = detail::is_set<T>::value ? '}' : ']';
-#endif
+  template <typename R, typename FormatContext>
+  auto format(R&& range, FormatContext& ctx) const -> decltype(ctx.out()) {
+    detail::range_mapper<buffer_context<Char>> mapper;
     auto out = ctx.out();
-    *out++ = prefix;
+    out = detail::copy_str<Char>(opening_bracket_, out);
     int i = 0;
-    auto it = std::begin(range);
-    auto end = std::end(range);
+    auto it = detail::range_begin(range);
+    auto end = detail::range_end(range);
     for (; it != end; ++it) {
-      if (i > 0) out = detail::write_delimiter(out);
-      out = detail::write_range_entry<Char>(out, *it);
+      if (i > 0) out = detail::copy_str<Char>(separator_, out);
+      ctx.advance_to(out);
+      out = underlying_.format(mapper.map(*it), ctx);
       ++i;
     }
-    *out++ = postfix;
+    out = detail::copy_str<Char>(closing_bracket_, out);
     return out;
   }
 };
 
-template <typename T, typename Char>
-struct formatter<
-    T, Char,
-    enable_if_t<
-        detail::is_map<T>::value
-// Workaround a bug in MSVC 2019 and earlier.
-#if !FMT_MSC_VER
-        && (is_formattable<detail::value_type<T>, Char>::value ||
-            detail::has_fallback_formatter<detail::value_type<T>, Char>::value)
-#endif
-        >> {
+enum class range_format { disabled, map, set, sequence, string, debug_string };
+
+namespace detail {
+template <typename T>
+struct range_format_kind_
+    : std::integral_constant<range_format,
+                             std::is_same<uncvref_type<T>, T>::value
+                                 ? range_format::disabled
+                             : is_map<T>::value ? range_format::map
+                             : is_set<T>::value ? range_format::set
+                                                : range_format::sequence> {};
+
+template <range_format K, typename R, typename Char, typename Enable = void>
+struct range_default_formatter;
+
+template <range_format K>
+using range_format_constant = std::integral_constant<range_format, K>;
+
+template <range_format K, typename R, typename Char>
+struct range_default_formatter<
+    K, R, Char,
+    enable_if_t<(K == range_format::sequence || K == range_format::map ||
+                 K == range_format::set)>> {
+  using range_type = detail::maybe_const_range<R>;
+  range_formatter<detail::uncvref_type<range_type>, Char> underlying_;
+
+  FMT_CONSTEXPR range_default_formatter() { init(range_format_constant<K>()); }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::set>) {
+    underlying_.set_brackets(detail::string_literal<Char, '{'>{},
+                             detail::string_literal<Char, '}'>{});
+  }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::map>) {
+    underlying_.set_brackets(detail::string_literal<Char, '{'>{},
+                             detail::string_literal<Char, '}'>{});
+    underlying_.underlying().set_brackets({}, {});
+    underlying_.underlying().set_separator(
+        detail::string_literal<Char, ':', ' '>{});
+  }
+
+  FMT_CONSTEXPR void init(range_format_constant<range_format::sequence>) {}
+
   template <typename ParseContext>
   FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
-    return ctx.begin();
+    return underlying_.parse(ctx);
   }
 
-  template <
-      typename FormatContext, typename U,
-      FMT_ENABLE_IF(
-          std::is_same<U, conditional_t<detail::has_const_begin_end<T>::value,
-                                        const T, T>>::value)>
-  auto format(U& map, FormatContext& ctx) -> decltype(ctx.out()) {
-    auto out = ctx.out();
-    *out++ = '{';
-    int i = 0;
-    for (const auto& item : map) {
-      if (i > 0) out = detail::write_delimiter(out);
-      out = detail::write_range_entry<Char>(out, item.first);
-      *out++ = ':';
-      *out++ = ' ';
-      out = detail::write_range_entry<Char>(out, item.second);
-      ++i;
-    }
-    *out++ = '}';
-    return out;
+  template <typename FormatContext>
+  auto format(range_type& range, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    return underlying_.format(range, ctx);
   }
 };
+}  // namespace detail
+
+template <typename T, typename Char, typename Enable = void>
+struct range_format_kind
+    : conditional_t<
+          is_range<T, Char>::value, detail::range_format_kind_<T>,
+          std::integral_constant<range_format, range_format::disabled>> {};
+
+template <typename R, typename Char>
+struct formatter<
+    R, Char,
+    enable_if_t<conjunction<bool_constant<range_format_kind<R, Char>::value !=
+                                          range_format::disabled>
+// Workaround a bug in MSVC 2015 and earlier.
+#if !FMT_MSC_VERSION || FMT_MSC_VERSION >= 1910
+                            ,
+                            detail::is_formattable_delayed<R, Char>
+#endif
+                            >::value>>
+    : detail::range_default_formatter<range_format_kind<R, Char>::value, R,
+                                      Char> {
+};
 
 template <typename Char, typename... T> struct tuple_join_view : detail::view {
   const std::tuple<T...>& tuple;
@@ -672,9 +579,6 @@ template <typename Char, typename... T> struct tuple_join_view : detail::view {
       : tuple(t), sep{s} {}
 };
 
-template <typename Char, typename... T>
-using tuple_arg_join = tuple_join_view<Char, T...>;
-
 // Define FMT_TUPLE_JOIN_SPECIFIERS to enable experimental format specifiers
 // support in tuple_join. It is disabled by default because of issues with
 // the dynamic width and precision.
@@ -744,7 +648,42 @@ struct formatter<tuple_join_view<Char, T...>, Char> {
   }
 };
 
-FMT_MODULE_EXPORT_BEGIN
+namespace detail {
+// Check if T has an interface like a container adaptor (e.g. std::stack,
+// std::queue, std::priority_queue).
+template <typename T> class is_container_adaptor_like {
+  template <typename U> static auto check(U* p) -> typename U::container_type;
+  template <typename> static void check(...);
+
+ public:
+  static constexpr const bool value =
+      !std::is_void<decltype(check<T>(nullptr))>::value;
+};
+
+template <typename Container> struct all {
+  const Container& c;
+  auto begin() const -> typename Container::const_iterator { return c.begin(); }
+  auto end() const -> typename Container::const_iterator { return c.end(); }
+};
+}  // namespace detail
+
+template <typename T, typename Char>
+struct formatter<T, Char,
+                 enable_if_t<detail::is_container_adaptor_like<T>::value>>
+    : formatter<detail::all<typename T::container_type>, Char> {
+  using all = detail::all<typename T::container_type>;
+  template <typename FormatContext>
+  auto format(const T& t, FormatContext& ctx) const -> decltype(ctx.out()) {
+    struct getter : T {
+      static auto get(const T& t) -> all {
+        return {t.*(&getter::c)};  // Access c through the derived class.
+      }
+    };
+    return formatter<all>::format(getter::get(t), ctx);
+  }
+};
+
+FMT_BEGIN_EXPORT
 
 /**
   \rst
@@ -787,7 +726,7 @@ auto join(std::initializer_list<T> list, string_view sep)
   return join(std::begin(list), std::end(list), sep);
 }
 
-FMT_MODULE_EXPORT_END
+FMT_END_EXPORT
 FMT_END_NAMESPACE
 
 #endif  // FMT_RANGES_H_
diff --git a/contrib/fmt/include/fmt/std.h b/contrib/fmt/include/fmt/std.h
new file mode 100644
index 000000000..4c2a28cf8
--- /dev/null
+++ b/contrib/fmt/include/fmt/std.h
@@ -0,0 +1,349 @@
+// Formatting library for C++ - formatters for standard library types
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_STD_H_
+#define FMT_STD_H_
+
+#include <cstdlib>
+#include <exception>
+#include <memory>
+#include <thread>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+
+#include "ostream.h"
+
+#if FMT_HAS_INCLUDE(<version>)
+#  include <version>
+#endif
+// Checking FMT_CPLUSPLUS for warning suppression in MSVC.
+#if FMT_CPLUSPLUS >= 201703L
+#  if FMT_HAS_INCLUDE(<filesystem>)
+#    include <filesystem>
+#  endif
+#  if FMT_HAS_INCLUDE(<variant>)
+#    include <variant>
+#  endif
+#  if FMT_HAS_INCLUDE(<optional>)
+#    include <optional>
+#  endif
+#endif
+
+// GCC 4 does not support FMT_HAS_INCLUDE.
+#if FMT_HAS_INCLUDE(<cxxabi.h>) || defined(__GLIBCXX__)
+#  include <cxxabi.h>
+// Android NDK with gabi++ library on some architectures does not implement
+// abi::__cxa_demangle().
+#  ifndef __GABIXX_CXXABI_H__
+#    define FMT_HAS_ABI_CXA_DEMANGLE
+#  endif
+#endif
+
+#ifdef __cpp_lib_filesystem
+FMT_BEGIN_NAMESPACE
+
+namespace detail {
+
+template <typename Char>
+void write_escaped_path(basic_memory_buffer<Char>& quoted,
+                        const std::filesystem::path& p) {
+  write_escaped_string<Char>(std::back_inserter(quoted), p.string<Char>());
+}
+#  ifdef _WIN32
+template <>
+inline void write_escaped_path<char>(memory_buffer& quoted,
+                                     const std::filesystem::path& p) {
+  auto buf = basic_memory_buffer<wchar_t>();
+  write_escaped_string<wchar_t>(std::back_inserter(buf), p.native());
+  // Convert UTF-16 to UTF-8.
+  if (!unicode_to_utf8<wchar_t>::convert(quoted, {buf.data(), buf.size()}))
+    FMT_THROW(std::runtime_error("invalid utf16"));
+}
+#  endif
+template <>
+inline void write_escaped_path<std::filesystem::path::value_type>(
+    basic_memory_buffer<std::filesystem::path::value_type>& quoted,
+    const std::filesystem::path& p) {
+  write_escaped_string<std::filesystem::path::value_type>(
+      std::back_inserter(quoted), p.native());
+}
+
+}  // namespace detail
+
+FMT_MODULE_EXPORT
+template <typename Char>
+struct formatter<std::filesystem::path, Char>
+    : formatter<basic_string_view<Char>> {
+  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+    auto out = formatter<basic_string_view<Char>>::parse(ctx);
+    this->set_debug_format(false);
+    return out;
+  }
+  template <typename FormatContext>
+  auto format(const std::filesystem::path& p, FormatContext& ctx) const ->
+      typename FormatContext::iterator {
+    auto quoted = basic_memory_buffer<Char>();
+    detail::write_escaped_path(quoted, p);
+    return formatter<basic_string_view<Char>>::format(
+        basic_string_view<Char>(quoted.data(), quoted.size()), ctx);
+  }
+};
+FMT_END_NAMESPACE
+#endif
+
+FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
+template <typename Char>
+struct formatter<std::thread::id, Char> : basic_ostream_formatter<Char> {};
+FMT_END_NAMESPACE
+
+#ifdef __cpp_lib_optional
+FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
+template <typename T, typename Char>
+struct formatter<std::optional<T>, Char,
+                 std::enable_if_t<is_formattable<T, Char>::value>> {
+ private:
+  formatter<T, Char> underlying_;
+  static constexpr basic_string_view<Char> optional =
+      detail::string_literal<Char, 'o', 'p', 't', 'i', 'o', 'n', 'a', 'l',
+                             '('>{};
+  static constexpr basic_string_view<Char> none =
+      detail::string_literal<Char, 'n', 'o', 'n', 'e'>{};
+
+  template <class U>
+  FMT_CONSTEXPR static auto maybe_set_debug_format(U& u, bool set)
+      -> decltype(u.set_debug_format(set)) {
+    u.set_debug_format(set);
+  }
+
+  template <class U>
+  FMT_CONSTEXPR static void maybe_set_debug_format(U&, ...) {}
+
+ public:
+  template <typename ParseContext> FMT_CONSTEXPR auto parse(ParseContext& ctx) {
+    maybe_set_debug_format(underlying_, true);
+    return underlying_.parse(ctx);
+  }
+
+  template <typename FormatContext>
+  auto format(std::optional<T> const& opt, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    if (!opt) return detail::write<Char>(ctx.out(), none);
+
+    auto out = ctx.out();
+    out = detail::write<Char>(out, optional);
+    ctx.advance_to(out);
+    out = underlying_.format(*opt, ctx);
+    return detail::write(out, ')');
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_optional
+
+#ifdef __cpp_lib_variant
+FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
+template <typename Char> struct formatter<std::monostate, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const std::monostate&, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write<Char>(out, "monostate");
+    return out;
+  }
+};
+
+namespace detail {
+
+template <typename T>
+using variant_index_sequence =
+    std::make_index_sequence<std::variant_size<T>::value>;
+
+template <typename> struct is_variant_like_ : std::false_type {};
+template <typename... Types>
+struct is_variant_like_<std::variant<Types...>> : std::true_type {};
+
+// formattable element check.
+template <typename T, typename C> class is_variant_formattable_ {
+  template <std::size_t... Is>
+  static std::conjunction<
+      is_formattable<std::variant_alternative_t<Is, T>, C>...>
+      check(std::index_sequence<Is...>);
+
+ public:
+  static constexpr const bool value =
+      decltype(check(variant_index_sequence<T>{}))::value;
+};
+
+template <typename Char, typename OutputIt, typename T>
+auto write_variant_alternative(OutputIt out, const T& v) -> OutputIt {
+  if constexpr (is_string<T>::value)
+    return write_escaped_string<Char>(out, detail::to_string_view(v));
+  else if constexpr (std::is_same_v<T, Char>)
+    return write_escaped_char(out, v);
+  else
+    return write<Char>(out, v);
+}
+
+}  // namespace detail
+template <typename T> struct is_variant_like {
+  static constexpr const bool value = detail::is_variant_like_<T>::value;
+};
+
+template <typename T, typename C> struct is_variant_formattable {
+  static constexpr const bool value =
+      detail::is_variant_formattable_<T, C>::value;
+};
+
+FMT_MODULE_EXPORT
+template <typename Variant, typename Char>
+struct formatter<
+    Variant, Char,
+    std::enable_if_t<std::conjunction_v<
+        is_variant_like<Variant>, is_variant_formattable<Variant, Char>>>> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  auto format(const Variant& value, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+
+    out = detail::write<Char>(out, "variant(");
+    try {
+      std::visit(
+          [&](const auto& v) {
+            out = detail::write_variant_alternative<Char>(out, v);
+          },
+          value);
+    } catch (const std::bad_variant_access&) {
+      detail::write<Char>(out, "valueless by exception");
+    }
+    *out++ = ')';
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+#endif  // __cpp_lib_variant
+
+FMT_BEGIN_NAMESPACE
+FMT_MODULE_EXPORT
+template <typename Char> struct formatter<std::error_code, Char> {
+  template <typename ParseContext>
+  FMT_CONSTEXPR auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {
+    return ctx.begin();
+  }
+
+  template <typename FormatContext>
+  FMT_CONSTEXPR auto format(const std::error_code& ec, FormatContext& ctx) const
+      -> decltype(ctx.out()) {
+    auto out = ctx.out();
+    out = detail::write_bytes(out, ec.category().name(), format_specs<Char>());
+    out = detail::write<Char>(out, Char(':'));
+    out = detail::write<Char>(out, ec.value());
+    return out;
+  }
+};
+
+FMT_MODULE_EXPORT
+template <typename T, typename Char>
+struct formatter<
+    T, Char,
+    typename std::enable_if<std::is_base_of<std::exception, T>::value>::type> {
+ private:
+  bool with_typename_ = false;
+
+ public:
+  FMT_CONSTEXPR auto parse(basic_format_parse_context<Char>& ctx)
+      -> decltype(ctx.begin()) {
+    auto it = ctx.begin();
+    auto end = ctx.end();
+    if (it == end || *it == '}') return it;
+    if (*it == 't') {
+      ++it;
+      with_typename_ = true;
+    }
+    return it;
+  }
+
+  template <typename OutputIt>
+  auto format(const std::exception& ex,
+              basic_format_context<OutputIt, Char>& ctx) const -> OutputIt {
+    format_specs<Char> spec;
+    auto out = ctx.out();
+    if (!with_typename_)
+      return detail::write_bytes(out, string_view(ex.what()), spec);
+
+    const std::type_info& ti = typeid(ex);
+#ifdef FMT_HAS_ABI_CXA_DEMANGLE
+    int status = 0;
+    std::size_t size = 0;
+    std::unique_ptr<char, decltype(&std::free)> demangled_name_ptr(
+        abi::__cxa_demangle(ti.name(), nullptr, &size, &status), &std::free);
+
+    string_view demangled_name_view;
+    if (demangled_name_ptr) {
+      demangled_name_view = demangled_name_ptr.get();
+
+      // Normalization of stdlib inline namespace names.
+      // libc++ inline namespaces.
+      //  std::__1::*       -> std::*
+      //  std::__1::__fs::* -> std::*
+      // libstdc++ inline namespaces.
+      //  std::__cxx11::*             -> std::*
+      //  std::filesystem::__cxx11::* -> std::filesystem::*
+      if (demangled_name_view.starts_with("std::")) {
+        char* begin = demangled_name_ptr.get();
+        char* to = begin + 5;  // std::
+        for (char *from = to, *end = begin + demangled_name_view.size();
+             from < end;) {
+          // This is safe, because demangled_name is NUL-terminated.
+          if (from[0] == '_' && from[1] == '_') {
+            char* next = from + 1;
+            while (next < end && *next != ':') next++;
+            if (next[0] == ':' && next[1] == ':') {
+              from = next + 2;
+              continue;
+            }
+          }
+          *to++ = *from++;
+        }
+        demangled_name_view = {begin, detail::to_unsigned(to - begin)};
+      }
+    } else {
+      demangled_name_view = string_view(ti.name());
+    }
+    out = detail::write_bytes(out, demangled_name_view, spec);
+#elif FMT_MSC_VERSION
+    string_view demangled_name_view(ti.name());
+    if (demangled_name_view.starts_with("class "))
+      demangled_name_view.remove_prefix(6);
+    else if (demangled_name_view.starts_with("struct "))
+      demangled_name_view.remove_prefix(7);
+    out = detail::write_bytes(out, demangled_name_view, spec);
+#else
+    out = detail::write_bytes(out, string_view(ti.name()), spec);
+#endif
+    out = detail::write<Char>(out, Char(':'));
+    out = detail::write<Char>(out, Char(' '));
+    out = detail::write_bytes(out, string_view(ex.what()), spec);
+
+    return out;
+  }
+};
+FMT_END_NAMESPACE
+
+#endif  // FMT_STD_H_
diff --git a/contrib/fmt/include/fmt/xchar.h b/contrib/fmt/include/fmt/xchar.h
new file mode 100644
index 000000000..4b87f8d12
--- /dev/null
+++ b/contrib/fmt/include/fmt/xchar.h
@@ -0,0 +1,259 @@
+// Formatting library for C++ - optional wchar_t and exotic character support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_XCHAR_H_
+#define FMT_XCHAR_H_
+
+#include <cwchar>
+
+#include "format.h"
+
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+#  include <locale>
+#endif
+
+FMT_BEGIN_NAMESPACE
+namespace detail {
+
+template <typename T>
+using is_exotic_char = bool_constant<!std::is_same<T, char>::value>;
+
+inline auto write_loc(std::back_insert_iterator<detail::buffer<wchar_t>> out,
+                      loc_value value, const format_specs<wchar_t>& specs,
+                      locale_ref loc) -> bool {
+#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
+  auto& numpunct =
+      std::use_facet<std::numpunct<wchar_t>>(loc.get<std::locale>());
+  auto separator = std::wstring();
+  auto grouping = numpunct.grouping();
+  if (!grouping.empty()) separator = std::wstring(1, numpunct.thousands_sep());
+  return value.visit(loc_writer<wchar_t>{out, specs, separator, grouping, {}});
+#endif
+  return false;
+}
+}  // namespace detail
+
+FMT_BEGIN_EXPORT
+
+using wstring_view = basic_string_view<wchar_t>;
+using wformat_parse_context = basic_format_parse_context<wchar_t>;
+using wformat_context = buffer_context<wchar_t>;
+using wformat_args = basic_format_args<wformat_context>;
+using wmemory_buffer = basic_memory_buffer<wchar_t>;
+
+#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
+// Workaround broken conversion on older gcc.
+template <typename... Args> using wformat_string = wstring_view;
+inline auto runtime(wstring_view s) -> wstring_view { return s; }
+#else
+template <typename... Args>
+using wformat_string = basic_format_string<wchar_t, type_identity_t<Args>...>;
+inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
+  return {{s}};
+}
+#endif
+
+template <> struct is_char<wchar_t> : std::true_type {};
+template <> struct is_char<detail::char8_type> : std::true_type {};
+template <> struct is_char<char16_t> : std::true_type {};
+template <> struct is_char<char32_t> : std::true_type {};
+
+template <typename... Args>
+constexpr format_arg_store<wformat_context, Args...> make_wformat_args(
+    const Args&... args) {
+  return {args...};
+}
+
+inline namespace literals {
+#if FMT_USE_USER_DEFINED_LITERALS && !FMT_USE_NONTYPE_TEMPLATE_ARGS
+constexpr detail::udl_arg<wchar_t> operator"" _a(const wchar_t* s, size_t) {
+  return {s};
+}
+#endif
+}  // namespace literals
+
+template <typename It, typename Sentinel>
+auto join(It begin, Sentinel end, wstring_view sep)
+    -> join_view<It, Sentinel, wchar_t> {
+  return {begin, end, sep};
+}
+
+template <typename Range>
+auto join(Range&& range, wstring_view sep)
+    -> join_view<detail::iterator_t<Range>, detail::sentinel_t<Range>,
+                 wchar_t> {
+  return join(std::begin(range), std::end(range), sep);
+}
+
+template <typename T>
+auto join(std::initializer_list<T> list, wstring_view sep)
+    -> join_view<const T*, const T*, wchar_t> {
+  return join(std::begin(list), std::end(list), sep);
+}
+
+template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
+auto vformat(basic_string_view<Char> format_str,
+             basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
+  basic_memory_buffer<Char> buffer;
+  detail::vformat_to(buffer, format_str, args);
+  return to_string(buffer);
+}
+
+template <typename... T>
+auto format(wformat_string<T...> fmt, T&&... args) -> std::wstring {
+  return vformat(fmt::wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+// Pass char_t as a default template parameter instead of using
+// std::basic_string<char_t<S>> to reduce the symbol size.
+template <typename S, typename... Args, typename Char = char_t<S>,
+          FMT_ENABLE_IF(!std::is_same<Char, char>::value &&
+                        !std::is_same<Char, wchar_t>::value)>
+auto format(const S& format_str, Args&&... args) -> std::basic_string<Char> {
+  return vformat(detail::to_string_view(format_str),
+                 fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename Locale, typename S, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat(
+    const Locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> std::basic_string<Char> {
+  return detail::vformat(loc, detail::to_string_view(format_str), args);
+}
+
+template <typename Locale, typename S, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format(const Locale& loc, const S& format_str, Args&&... args)
+    -> std::basic_string<Char> {
+  return detail::vformat(loc, detail::to_string_view(format_str),
+                         fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename S, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+auto vformat_to(OutputIt out, const S& format_str,
+                basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  detail::vformat_to(buf, detail::to_string_view(format_str), args);
+  return detail::get_iterator(buf, out);
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format_to(OutputIt out, const S& fmt, Args&&... args) -> OutputIt {
+  return vformat_to(out, detail::to_string_view(fmt),
+                    fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename Locale, typename S, typename OutputIt, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_locale<Locale>::value&&
+                                detail::is_exotic_char<Char>::value)>
+inline auto vformat_to(
+    OutputIt out, const Locale& loc, const S& format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) -> OutputIt {
+  auto&& buf = detail::get_buffer<Char>(out);
+  vformat_to(buf, detail::to_string_view(format_str), args,
+             detail::locale_ref(loc));
+  return detail::get_iterator(buf, out);
+}
+
+template <
+    typename OutputIt, typename Locale, typename S, typename... Args,
+    typename Char = char_t<S>,
+    bool enable = detail::is_output_iterator<OutputIt, Char>::value&&
+        detail::is_locale<Locale>::value&& detail::is_exotic_char<Char>::value>
+inline auto format_to(OutputIt out, const Locale& loc, const S& format_str,
+                      Args&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  return vformat_to(out, loc, detail::to_string_view(format_str),
+                    fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename OutputIt, typename Char, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto vformat_to_n(
+    OutputIt out, size_t n, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args)
+    -> format_to_n_result<OutputIt> {
+  detail::iterator_buffer<OutputIt, Char, detail::fixed_buffer_traits> buf(out,
+                                                                           n);
+  detail::vformat_to(buf, format_str, args);
+  return {buf.out(), buf.count()};
+}
+
+template <typename OutputIt, typename S, typename... Args,
+          typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
+                            detail::is_exotic_char<Char>::value)>
+inline auto format_to_n(OutputIt out, size_t n, const S& fmt,
+                        const Args&... args) -> format_to_n_result<OutputIt> {
+  return vformat_to_n(out, n, detail::to_string_view(fmt),
+                      fmt::make_format_args<buffer_context<Char>>(args...));
+}
+
+template <typename S, typename... Args, typename Char = char_t<S>,
+          FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
+inline auto formatted_size(const S& fmt, Args&&... args) -> size_t {
+  detail::counting_buffer<Char> buf;
+  detail::vformat_to(buf, detail::to_string_view(fmt),
+                     fmt::make_format_args<buffer_context<Char>>(args...));
+  return buf.count();
+}
+
+inline void vprint(std::FILE* f, wstring_view fmt, wformat_args args) {
+  wmemory_buffer buffer;
+  detail::vformat_to(buffer, fmt, args);
+  buffer.push_back(L'\0');
+  if (std::fputws(buffer.data(), f) == -1)
+    FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
+}
+
+inline void vprint(wstring_view fmt, wformat_args args) {
+  vprint(stdout, fmt, args);
+}
+
+template <typename... T>
+void print(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return vprint(f, wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
+  return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
+}
+
+template <typename... T>
+void println(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
+  return print(f, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+template <typename... T> void println(wformat_string<T...> fmt, T&&... args) {
+  return print(L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
+}
+
+/**
+  Converts *value* to ``std::wstring`` using the default format for type *T*.
+ */
+template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
+  return format(FMT_STRING(L"{}"), value);
+}
+FMT_END_EXPORT
+FMT_END_NAMESPACE
+
+#endif  // FMT_XCHAR_H_
diff --git a/src/libserver/hyperscan_tools.cxx b/src/libserver/hyperscan_tools.cxx
index 2d762a475..ec051837e 100644
--- a/src/libserver/hyperscan_tools.cxx
+++ b/src/libserver/hyperscan_tools.cxx
@@ -1,11 +1,11 @@
-/*-
- * Copyright 2022 Vsevolod Stakhov
+/*
+ * Copyright 2023 Vsevolod Stakhov
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
- *   http://www.apache.org/licenses/LICENSE-2.0
+ *    http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 #include "config.h"
 
 #ifdef WITH_HYPERSCAN