Remove golang vendored directory (#18277)

* rm go vendor

* fix drone yaml

* add to gitignore

43 files changed, 0 insertions, 14608 deletions

diff --git a/vendor/golang.org/x/tools/go/analysis/analysis.go b/vendor/golang.org/x/tools/go/analysis/analysis.go
deleted file mode 100644
index d11505a165..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/analysis.go
+++ /dev/null
@@ -1,242 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package analysis
-
-import (
-	"flag"
-	"fmt"
-	"go/ast"
-	"go/token"
-	"go/types"
-	"reflect"
-
-	"golang.org/x/tools/internal/analysisinternal"
-)
-
-// An Analyzer describes an analysis function and its options.
-type Analyzer struct {
-	// The Name of the analyzer must be a valid Go identifier
-	// as it may appear in command-line flags, URLs, and so on.
-	Name string
-
-	// Doc is the documentation for the analyzer.
-	// The part before the first "\n\n" is the title
-	// (no capital or period, max ~60 letters).
-	Doc string
-
-	// Flags defines any flags accepted by the analyzer.
-	// The manner in which these flags are exposed to the user
-	// depends on the driver which runs the analyzer.
-	Flags flag.FlagSet
-
-	// Run applies the analyzer to a package.
-	// It returns an error if the analyzer failed.
-	//
-	// On success, the Run function may return a result
-	// computed by the Analyzer; its type must match ResultType.
-	// The driver makes this result available as an input to
-	// another Analyzer that depends directly on this one (see
-	// Requires) when it analyzes the same package.
-	//
-	// To pass analysis results between packages (and thus
-	// potentially between address spaces), use Facts, which are
-	// serializable.
-	Run func(*Pass) (interface{}, error)
-
-	// RunDespiteErrors allows the driver to invoke
-	// the Run method of this analyzer even on a
-	// package that contains parse or type errors.
-	RunDespiteErrors bool
-
-	// Requires is a set of analyzers that must run successfully
-	// before this one on a given package. This analyzer may inspect
-	// the outputs produced by each analyzer in Requires.
-	// The graph over analyzers implied by Requires edges must be acyclic.
-	//
-	// Requires establishes a "horizontal" dependency between
-	// analysis passes (different analyzers, same package).
-	Requires []*Analyzer
-
-	// ResultType is the type of the optional result of the Run function.
-	ResultType reflect.Type
-
-	// FactTypes indicates that this analyzer imports and exports
-	// Facts of the specified concrete types.
-	// An analyzer that uses facts may assume that its import
-	// dependencies have been similarly analyzed before it runs.
-	// Facts must be pointers.
-	//
-	// FactTypes establishes a "vertical" dependency between
-	// analysis passes (same analyzer, different packages).
-	FactTypes []Fact
-}
-
-func (a *Analyzer) String() string { return a.Name }
-
-func init() {
-	// Set the analysisinternal functions to be able to pass type errors
-	// to the Pass type without modifying the go/analysis API.
-	analysisinternal.SetTypeErrors = func(p interface{}, errors []types.Error) {
-		p.(*Pass).typeErrors = errors
-	}
-	analysisinternal.GetTypeErrors = func(p interface{}) []types.Error {
-		return p.(*Pass).typeErrors
-	}
-}
-
-// A Pass provides information to the Run function that
-// applies a specific analyzer to a single Go package.
-//
-// It forms the interface between the analysis logic and the driver
-// program, and has both input and an output components.
-//
-// As in a compiler, one pass may depend on the result computed by another.
-//
-// The Run function should not call any of the Pass functions concurrently.
-type Pass struct {
-	Analyzer *Analyzer // the identity of the current analyzer
-
-	// syntax and type information
-	Fset         *token.FileSet // file position information
-	Files        []*ast.File    // the abstract syntax tree of each file
-	OtherFiles   []string       // names of non-Go files of this package
-	IgnoredFiles []string       // names of ignored source files in this package
-	Pkg          *types.Package // type information about the package
-	TypesInfo    *types.Info    // type information about the syntax trees
-	TypesSizes   types.Sizes    // function for computing sizes of types
-
-	// Report reports a Diagnostic, a finding about a specific location
-	// in the analyzed source code such as a potential mistake.
-	// It may be called by the Run function.
-	Report func(Diagnostic)
-
-	// ResultOf provides the inputs to this analysis pass, which are
-	// the corresponding results of its prerequisite analyzers.
-	// The map keys are the elements of Analysis.Required,
-	// and the type of each corresponding value is the required
-	// analysis's ResultType.
-	ResultOf map[*Analyzer]interface{}
-
-	// -- facts --
-
-	// ImportObjectFact retrieves a fact associated with obj.
-	// Given a value ptr of type *T, where *T satisfies Fact,
-	// ImportObjectFact copies the value to *ptr.
-	//
-	// ImportObjectFact panics if called after the pass is complete.
-	// ImportObjectFact is not concurrency-safe.
-	ImportObjectFact func(obj types.Object, fact Fact) bool
-
-	// ImportPackageFact retrieves a fact associated with package pkg,
-	// which must be this package or one of its dependencies.
-	// See comments for ImportObjectFact.
-	ImportPackageFact func(pkg *types.Package, fact Fact) bool
-
-	// ExportObjectFact associates a fact of type *T with the obj,
-	// replacing any previous fact of that type.
-	//
-	// ExportObjectFact panics if it is called after the pass is
-	// complete, or if obj does not belong to the package being analyzed.
-	// ExportObjectFact is not concurrency-safe.
-	ExportObjectFact func(obj types.Object, fact Fact)
-
-	// ExportPackageFact associates a fact with the current package.
-	// See comments for ExportObjectFact.
-	ExportPackageFact func(fact Fact)
-
-	// AllPackageFacts returns a new slice containing all package facts of the analysis's FactTypes
-	// in unspecified order.
-	// WARNING: This is an experimental API and may change in the future.
-	AllPackageFacts func() []PackageFact
-
-	// AllObjectFacts returns a new slice containing all object facts of the analysis's FactTypes
-	// in unspecified order.
-	// WARNING: This is an experimental API and may change in the future.
-	AllObjectFacts func() []ObjectFact
-
-	// typeErrors contains types.Errors that are associated with the pkg.
-	typeErrors []types.Error
-
-	/* Further fields may be added in future. */
-	// For example, suggested or applied refactorings.
-}
-
-// PackageFact is a package together with an associated fact.
-// WARNING: This is an experimental API and may change in the future.
-type PackageFact struct {
-	Package *types.Package
-	Fact    Fact
-}
-
-// ObjectFact is an object together with an associated fact.
-// WARNING: This is an experimental API and may change in the future.
-type ObjectFact struct {
-	Object types.Object
-	Fact   Fact
-}
-
-// Reportf is a helper function that reports a Diagnostic using the
-// specified position and formatted error message.
-func (pass *Pass) Reportf(pos token.Pos, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	pass.Report(Diagnostic{Pos: pos, Message: msg})
-}
-
-// The Range interface provides a range. It's equivalent to and satisfied by
-// ast.Node.
-type Range interface {
-	Pos() token.Pos // position of first character belonging to the node
-	End() token.Pos // position of first character immediately after the node
-}
-
-// ReportRangef is a helper function that reports a Diagnostic using the
-// range provided. ast.Node values can be passed in as the range because
-// they satisfy the Range interface.
-func (pass *Pass) ReportRangef(rng Range, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	pass.Report(Diagnostic{Pos: rng.Pos(), End: rng.End(), Message: msg})
-}
-
-func (pass *Pass) String() string {
-	return fmt.Sprintf("%s@%s", pass.Analyzer.Name, pass.Pkg.Path())
-}
-
-// A Fact is an intermediate fact produced during analysis.
-//
-// Each fact is associated with a named declaration (a types.Object) or
-// with a package as a whole. A single object or package may have
-// multiple associated facts, but only one of any particular fact type.
-//
-// A Fact represents a predicate such as "never returns", but does not
-// represent the subject of the predicate such as "function F" or "package P".
-//
-// Facts may be produced in one analysis pass and consumed by another
-// analysis pass even if these are in different address spaces.
-// If package P imports Q, all facts about Q produced during
-// analysis of that package will be available during later analysis of P.
-// Facts are analogous to type export data in a build system:
-// just as export data enables separate compilation of several passes,
-// facts enable "separate analysis".
-//
-// Each pass (a, p) starts with the set of facts produced by the
-// same analyzer a applied to the packages directly imported by p.
-// The analysis may add facts to the set, and they may be exported in turn.
-// An analysis's Run function may retrieve facts by calling
-// Pass.Import{Object,Package}Fact and update them using
-// Pass.Export{Object,Package}Fact.
-//
-// A fact is logically private to its Analysis. To pass values
-// between different analyzers, use the results mechanism;
-// see Analyzer.Requires, Analyzer.ResultType, and Pass.ResultOf.
-//
-// A Fact type must be a pointer.
-// Facts are encoded and decoded using encoding/gob.
-// A Fact may implement the GobEncoder/GobDecoder interfaces
-// to customize its encoding. Fact encoding should not fail.
-//
-// A Fact should not be modified once exported.
-type Fact interface {
-	AFact() // dummy method to avoid type errors
-}
diff --git a/vendor/golang.org/x/tools/go/analysis/diagnostic.go b/vendor/golang.org/x/tools/go/analysis/diagnostic.go
deleted file mode 100644
index cd462a0cb5..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/diagnostic.go
+++ /dev/null
@@ -1,65 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package analysis
-
-import "go/token"
-
-// A Diagnostic is a message associated with a source location or range.
-//
-// An Analyzer may return a variety of diagnostics; the optional Category,
-// which should be a constant, may be used to classify them.
-// It is primarily intended to make it easy to look up documentation.
-//
-// If End is provided, the diagnostic is specified to apply to the range between
-// Pos and End.
-type Diagnostic struct {
-	Pos      token.Pos
-	End      token.Pos // optional
-	Category string    // optional
-	Message  string
-
-	// SuggestedFixes contains suggested fixes for a diagnostic which can be used to perform
-	// edits to a file that address the diagnostic.
-	// TODO(matloob): Should multiple SuggestedFixes be allowed for a diagnostic?
-	// Diagnostics should not contain SuggestedFixes that overlap.
-	// Experimental: This API is experimental and may change in the future.
-	SuggestedFixes []SuggestedFix // optional
-
-	// Experimental: This API is experimental and may change in the future.
-	Related []RelatedInformation // optional
-}
-
-// RelatedInformation contains information related to a diagnostic.
-// For example, a diagnostic that flags duplicated declarations of a
-// variable may include one RelatedInformation per existing
-// declaration.
-type RelatedInformation struct {
-	Pos     token.Pos
-	End     token.Pos
-	Message string
-}
-
-// A SuggestedFix is a code change associated with a Diagnostic that a user can choose
-// to apply to their code. Usually the SuggestedFix is meant to fix the issue flagged
-// by the diagnostic.
-// TextEdits for a SuggestedFix should not overlap. TextEdits for a SuggestedFix
-// should not contain edits for other packages.
-// Experimental: This API is experimental and may change in the future.
-type SuggestedFix struct {
-	// A description for this suggested fix to be shown to a user deciding
-	// whether to accept it.
-	Message   string
-	TextEdits []TextEdit
-}
-
-// A TextEdit represents the replacement of the code between Pos and End with the new text.
-// Each TextEdit should apply to a single file. End should not be earlier in the file than Pos.
-// Experimental: This API is experimental and may change in the future.
-type TextEdit struct {
-	// For a pure insertion, End can either be set to Pos or token.NoPos.
-	Pos     token.Pos
-	End     token.Pos
-	NewText []byte
-}
diff --git a/vendor/golang.org/x/tools/go/analysis/doc.go b/vendor/golang.org/x/tools/go/analysis/doc.go
deleted file mode 100644
index 94a3bd5d07..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/doc.go
+++ /dev/null
@@ -1,321 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-/*
-
-Package analysis defines the interface between a modular static
-analysis and an analysis driver program.
-
-
-Background
-
-A static analysis is a function that inspects a package of Go code and
-reports a set of diagnostics (typically mistakes in the code), and
-perhaps produces other results as well, such as suggested refactorings
-or other facts. An analysis that reports mistakes is informally called a
-"checker". For example, the printf checker reports mistakes in
-fmt.Printf format strings.
-
-A "modular" analysis is one that inspects one package at a time but can
-save information from a lower-level package and use it when inspecting a
-higher-level package, analogous to separate compilation in a toolchain.
-The printf checker is modular: when it discovers that a function such as
-log.Fatalf delegates to fmt.Printf, it records this fact, and checks
-calls to that function too, including calls made from another package.
-
-By implementing a common interface, checkers from a variety of sources
-can be easily selected, incorporated, and reused in a wide range of
-driver programs including command-line tools (such as vet), text editors and
-IDEs, build and test systems (such as go build, Bazel, or Buck), test
-frameworks, code review tools, code-base indexers (such as SourceGraph),
-documentation viewers (such as godoc), batch pipelines for large code
-bases, and so on.
-
-
-Analyzer
-
-The primary type in the API is Analyzer. An Analyzer statically
-describes an analysis function: its name, documentation, flags,
-relationship to other analyzers, and of course, its logic.
-
-To define an analysis, a user declares a (logically constant) variable
-of type Analyzer. Here is a typical example from one of the analyzers in
-the go/analysis/passes/ subdirectory:
-
-	package unusedresult
-
-	var Analyzer = &analysis.Analyzer{
-		Name: "unusedresult",
-		Doc:  "check for unused results of calls to some functions",
-		Run:  run,
-		...
-	}
-
-	func run(pass *analysis.Pass) (interface{}, error) {
-		...
-	}
-
-An analysis driver is a program such as vet that runs a set of
-analyses and prints the diagnostics that they report.
-The driver program must import the list of Analyzers it needs.
-Typically each Analyzer resides in a separate package.
-To add a new Analyzer to an existing driver, add another item to the list:
-
-	import ( "unusedresult"; "nilness"; "printf" )
-
-	var analyses = []*analysis.Analyzer{
-		unusedresult.Analyzer,
-		nilness.Analyzer,
-		printf.Analyzer,
-	}
-
-A driver may use the name, flags, and documentation to provide on-line
-help that describes the analyses it performs.
-The doc comment contains a brief one-line summary,
-optionally followed by paragraphs of explanation.
-
-The Analyzer type has more fields besides those shown above:
-
-	type Analyzer struct {
-		Name             string
-		Doc              string
-		Flags            flag.FlagSet
-		Run              func(*Pass) (interface{}, error)
-		RunDespiteErrors bool
-		ResultType       reflect.Type
-		Requires         []*Analyzer
-		FactTypes        []Fact
-	}
-
-The Flags field declares a set of named (global) flag variables that
-control analysis behavior. Unlike vet, analysis flags are not declared
-directly in the command line FlagSet; it is up to the driver to set the
-flag variables. A driver for a single analysis, a, might expose its flag
-f directly on the command line as -f, whereas a driver for multiple
-analyses might prefix the flag name by the analysis name (-a.f) to avoid
-ambiguity. An IDE might expose the flags through a graphical interface,
-and a batch pipeline might configure them from a config file.
-See the "findcall" analyzer for an example of flags in action.
-
-The RunDespiteErrors flag indicates whether the analysis is equipped to
-handle ill-typed code. If not, the driver will skip the analysis if
-there were parse or type errors.
-The optional ResultType field specifies the type of the result value
-computed by this analysis and made available to other analyses.
-The Requires field specifies a list of analyses upon which
-this one depends and whose results it may access, and it constrains the
-order in which a driver may run analyses.
-The FactTypes field is discussed in the section on Modularity.
-The analysis package provides a Validate function to perform basic
-sanity checks on an Analyzer, such as that its Requires graph is
-acyclic, its fact and result types are unique, and so on.
-
-Finally, the Run field contains a function to be called by the driver to
-execute the analysis on a single package. The driver passes it an
-instance of the Pass type.
-
-
-Pass
-
-A Pass describes a single unit of work: the application of a particular
-Analyzer to a particular package of Go code.
-The Pass provides information to the Analyzer's Run function about the
-package being analyzed, and provides operations to the Run function for
-reporting diagnostics and other information back to the driver.
-
-	type Pass struct {
-		Fset         *token.FileSet
-		Files        []*ast.File
-		OtherFiles   []string
-		IgnoredFiles []string
-		Pkg          *types.Package
-		TypesInfo    *types.Info
-		ResultOf     map[*Analyzer]interface{}
-		Report       func(Diagnostic)
-		...
-	}
-
-The Fset, Files, Pkg, and TypesInfo fields provide the syntax trees,
-type information, and source positions for a single package of Go code.
-
-The OtherFiles field provides the names, but not the contents, of non-Go
-files such as assembly that are part of this package. See the "asmdecl"
-or "buildtags" analyzers for examples of loading non-Go files and reporting
-diagnostics against them.
-
-The IgnoredFiles field provides the names, but not the contents,
-of ignored Go and non-Go source files that are not part of this package
-with the current build configuration but may be part of other build
-configurations. See the "buildtags" analyzer for an example of loading
-and checking IgnoredFiles.
-
-The ResultOf field provides the results computed by the analyzers
-required by this one, as expressed in its Analyzer.Requires field. The
-driver runs the required analyzers first and makes their results
-available in this map. Each Analyzer must return a value of the type
-described in its Analyzer.ResultType field.
-For example, the "ctrlflow" analyzer returns a *ctrlflow.CFGs, which
-provides a control-flow graph for each function in the package (see
-golang.org/x/tools/go/cfg); the "inspect" analyzer returns a value that
-enables other Analyzers to traverse the syntax trees of the package more
-efficiently; and the "buildssa" analyzer constructs an SSA-form
-intermediate representation.
-Each of these Analyzers extends the capabilities of later Analyzers
-without adding a dependency to the core API, so an analysis tool pays
-only for the extensions it needs.
-
-The Report function emits a diagnostic, a message associated with a
-source position. For most analyses, diagnostics are their primary
-result.
-For convenience, Pass provides a helper method, Reportf, to report a new
-diagnostic by formatting a string.
-Diagnostic is defined as:
-
-	type Diagnostic struct {
-		Pos      token.Pos
-		Category string // optional
-		Message  string
-	}
-
-The optional Category field is a short identifier that classifies the
-kind of message when an analysis produces several kinds of diagnostic.
-
-Many analyses want to associate diagnostics with a severity level.
-Because Diagnostic does not have a severity level field, an Analyzer's
-diagnostics effectively all have the same severity level. To separate which
-diagnostics are high severity and which are low severity, expose multiple
-Analyzers instead. Analyzers should also be separated when their
-diagnostics belong in different groups, or could be tagged differently
-before being shown to the end user. Analyzers should document their severity
-level to help downstream tools surface diagnostics properly.
-
-Most Analyzers inspect typed Go syntax trees, but a few, such as asmdecl
-and buildtag, inspect the raw text of Go source files or even non-Go
-files such as assembly. To report a diagnostic against a line of a
-raw text file, use the following sequence:
-
-	content, err := ioutil.ReadFile(filename)
-	if err != nil { ... }
-	tf := fset.AddFile(filename, -1, len(content))
-	tf.SetLinesForContent(content)
-	...
-	pass.Reportf(tf.LineStart(line), "oops")
-
-
-Modular analysis with Facts
-
-To improve efficiency and scalability, large programs are routinely
-built using separate compilation: units of the program are compiled
-separately, and recompiled only when one of their dependencies changes;
-independent modules may be compiled in parallel. The same technique may
-be applied to static analyses, for the same benefits. Such analyses are
-described as "modular".
-
-A compiler’s type checker is an example of a modular static analysis.
-Many other checkers we would like to apply to Go programs can be
-understood as alternative or non-standard type systems. For example,
-vet's printf checker infers whether a function has the "printf wrapper"
-type, and it applies stricter checks to calls of such functions. In
-addition, it records which functions are printf wrappers for use by
-later analysis passes to identify other printf wrappers by induction.
-A result such as “f is a printf wrapper” that is not interesting by
-itself but serves as a stepping stone to an interesting result (such as
-a diagnostic) is called a "fact".
-
-The analysis API allows an analysis to define new types of facts, to
-associate facts of these types with objects (named entities) declared
-within the current package, or with the package as a whole, and to query
-for an existing fact of a given type associated with an object or
-package.
-
-An Analyzer that uses facts must declare their types:
-
-	var Analyzer = &analysis.Analyzer{
-		Name:      "printf",
-		FactTypes: []analysis.Fact{new(isWrapper)},
-		...
-	}
-
-	type isWrapper struct{} // => *types.Func f “is a printf wrapper”
-
-The driver program ensures that facts for a pass’s dependencies are
-generated before analyzing the package and is responsible for propagating
-facts from one package to another, possibly across address spaces.
-Consequently, Facts must be serializable. The API requires that drivers
-use the gob encoding, an efficient, robust, self-describing binary
-protocol. A fact type may implement the GobEncoder/GobDecoder interfaces
-if the default encoding is unsuitable. Facts should be stateless.
-
-The Pass type has functions to import and export facts,
-associated either with an object or with a package:
-
-	type Pass struct {
-		...
-		ExportObjectFact func(types.Object, Fact)
-		ImportObjectFact func(types.Object, Fact) bool
-
-		ExportPackageFact func(fact Fact)
-		ImportPackageFact func(*types.Package, Fact) bool
-	}
-
-An Analyzer may only export facts associated with the current package or
-its objects, though it may import facts from any package or object that
-is an import dependency of the current package.
-
-Conceptually, ExportObjectFact(obj, fact) inserts fact into a hidden map keyed by
-the pair (obj, TypeOf(fact)), and the ImportObjectFact function
-retrieves the entry from this map and copies its value into the variable
-pointed to by fact. This scheme assumes that the concrete type of fact
-is a pointer; this assumption is checked by the Validate function.
-See the "printf" analyzer for an example of object facts in action.
-
-Some driver implementations (such as those based on Bazel and Blaze) do
-not currently apply analyzers to packages of the standard library.
-Therefore, for best results, analyzer authors should not rely on
-analysis facts being available for standard packages.
-For example, although the printf checker is capable of deducing during
-analysis of the log package that log.Printf is a printf wrapper,
-this fact is built in to the analyzer so that it correctly checks
-calls to log.Printf even when run in a driver that does not apply
-it to standard packages. We would like to remove this limitation in future.
-
-
-Testing an Analyzer
-
-The analysistest subpackage provides utilities for testing an Analyzer.
-In a few lines of code, it is possible to run an analyzer on a package
-of testdata files and check that it reported all the expected
-diagnostics and facts (and no more). Expectations are expressed using
-"// want ..." comments in the input code.
-
-
-Standalone commands
-
-Analyzers are provided in the form of packages that a driver program is
-expected to import. The vet command imports a set of several analyzers,
-but users may wish to define their own analysis commands that perform
-additional checks. To simplify the task of creating an analysis command,
-either for a single analyzer or for a whole suite, we provide the
-singlechecker and multichecker subpackages.
-
-The singlechecker package provides the main function for a command that
-runs one analyzer. By convention, each analyzer such as
-go/passes/findcall should be accompanied by a singlechecker-based
-command such as go/analysis/passes/findcall/cmd/findcall, defined in its
-entirety as:
-
-	package main
-
-	import (
-		"golang.org/x/tools/go/analysis/passes/findcall"
-		"golang.org/x/tools/go/analysis/singlechecker"
-	)
-
-	func main() { singlechecker.Main(findcall.Analyzer) }
-
-A tool that provides multiple analyzers can use multichecker in a
-similar way, giving it the list of Analyzers.
-
-*/
-package analysis
diff --git a/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go b/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go
deleted file mode 100644
index 4b7be2d1f5..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/flags.go
+++ /dev/null
@@ -1,388 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package analysisflags defines helpers for processing flags of
-// analysis driver tools.
-package analysisflags
-
-import (
-	"crypto/sha256"
-	"encoding/gob"
-	"encoding/json"
-	"flag"
-	"fmt"
-	"go/token"
-	"io"
-	"io/ioutil"
-	"log"
-	"os"
-	"strconv"
-	"strings"
-
-	"golang.org/x/tools/go/analysis"
-)
-
-// flags common to all {single,multi,unit}checkers.
-var (
-	JSON    = false // -json
-	Context = -1    // -c=N: if N>0, display offending line plus N lines of context
-)
-
-// Parse creates a flag for each of the analyzer's flags,
-// including (in multi mode) a flag named after the analyzer,
-// parses the flags, then filters and returns the list of
-// analyzers enabled by flags.
-//
-// The result is intended to be passed to unitchecker.Run or checker.Run.
-// Use in unitchecker.Run will gob.Register all fact types for the returned
-// graph of analyzers but of course not the ones only reachable from
-// dropped analyzers. To avoid inconsistency about which gob types are
-// registered from run to run, Parse itself gob.Registers all the facts
-// only reachable from dropped analyzers.
-// This is not a particularly elegant API, but this is an internal package.
-func Parse(analyzers []*analysis.Analyzer, multi bool) []*analysis.Analyzer {
-	// Connect each analysis flag to the command line as -analysis.flag.
-	enabled := make(map[*analysis.Analyzer]*triState)
-	for _, a := range analyzers {
-		var prefix string
-
-		// Add -NAME flag to enable it.
-		if multi {
-			prefix = a.Name + "."
-
-			enable := new(triState)
-			enableUsage := "enable " + a.Name + " analysis"
-			flag.Var(enable, a.Name, enableUsage)
-			enabled[a] = enable
-		}
-
-		a.Flags.VisitAll(func(f *flag.Flag) {
-			if !multi && flag.Lookup(f.Name) != nil {
-				log.Printf("%s flag -%s would conflict with driver; skipping", a.Name, f.Name)
-				return
-			}
-
-			name := prefix + f.Name
-			flag.Var(f.Value, name, f.Usage)
-		})
-	}
-
-	// standard flags: -flags, -V.
-	printflags := flag.Bool("flags", false, "print analyzer flags in JSON")
-	addVersionFlag()
-
-	// flags common to all checkers
-	flag.BoolVar(&JSON, "json", JSON, "emit JSON output")
-	flag.IntVar(&Context, "c", Context, `display offending line with this many lines of context`)
-
-	// Add shims for legacy vet flags to enable existing
-	// scripts that run vet to continue to work.
-	_ = flag.Bool("source", false, "no effect (deprecated)")
-	_ = flag.Bool("v", false, "no effect (deprecated)")
-	_ = flag.Bool("all", false, "no effect (deprecated)")
-	_ = flag.String("tags", "", "no effect (deprecated)")
-	for old, new := range vetLegacyFlags {
-		newFlag := flag.Lookup(new)
-		if newFlag != nil && flag.Lookup(old) == nil {
-			flag.Var(newFlag.Value, old, "deprecated alias for -"+new)
-		}
-	}
-
-	flag.Parse() // (ExitOnError)
-
-	// -flags: print flags so that go vet knows which ones are legitimate.
-	if *printflags {
-		printFlags()
-		os.Exit(0)
-	}
-
-	everything := expand(analyzers)
-
-	// If any -NAME flag is true,  run only those analyzers. Otherwise,
-	// if any -NAME flag is false, run all but those analyzers.
-	if multi {
-		var hasTrue, hasFalse bool
-		for _, ts := range enabled {
-			switch *ts {
-			case setTrue:
-				hasTrue = true
-			case setFalse:
-				hasFalse = true
-			}
-		}
-
-		var keep []*analysis.Analyzer
-		if hasTrue {
-			for _, a := range analyzers {
-				if *enabled[a] == setTrue {
-					keep = append(keep, a)
-				}
-			}
-			analyzers = keep
-		} else if hasFalse {
-			for _, a := range analyzers {
-				if *enabled[a] != setFalse {
-					keep = append(keep, a)
-				}
-			}
-			analyzers = keep
-		}
-	}
-
-	// Register fact types of skipped analyzers
-	// in case we encounter them in imported files.
-	kept := expand(analyzers)
-	for a := range everything {
-		if !kept[a] {
-			for _, f := range a.FactTypes {
-				gob.Register(f)
-			}
-		}
-	}
-
-	return analyzers
-}
-
-func expand(analyzers []*analysis.Analyzer) map[*analysis.Analyzer]bool {
-	seen := make(map[*analysis.Analyzer]bool)
-	var visitAll func([]*analysis.Analyzer)
-	visitAll = func(analyzers []*analysis.Analyzer) {
-		for _, a := range analyzers {
-			if !seen[a] {
-				seen[a] = true
-				visitAll(a.Requires)
-			}
-		}
-	}
-	visitAll(analyzers)
-	return seen
-}
-
-func printFlags() {
-	type jsonFlag struct {
-		Name  string
-		Bool  bool
-		Usage string
-	}
-	var flags []jsonFlag = nil
-	flag.VisitAll(func(f *flag.Flag) {
-		// Don't report {single,multi}checker debugging
-		// flags or fix as these have no effect on unitchecker
-		// (as invoked by 'go vet').
-		switch f.Name {
-		case "debug", "cpuprofile", "memprofile", "trace", "fix":
-			return
-		}
-
-		b, ok := f.Value.(interface{ IsBoolFlag() bool })
-		isBool := ok && b.IsBoolFlag()
-		flags = append(flags, jsonFlag{f.Name, isBool, f.Usage})
-	})
-	data, err := json.MarshalIndent(flags, "", "\t")
-	if err != nil {
-		log.Fatal(err)
-	}
-	os.Stdout.Write(data)
-}
-
-// addVersionFlag registers a -V flag that, if set,
-// prints the executable version and exits 0.
-//
-// If the -V flag already exists — for example, because it was already
-// registered by a call to cmd/internal/objabi.AddVersionFlag — then
-// addVersionFlag does nothing.
-func addVersionFlag() {
-	if flag.Lookup("V") == nil {
-		flag.Var(versionFlag{}, "V", "print version and exit")
-	}
-}
-
-// versionFlag minimally complies with the -V protocol required by "go vet".
-type versionFlag struct{}
-
-func (versionFlag) IsBoolFlag() bool { return true }
-func (versionFlag) Get() interface{} { return nil }
-func (versionFlag) String() string   { return "" }
-func (versionFlag) Set(s string) error {
-	if s != "full" {
-		log.Fatalf("unsupported flag value: -V=%s", s)
-	}
-
-	// This replicates the minimal subset of
-	// cmd/internal/objabi.AddVersionFlag, which is private to the
-	// go tool yet forms part of our command-line interface.
-	// TODO(adonovan): clarify the contract.
-
-	// Print the tool version so the build system can track changes.
-	// Formats:
-	//   $progname version devel ... buildID=...
-	//   $progname version go1.9.1
-	progname := os.Args[0]
-	f, err := os.Open(progname)
-	if err != nil {
-		log.Fatal(err)
-	}
-	h := sha256.New()
-	if _, err := io.Copy(h, f); err != nil {
-		log.Fatal(err)
-	}
-	f.Close()
-	fmt.Printf("%s version devel comments-go-here buildID=%02x\n",
-		progname, string(h.Sum(nil)))
-	os.Exit(0)
-	return nil
-}
-
-// A triState is a boolean that knows whether
-// it has been set to either true or false.
-// It is used to identify whether a flag appears;
-// the standard boolean flag cannot
-// distinguish missing from unset.
-// It also satisfies flag.Value.
-type triState int
-
-const (
-	unset triState = iota
-	setTrue
-	setFalse
-)
-
-func triStateFlag(name string, value triState, usage string) *triState {
-	flag.Var(&value, name, usage)
-	return &value
-}
-
-// triState implements flag.Value, flag.Getter, and flag.boolFlag.
-// They work like boolean flags: we can say vet -printf as well as vet -printf=true
-func (ts *triState) Get() interface{} {
-	return *ts == setTrue
-}
-
-func (ts triState) isTrue() bool {
-	return ts == setTrue
-}
-
-func (ts *triState) Set(value string) error {
-	b, err := strconv.ParseBool(value)
-	if err != nil {
-		// This error message looks poor but package "flag" adds
-		// "invalid boolean value %q for -NAME: %s"
-		return fmt.Errorf("want true or false")
-	}
-	if b {
-		*ts = setTrue
-	} else {
-		*ts = setFalse
-	}
-	return nil
-}
-
-func (ts *triState) String() string {
-	switch *ts {
-	case unset:
-		return "true"
-	case setTrue:
-		return "true"
-	case setFalse:
-		return "false"
-	}
-	panic("not reached")
-}
-
-func (ts triState) IsBoolFlag() bool {
-	return true
-}
-
-// Legacy flag support
-
-// vetLegacyFlags maps flags used by legacy vet to their corresponding
-// new names. The old names will continue to work.
-var vetLegacyFlags = map[string]string{
-	// Analyzer name changes
-	"bool":       "bools",
-	"buildtags":  "buildtag",
-	"methods":    "stdmethods",
-	"rangeloops": "loopclosure",
-
-	// Analyzer flags
-	"compositewhitelist":  "composites.whitelist",
-	"printfuncs":          "printf.funcs",
-	"shadowstrict":        "shadow.strict",
-	"unusedfuncs":         "unusedresult.funcs",
-	"unusedstringmethods": "unusedresult.stringmethods",
-}
-
-// ---- output helpers common to all drivers ----
-
-// PrintPlain prints a diagnostic in plain text form,
-// with context specified by the -c flag.
-func PrintPlain(fset *token.FileSet, diag analysis.Diagnostic) {
-	posn := fset.Position(diag.Pos)
-	fmt.Fprintf(os.Stderr, "%s: %s\n", posn, diag.Message)
-
-	// -c=N: show offending line plus N lines of context.
-	if Context >= 0 {
-		posn := fset.Position(diag.Pos)
-		end := fset.Position(diag.End)
-		if !end.IsValid() {
-			end = posn
-		}
-		data, _ := ioutil.ReadFile(posn.Filename)
-		lines := strings.Split(string(data), "\n")
-		for i := posn.Line - Context; i <= end.Line+Context; i++ {
-			if 1 <= i && i <= len(lines) {
-				fmt.Fprintf(os.Stderr, "%d\t%s\n", i, lines[i-1])
-			}
-		}
-	}
-}
-
-// A JSONTree is a mapping from package ID to analysis name to result.
-// Each result is either a jsonError or a list of jsonDiagnostic.
-type JSONTree map[string]map[string]interface{}
-
-// Add adds the result of analysis 'name' on package 'id'.
-// The result is either a list of diagnostics or an error.
-func (tree JSONTree) Add(fset *token.FileSet, id, name string, diags []analysis.Diagnostic, err error) {
-	var v interface{}
-	if err != nil {
-		type jsonError struct {
-			Err string `json:"error"`
-		}
-		v = jsonError{err.Error()}
-	} else if len(diags) > 0 {
-		type jsonDiagnostic struct {
-			Category string `json:"category,omitempty"`
-			Posn     string `json:"posn"`
-			Message  string `json:"message"`
-		}
-		var diagnostics []jsonDiagnostic
-		// TODO(matloob): Should the JSON diagnostics contain ranges?
-		// If so, how should they be formatted?
-		for _, f := range diags {
-			diagnostics = append(diagnostics, jsonDiagnostic{
-				Category: f.Category,
-				Posn:     fset.Position(f.Pos).String(),
-				Message:  f.Message,
-			})
-		}
-		v = diagnostics
-	}
-	if v != nil {
-		m, ok := tree[id]
-		if !ok {
-			m = make(map[string]interface{})
-			tree[id] = m
-		}
-		m[name] = v
-	}
-}
-
-func (tree JSONTree) Print() {
-	data, err := json.MarshalIndent(tree, "", "\t")
-	if err != nil {
-		log.Panicf("internal error: JSON marshaling failed: %v", err)
-	}
-	fmt.Printf("%s\n", data)
-}
diff --git a/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/help.go b/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
deleted file mode 100644
index ce92892c81..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
+++ /dev/null
@@ -1,96 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package analysisflags
-
-import (
-	"flag"
-	"fmt"
-	"log"
-	"os"
-	"sort"
-	"strings"
-
-	"golang.org/x/tools/go/analysis"
-)
-
-const help = `PROGNAME is a tool for static analysis of Go programs.
-
-PROGNAME examines Go source code and reports suspicious constructs,
-such as Printf calls whose arguments do not align with the format
-string. It uses heuristics that do not guarantee all reports are
-genuine problems, but it can find errors not caught by the compilers.
-`
-
-// Help implements the help subcommand for a multichecker or unitchecker
-// style command. The optional args specify the analyzers to describe.
-// Help calls log.Fatal if no such analyzer exists.
-func Help(progname string, analyzers []*analysis.Analyzer, args []string) {
-	// No args: show summary of all analyzers.
-	if len(args) == 0 {
-		fmt.Println(strings.Replace(help, "PROGNAME", progname, -1))
-		fmt.Println("Registered analyzers:")
-		fmt.Println()
-		sort.Slice(analyzers, func(i, j int) bool {
-			return analyzers[i].Name < analyzers[j].Name
-		})
-		for _, a := range analyzers {
-			title := strings.Split(a.Doc, "\n\n")[0]
-			fmt.Printf("    %-12s %s\n", a.Name, title)
-		}
-		fmt.Println("\nBy default all analyzers are run.")
-		fmt.Println("To select specific analyzers, use the -NAME flag for each one,")
-		fmt.Println(" or -NAME=false to run all analyzers not explicitly disabled.")
-
-		// Show only the core command-line flags.
-		fmt.Println("\nCore flags:")
-		fmt.Println()
-		fs := flag.NewFlagSet("", flag.ExitOnError)
-		flag.VisitAll(func(f *flag.Flag) {
-			if !strings.Contains(f.Name, ".") {
-				fs.Var(f.Value, f.Name, f.Usage)
-			}
-		})
-		fs.SetOutput(os.Stdout)
-		fs.PrintDefaults()
-
-		fmt.Printf("\nTo see details and flags of a specific analyzer, run '%s help name'.\n", progname)
-
-		return
-	}
-
-	// Show help on specific analyzer(s).
-outer:
-	for _, arg := range args {
-		for _, a := range analyzers {
-			if a.Name == arg {
-				paras := strings.Split(a.Doc, "\n\n")
-				title := paras[0]
-				fmt.Printf("%s: %s\n", a.Name, title)
-
-				// Show only the flags relating to this analysis,
-				// properly prefixed.
-				first := true
-				fs := flag.NewFlagSet(a.Name, flag.ExitOnError)
-				a.Flags.VisitAll(func(f *flag.Flag) {
-					if first {
-						first = false
-						fmt.Println("\nAnalyzer flags:")
-						fmt.Println()
-					}
-					fs.Var(f.Value, a.Name+"."+f.Name, f.Usage)
-				})
-				fs.SetOutput(os.Stdout)
-				fs.PrintDefaults()
-
-				if len(paras) > 1 {
-					fmt.Printf("\n%s\n", strings.Join(paras[1:], "\n\n"))
-				}
-
-				continue outer
-			}
-		}
-		log.Fatalf("Analyzer %q not registered", arg)
-	}
-}
diff --git a/vendor/golang.org/x/tools/go/analysis/internal/facts/facts.go b/vendor/golang.org/x/tools/go/analysis/internal/facts/facts.go
deleted file mode 100644
index 1fb69c6159..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/internal/facts/facts.go
+++ /dev/null
@@ -1,323 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package facts defines a serializable set of analysis.Fact.
-//
-// It provides a partial implementation of the Fact-related parts of the
-// analysis.Pass interface for use in analysis drivers such as "go vet"
-// and other build systems.
-//
-// The serial format is unspecified and may change, so the same version
-// of this package must be used for reading and writing serialized facts.
-//
-// The handling of facts in the analysis system parallels the handling
-// of type information in the compiler: during compilation of package P,
-// the compiler emits an export data file that describes the type of
-// every object (named thing) defined in package P, plus every object
-// indirectly reachable from one of those objects. Thus the downstream
-// compiler of package Q need only load one export data file per direct
-// import of Q, and it will learn everything about the API of package P
-// and everything it needs to know about the API of P's dependencies.
-//
-// Similarly, analysis of package P emits a fact set containing facts
-// about all objects exported from P, plus additional facts about only
-// those objects of P's dependencies that are reachable from the API of
-// package P; the downstream analysis of Q need only load one fact set
-// per direct import of Q.
-//
-// The notion of "exportedness" that matters here is that of the
-// compiler. According to the language spec, a method pkg.T.f is
-// unexported simply because its name starts with lowercase. But the
-// compiler must nonetheless export f so that downstream compilations can
-// accurately ascertain whether pkg.T implements an interface pkg.I
-// defined as interface{f()}. Exported thus means "described in export
-// data".
-//
-package facts
-
-import (
-	"bytes"
-	"encoding/gob"
-	"fmt"
-	"go/types"
-	"io/ioutil"
-	"log"
-	"reflect"
-	"sort"
-	"sync"
-
-	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/types/objectpath"
-)
-
-const debug = false
-
-// A Set is a set of analysis.Facts.
-//
-// Decode creates a Set of facts by reading from the imports of a given
-// package, and Encode writes out the set. Between these operation,
-// the Import and Export methods will query and update the set.
-//
-// All of Set's methods except String are safe to call concurrently.
-type Set struct {
-	pkg *types.Package
-	mu  sync.Mutex
-	m   map[key]analysis.Fact
-}
-
-type key struct {
-	pkg *types.Package
-	obj types.Object // (object facts only)
-	t   reflect.Type
-}
-
-// ImportObjectFact implements analysis.Pass.ImportObjectFact.
-func (s *Set) ImportObjectFact(obj types.Object, ptr analysis.Fact) bool {
-	if obj == nil {
-		panic("nil object")
-	}
-	key := key{pkg: obj.Pkg(), obj: obj, t: reflect.TypeOf(ptr)}
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	if v, ok := s.m[key]; ok {
-		reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
-		return true
-	}
-	return false
-}
-
-// ExportObjectFact implements analysis.Pass.ExportObjectFact.
-func (s *Set) ExportObjectFact(obj types.Object, fact analysis.Fact) {
-	if obj.Pkg() != s.pkg {
-		log.Panicf("in package %s: ExportObjectFact(%s, %T): can't set fact on object belonging another package",
-			s.pkg, obj, fact)
-	}
-	key := key{pkg: obj.Pkg(), obj: obj, t: reflect.TypeOf(fact)}
-	s.mu.Lock()
-	s.m[key] = fact // clobber any existing entry
-	s.mu.Unlock()
-}
-
-func (s *Set) AllObjectFacts(filter map[reflect.Type]bool) []analysis.ObjectFact {
-	var facts []analysis.ObjectFact
-	s.mu.Lock()
-	for k, v := range s.m {
-		if k.obj != nil && filter[k.t] {
-			facts = append(facts, analysis.ObjectFact{Object: k.obj, Fact: v})
-		}
-	}
-	s.mu.Unlock()
-	return facts
-}
-
-// ImportPackageFact implements analysis.Pass.ImportPackageFact.
-func (s *Set) ImportPackageFact(pkg *types.Package, ptr analysis.Fact) bool {
-	if pkg == nil {
-		panic("nil package")
-	}
-	key := key{pkg: pkg, t: reflect.TypeOf(ptr)}
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	if v, ok := s.m[key]; ok {
-		reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
-		return true
-	}
-	return false
-}
-
-// ExportPackageFact implements analysis.Pass.ExportPackageFact.
-func (s *Set) ExportPackageFact(fact analysis.Fact) {
-	key := key{pkg: s.pkg, t: reflect.TypeOf(fact)}
-	s.mu.Lock()
-	s.m[key] = fact // clobber any existing entry
-	s.mu.Unlock()
-}
-
-func (s *Set) AllPackageFacts(filter map[reflect.Type]bool) []analysis.PackageFact {
-	var facts []analysis.PackageFact
-	s.mu.Lock()
-	for k, v := range s.m {
-		if k.obj == nil && filter[k.t] {
-			facts = append(facts, analysis.PackageFact{Package: k.pkg, Fact: v})
-		}
-	}
-	s.mu.Unlock()
-	return facts
-}
-
-// gobFact is the Gob declaration of a serialized fact.
-type gobFact struct {
-	PkgPath string          // path of package
-	Object  objectpath.Path // optional path of object relative to package itself
-	Fact    analysis.Fact   // type and value of user-defined Fact
-}
-
-// Decode decodes all the facts relevant to the analysis of package pkg.
-// The read function reads serialized fact data from an external source
-// for one of of pkg's direct imports. The empty file is a valid
-// encoding of an empty fact set.
-//
-// It is the caller's responsibility to call gob.Register on all
-// necessary fact types.
-func Decode(pkg *types.Package, read func(packagePath string) ([]byte, error)) (*Set, error) {
-	// Compute the import map for this package.
-	// See the package doc comment.
-	packages := importMap(pkg.Imports())
-
-	// Read facts from imported packages.
-	// Facts may describe indirectly imported packages, or their objects.
-	m := make(map[key]analysis.Fact) // one big bucket
-	for _, imp := range pkg.Imports() {
-		logf := func(format string, args ...interface{}) {
-			if debug {
-				prefix := fmt.Sprintf("in %s, importing %s: ",
-					pkg.Path(), imp.Path())
-				log.Print(prefix, fmt.Sprintf(format, args...))
-			}
-		}
-
-		// Read the gob-encoded facts.
-		data, err := read(imp.Path())
-		if err != nil {
-			return nil, fmt.Errorf("in %s, can't import facts for package %q: %v",
-				pkg.Path(), imp.Path(), err)
-		}
-		if len(data) == 0 {
-			continue // no facts
-		}
-		var gobFacts []gobFact
-		if err := gob.NewDecoder(bytes.NewReader(data)).Decode(&gobFacts); err != nil {
-			return nil, fmt.Errorf("decoding facts for %q: %v", imp.Path(), err)
-		}
-		if debug {
-			logf("decoded %d facts: %v", len(gobFacts), gobFacts)
-		}
-
-		// Parse each one into a key and a Fact.
-		for _, f := range gobFacts {
-			factPkg := packages[f.PkgPath]
-			if factPkg == nil {
-				// Fact relates to a dependency that was
-				// unused in this translation unit. Skip.
-				logf("no package %q; discarding %v", f.PkgPath, f.Fact)
-				continue
-			}
-			key := key{pkg: factPkg, t: reflect.TypeOf(f.Fact)}
-			if f.Object != "" {
-				// object fact
-				obj, err := objectpath.Object(factPkg, f.Object)
-				if err != nil {
-					// (most likely due to unexported object)
-					// TODO(adonovan): audit for other possibilities.
-					logf("no object for path: %v; discarding %s", err, f.Fact)
-					continue
-				}
-				key.obj = obj
-				logf("read %T fact %s for %v", f.Fact, f.Fact, key.obj)
-			} else {
-				// package fact
-				logf("read %T fact %s for %v", f.Fact, f.Fact, factPkg)
-			}
-			m[key] = f.Fact
-		}
-	}
-
-	return &Set{pkg: pkg, m: m}, nil
-}
-
-// Encode encodes a set of facts to a memory buffer.
-//
-// It may fail if one of the Facts could not be gob-encoded, but this is
-// a sign of a bug in an Analyzer.
-func (s *Set) Encode() []byte {
-
-	// TODO(adonovan): opt: use a more efficient encoding
-	// that avoids repeating PkgPath for each fact.
-
-	// Gather all facts, including those from imported packages.
-	var gobFacts []gobFact
-
-	s.mu.Lock()
-	for k, fact := range s.m {
-		if debug {
-			log.Printf("%v => %s\n", k, fact)
-		}
-		var object objectpath.Path
-		if k.obj != nil {
-			path, err := objectpath.For(k.obj)
-			if err != nil {
-				if debug {
-					log.Printf("discarding fact %s about %s\n", fact, k.obj)
-				}
-				continue // object not accessible from package API; discard fact
-			}
-			object = path
-		}
-		gobFacts = append(gobFacts, gobFact{
-			PkgPath: k.pkg.Path(),
-			Object:  object,
-			Fact:    fact,
-		})
-	}
-	s.mu.Unlock()
-
-	// Sort facts by (package, object, type) for determinism.
-	sort.Slice(gobFacts, func(i, j int) bool {
-		x, y := gobFacts[i], gobFacts[j]
-		if x.PkgPath != y.PkgPath {
-			return x.PkgPath < y.PkgPath
-		}
-		if x.Object != y.Object {
-			return x.Object < y.Object
-		}
-		tx := reflect.TypeOf(x.Fact)
-		ty := reflect.TypeOf(y.Fact)
-		if tx != ty {
-			return tx.String() < ty.String()
-		}
-		return false // equal
-	})
-
-	var buf bytes.Buffer
-	if len(gobFacts) > 0 {
-		if err := gob.NewEncoder(&buf).Encode(gobFacts); err != nil {
-			// Fact encoding should never fail. Identify the culprit.
-			for _, gf := range gobFacts {
-				if err := gob.NewEncoder(ioutil.Discard).Encode(gf); err != nil {
-					fact := gf.Fact
-					pkgpath := reflect.TypeOf(fact).Elem().PkgPath()
-					log.Panicf("internal error: gob encoding of analysis fact %s failed: %v; please report a bug against fact %T in package %q",
-						fact, err, fact, pkgpath)
-				}
-			}
-		}
-	}
-
-	if debug {
-		log.Printf("package %q: encode %d facts, %d bytes\n",
-			s.pkg.Path(), len(gobFacts), buf.Len())
-	}
-
-	return buf.Bytes()
-}
-
-// String is provided only for debugging, and must not be called
-// concurrent with any Import/Export method.
-func (s *Set) String() string {
-	var buf bytes.Buffer
-	buf.WriteString("{")
-	for k, f := range s.m {
-		if buf.Len() > 1 {
-			buf.WriteString(", ")
-		}
-		if k.obj != nil {
-			buf.WriteString(k.obj.String())
-		} else {
-			buf.WriteString(k.pkg.Path())
-		}
-		fmt.Fprintf(&buf, ": %v", f)
-	}
-	buf.WriteString("}")
-	return buf.String()
-}
diff --git a/vendor/golang.org/x/tools/go/analysis/internal/facts/imports.go b/vendor/golang.org/x/tools/go/analysis/internal/facts/imports.go
deleted file mode 100644
index 34740f48e0..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/internal/facts/imports.go
+++ /dev/null
@@ -1,88 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package facts
-
-import "go/types"
-
-// importMap computes the import map for a package by traversing the
-// entire exported API each of its imports.
-//
-// This is a workaround for the fact that we cannot access the map used
-// internally by the types.Importer returned by go/importer. The entries
-// in this map are the packages and objects that may be relevant to the
-// current analysis unit.
-//
-// Packages in the map that are only indirectly imported may be
-// incomplete (!pkg.Complete()).
-//
-func importMap(imports []*types.Package) map[string]*types.Package {
-	objects := make(map[types.Object]bool)
-	packages := make(map[string]*types.Package)
-
-	var addObj func(obj types.Object) bool
-	var addType func(T types.Type)
-
-	addObj = func(obj types.Object) bool {
-		if !objects[obj] {
-			objects[obj] = true
-			addType(obj.Type())
-			if pkg := obj.Pkg(); pkg != nil {
-				packages[pkg.Path()] = pkg
-			}
-			return true
-		}
-		return false
-	}
-
-	addType = func(T types.Type) {
-		switch T := T.(type) {
-		case *types.Basic:
-			// nop
-		case *types.Named:
-			if addObj(T.Obj()) {
-				for i := 0; i < T.NumMethods(); i++ {
-					addObj(T.Method(i))
-				}
-			}
-		case *types.Pointer:
-			addType(T.Elem())
-		case *types.Slice:
-			addType(T.Elem())
-		case *types.Array:
-			addType(T.Elem())
-		case *types.Chan:
-			addType(T.Elem())
-		case *types.Map:
-			addType(T.Key())
-			addType(T.Elem())
-		case *types.Signature:
-			addType(T.Params())
-			addType(T.Results())
-		case *types.Struct:
-			for i := 0; i < T.NumFields(); i++ {
-				addObj(T.Field(i))
-			}
-		case *types.Tuple:
-			for i := 0; i < T.Len(); i++ {
-				addObj(T.At(i))
-			}
-		case *types.Interface:
-			for i := 0; i < T.NumMethods(); i++ {
-				addObj(T.Method(i))
-			}
-		}
-	}
-
-	for _, imp := range imports {
-		packages[imp.Path()] = imp
-
-		scope := imp.Scope()
-		for _, name := range scope.Names() {
-			addObj(scope.Lookup(name))
-		}
-	}
-
-	return packages
-}
diff --git a/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go b/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
deleted file mode 100644
index 713e1380ef..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
+++ /dev/null
@@ -1,398 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// The unitchecker package defines the main function for an analysis
-// driver that analyzes a single compilation unit during a build.
-// It is invoked by a build system such as "go vet":
-//
-//   $ go vet -vettool=$(which vet)
-//
-// It supports the following command-line protocol:
-//
-//      -V=full         describe executable               (to the build tool)
-//      -flags          describe flags                    (to the build tool)
-//      foo.cfg         description of compilation unit (from the build tool)
-//
-// This package does not depend on go/packages.
-// If you need a standalone tool, use multichecker,
-// which supports this mode but can also load packages
-// from source using go/packages.
-package unitchecker
-
-// TODO(adonovan):
-// - with gccgo, go build does not build standard library,
-//   so we will not get to analyze it. Yet we must in order
-//   to create base facts for, say, the fmt package for the
-//   printf checker.
-
-import (
-	"encoding/gob"
-	"encoding/json"
-	"flag"
-	"fmt"
-	"go/ast"
-	"go/build"
-	"go/importer"
-	"go/parser"
-	"go/token"
-	"go/types"
-	"io"
-	"io/ioutil"
-	"log"
-	"os"
-	"path/filepath"
-	"reflect"
-	"sort"
-	"strings"
-	"sync"
-	"time"
-
-	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/analysis/internal/analysisflags"
-	"golang.org/x/tools/go/analysis/internal/facts"
-)
-
-// A Config describes a compilation unit to be analyzed.
-// It is provided to the tool in a JSON-encoded file
-// whose name ends with ".cfg".
-type Config struct {
-	ID                        string // e.g. "fmt [fmt.test]"
-	Compiler                  string
-	Dir                       string
-	ImportPath                string
-	GoFiles                   []string
-	NonGoFiles                []string
-	IgnoredFiles              []string
-	ImportMap                 map[string]string
-	PackageFile               map[string]string
-	Standard                  map[string]bool
-	PackageVetx               map[string]string
-	VetxOnly                  bool
-	VetxOutput                string
-	SucceedOnTypecheckFailure bool
-}
-
-// Main is the main function of a vet-like analysis tool that must be
-// invoked by a build system to analyze a single package.
-//
-// The protocol required by 'go vet -vettool=...' is that the tool must support:
-//
-//      -flags          describe flags in JSON
-//      -V=full         describe executable for build caching
-//      foo.cfg         perform separate modular analyze on the single
-//                      unit described by a JSON config file foo.cfg.
-//
-func Main(analyzers ...*analysis.Analyzer) {
-	progname := filepath.Base(os.Args[0])
-	log.SetFlags(0)
-	log.SetPrefix(progname + ": ")
-
-	if err := analysis.Validate(analyzers); err != nil {
-		log.Fatal(err)
-	}
-
-	flag.Usage = func() {
-		fmt.Fprintf(os.Stderr, `%[1]s is a tool for static analysis of Go programs.
-
-Usage of %[1]s:
-	%.16[1]s unit.cfg	# execute analysis specified by config file
-	%.16[1]s help    	# general help
-	%.16[1]s help name	# help on specific analyzer and its flags
-`, progname)
-		os.Exit(1)
-	}
-
-	analyzers = analysisflags.Parse(analyzers, true)
-
-	args := flag.Args()
-	if len(args) == 0 {
-		flag.Usage()
-	}
-	if args[0] == "help" {
-		analysisflags.Help(progname, analyzers, args[1:])
-		os.Exit(0)
-	}
-	if len(args) != 1 || !strings.HasSuffix(args[0], ".cfg") {
-		log.Fatalf(`invoking "go tool vet" directly is unsupported; use "go vet"`)
-	}
-	Run(args[0], analyzers)
-}
-
-// Run reads the *.cfg file, runs the analysis,
-// and calls os.Exit with an appropriate error code.
-// It assumes flags have already been set.
-func Run(configFile string, analyzers []*analysis.Analyzer) {
-	cfg, err := readConfig(configFile)
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	fset := token.NewFileSet()
-	results, err := run(fset, cfg, analyzers)
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	// In VetxOnly mode, the analysis is run only for facts.
-	if !cfg.VetxOnly {
-		if analysisflags.JSON {
-			// JSON output
-			tree := make(analysisflags.JSONTree)
-			for _, res := range results {
-				tree.Add(fset, cfg.ID, res.a.Name, res.diagnostics, res.err)
-			}
-			tree.Print()
-		} else {
-			// plain text
-			exit := 0
-			for _, res := range results {
-				if res.err != nil {
-					log.Println(res.err)
-					exit = 1
-				}
-			}
-			for _, res := range results {
-				for _, diag := range res.diagnostics {
-					analysisflags.PrintPlain(fset, diag)
-					exit = 1
-				}
-			}
-			os.Exit(exit)
-		}
-	}
-
-	os.Exit(0)
-}
-
-func readConfig(filename string) (*Config, error) {
-	data, err := ioutil.ReadFile(filename)
-	if err != nil {
-		return nil, err
-	}
-	cfg := new(Config)
-	if err := json.Unmarshal(data, cfg); err != nil {
-		return nil, fmt.Errorf("cannot decode JSON config file %s: %v", filename, err)
-	}
-	if len(cfg.GoFiles) == 0 {
-		// The go command disallows packages with no files.
-		// The only exception is unsafe, but the go command
-		// doesn't call vet on it.
-		return nil, fmt.Errorf("package has no files: %s", cfg.ImportPath)
-	}
-	return cfg, nil
-}
-
-var importerForCompiler = func(_ *token.FileSet, compiler string, lookup importer.Lookup) types.Importer {
-	// broken legacy implementation (https://golang.org/issue/28995)
-	return importer.For(compiler, lookup)
-}
-
-func run(fset *token.FileSet, cfg *Config, analyzers []*analysis.Analyzer) ([]result, error) {
-	// Load, parse, typecheck.
-	var files []*ast.File
-	for _, name := range cfg.GoFiles {
-		f, err := parser.ParseFile(fset, name, nil, parser.ParseComments)
-		if err != nil {
-			if cfg.SucceedOnTypecheckFailure {
-				// Silently succeed; let the compiler
-				// report parse errors.
-				err = nil
-			}
-			return nil, err
-		}
-		files = append(files, f)
-	}
-	compilerImporter := importerForCompiler(fset, cfg.Compiler, func(path string) (io.ReadCloser, error) {
-		// path is a resolved package path, not an import path.
-		file, ok := cfg.PackageFile[path]
-		if !ok {
-			if cfg.Compiler == "gccgo" && cfg.Standard[path] {
-				return nil, nil // fall back to default gccgo lookup
-			}
-			return nil, fmt.Errorf("no package file for %q", path)
-		}
-		return os.Open(file)
-	})
-	importer := importerFunc(func(importPath string) (*types.Package, error) {
-		path, ok := cfg.ImportMap[importPath] // resolve vendoring, etc
-		if !ok {
-			return nil, fmt.Errorf("can't resolve import %q", path)
-		}
-		return compilerImporter.Import(path)
-	})
-	tc := &types.Config{
-		Importer: importer,
-		Sizes:    types.SizesFor("gc", build.Default.GOARCH), // assume gccgo ≡ gc?
-	}
-	info := &types.Info{
-		Types:      make(map[ast.Expr]types.TypeAndValue),
-		Defs:       make(map[*ast.Ident]types.Object),
-		Uses:       make(map[*ast.Ident]types.Object),
-		Implicits:  make(map[ast.Node]types.Object),
-		Scopes:     make(map[ast.Node]*types.Scope),
-		Selections: make(map[*ast.SelectorExpr]*types.Selection),
-	}
-	pkg, err := tc.Check(cfg.ImportPath, fset, files, info)
-	if err != nil {
-		if cfg.SucceedOnTypecheckFailure {
-			// Silently succeed; let the compiler
-			// report type errors.
-			err = nil
-		}
-		return nil, err
-	}
-
-	// Register fact types with gob.
-	// In VetxOnly mode, analyzers are only for their facts,
-	// so we can skip any analysis that neither produces facts
-	// nor depends on any analysis that produces facts.
-	// Also build a map to hold working state and result.
-	type action struct {
-		once        sync.Once
-		result      interface{}
-		err         error
-		usesFacts   bool // (transitively uses)
-		diagnostics []analysis.Diagnostic
-	}
-	actions := make(map[*analysis.Analyzer]*action)
-	var registerFacts func(a *analysis.Analyzer) bool
-	registerFacts = func(a *analysis.Analyzer) bool {
-		act, ok := actions[a]
-		if !ok {
-			act = new(action)
-			var usesFacts bool
-			for _, f := range a.FactTypes {
-				usesFacts = true
-				gob.Register(f)
-			}
-			for _, req := range a.Requires {
-				if registerFacts(req) {
-					usesFacts = true
-				}
-			}
-			act.usesFacts = usesFacts
-			actions[a] = act
-		}
-		return act.usesFacts
-	}
-	var filtered []*analysis.Analyzer
-	for _, a := range analyzers {
-		if registerFacts(a) || !cfg.VetxOnly {
-			filtered = append(filtered, a)
-		}
-	}
-	analyzers = filtered
-
-	// Read facts from imported packages.
-	read := func(path string) ([]byte, error) {
-		if vetx, ok := cfg.PackageVetx[path]; ok {
-			return ioutil.ReadFile(vetx)
-		}
-		return nil, nil // no .vetx file, no facts
-	}
-	facts, err := facts.Decode(pkg, read)
-	if err != nil {
-		return nil, err
-	}
-
-	// In parallel, execute the DAG of analyzers.
-	var exec func(a *analysis.Analyzer) *action
-	var execAll func(analyzers []*analysis.Analyzer)
-	exec = func(a *analysis.Analyzer) *action {
-		act := actions[a]
-		act.once.Do(func() {
-			execAll(a.Requires) // prefetch dependencies in parallel
-
-			// The inputs to this analysis are the
-			// results of its prerequisites.
-			inputs := make(map[*analysis.Analyzer]interface{})
-			var failed []string
-			for _, req := range a.Requires {
-				reqact := exec(req)
-				if reqact.err != nil {
-					failed = append(failed, req.String())
-					continue
-				}
-				inputs[req] = reqact.result
-			}
-
-			// Report an error if any dependency failed.
-			if failed != nil {
-				sort.Strings(failed)
-				act.err = fmt.Errorf("failed prerequisites: %s", strings.Join(failed, ", "))
-				return
-			}
-
-			factFilter := make(map[reflect.Type]bool)
-			for _, f := range a.FactTypes {
-				factFilter[reflect.TypeOf(f)] = true
-			}
-
-			pass := &analysis.Pass{
-				Analyzer:          a,
-				Fset:              fset,
-				Files:             files,
-				OtherFiles:        cfg.NonGoFiles,
-				IgnoredFiles:      cfg.IgnoredFiles,
-				Pkg:               pkg,
-				TypesInfo:         info,
-				TypesSizes:        tc.Sizes,
-				ResultOf:          inputs,
-				Report:            func(d analysis.Diagnostic) { act.diagnostics = append(act.diagnostics, d) },
-				ImportObjectFact:  facts.ImportObjectFact,
-				ExportObjectFact:  facts.ExportObjectFact,
-				AllObjectFacts:    func() []analysis.ObjectFact { return facts.AllObjectFacts(factFilter) },
-				ImportPackageFact: facts.ImportPackageFact,
-				ExportPackageFact: facts.ExportPackageFact,
-				AllPackageFacts:   func() []analysis.PackageFact { return facts.AllPackageFacts(factFilter) },
-			}
-
-			t0 := time.Now()
-			act.result, act.err = a.Run(pass)
-			if false {
-				log.Printf("analysis %s = %s", pass, time.Since(t0))
-			}
-		})
-		return act
-	}
-	execAll = func(analyzers []*analysis.Analyzer) {
-		var wg sync.WaitGroup
-		for _, a := range analyzers {
-			wg.Add(1)
-			go func(a *analysis.Analyzer) {
-				_ = exec(a)
-				wg.Done()
-			}(a)
-		}
-		wg.Wait()
-	}
-
-	execAll(analyzers)
-
-	// Return diagnostics and errors from root analyzers.
-	results := make([]result, len(analyzers))
-	for i, a := range analyzers {
-		act := actions[a]
-		results[i].a = a
-		results[i].err = act.err
-		results[i].diagnostics = act.diagnostics
-	}
-
-	data := facts.Encode()
-	if err := ioutil.WriteFile(cfg.VetxOutput, data, 0666); err != nil {
-		return nil, fmt.Errorf("failed to write analysis facts: %v", err)
-	}
-
-	return results, nil
-}
-
-type result struct {
-	a           *analysis.Analyzer
-	diagnostics []analysis.Diagnostic
-	err         error
-}
-
-type importerFunc func(path string) (*types.Package, error)
-
-func (f importerFunc) Import(path string) (*types.Package, error) { return f(path) }
diff --git a/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker112.go b/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker112.go
deleted file mode 100644
index 9051456e39..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker112.go
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build go1.12
-
-package unitchecker
-
-import "go/importer"
-
-func init() {
-	importerForCompiler = importer.ForCompiler
-}
diff --git a/vendor/golang.org/x/tools/go/analysis/validate.go b/vendor/golang.org/x/tools/go/analysis/validate.go
deleted file mode 100644
index 23e57bf02b..0000000000
--- a/vendor/golang.org/x/tools/go/analysis/validate.go
+++ /dev/null
@@ -1,130 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package analysis
-
-import (
-	"fmt"
-	"reflect"
-	"strings"
-	"unicode"
-)
-
-// Validate reports an error if any of the analyzers are misconfigured.
-// Checks include:
-// that the name is a valid identifier;
-// that the Requires graph is acyclic;
-// that analyzer fact types are unique;
-// that each fact type is a pointer.
-func Validate(analyzers []*Analyzer) error {
-	// Map each fact type to its sole generating analyzer.
-	factTypes := make(map[reflect.Type]*Analyzer)
-
-	// Traverse the Requires graph, depth first.
-	const (
-		white = iota
-		grey
-		black
-		finished
-	)
-	color := make(map[*Analyzer]uint8)
-	var visit func(a *Analyzer) error
-	visit = func(a *Analyzer) error {
-		if a == nil {
-			return fmt.Errorf("nil *Analyzer")
-		}
-		if color[a] == white {
-			color[a] = grey
-
-			// names
-			if !validIdent(a.Name) {
-				return fmt.Errorf("invalid analyzer name %q", a)
-			}
-
-			if a.Doc == "" {
-				return fmt.Errorf("analyzer %q is undocumented", a)
-			}
-
-			// fact types
-			for _, f := range a.FactTypes {
-				if f == nil {
-					return fmt.Errorf("analyzer %s has nil FactType", a)
-				}
-				t := reflect.TypeOf(f)
-				if prev := factTypes[t]; prev != nil {
-					return fmt.Errorf("fact type %s registered by two analyzers: %v, %v",
-						t, a, prev)
-				}
-				if t.Kind() != reflect.Ptr {
-					return fmt.Errorf("%s: fact type %s is not a pointer", a, t)
-				}
-				factTypes[t] = a
-			}
-
-			// recursion
-			for _, req := range a.Requires {
-				if err := visit(req); err != nil {
-					return err
-				}
-			}
-			color[a] = black
-		}
-
-		if color[a] == grey {
-			stack := []*Analyzer{a}
-			inCycle := map[string]bool{}
-			for len(stack) > 0 {
-				current := stack[len(stack)-1]
-				stack = stack[:len(stack)-1]
-				if color[current] == grey && !inCycle[current.Name] {
-					inCycle[current.Name] = true
-					stack = append(stack, current.Requires...)
-				}
-			}
-			return &CycleInRequiresGraphError{AnalyzerNames: inCycle}
-		}
-
-		return nil
-	}
-	for _, a := range analyzers {
-		if err := visit(a); err != nil {
-			return err
-		}
-	}
-
-	// Reject duplicates among analyzers.
-	// Precondition:  color[a] == black.
-	// Postcondition: color[a] == finished.
-	for _, a := range analyzers {
-		if color[a] == finished {
-			return fmt.Errorf("duplicate analyzer: %s", a.Name)
-		}
-		color[a] = finished
-	}
-
-	return nil
-}
-
-func validIdent(name string) bool {
-	for i, r := range name {
-		if !(r == '_' || unicode.IsLetter(r) || i > 0 && unicode.IsDigit(r)) {
-			return false
-		}
-	}
-	return name != ""
-}
-
-type CycleInRequiresGraphError struct {
-	AnalyzerNames map[string]bool
-}
-
-func (e *CycleInRequiresGraphError) Error() string {
-	var b strings.Builder
-	b.WriteString("cycle detected involving the following analyzers:")
-	for n := range e.AnalyzerNames {
-		b.WriteByte(' ')
-		b.WriteString(n)
-	}
-	return b.String()
-}
diff --git a/vendor/golang.org/x/tools/go/ast/astutil/enclosing.go b/vendor/golang.org/x/tools/go/ast/astutil/enclosing.go
deleted file mode 100644
index 6b7052b892..0000000000
--- a/vendor/golang.org/x/tools/go/ast/astutil/enclosing.go
+++ /dev/null
@@ -1,627 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package astutil
-
-// This file defines utilities for working with source positions.
-
-import (
-	"fmt"
-	"go/ast"
-	"go/token"
-	"sort"
-)
-
-// PathEnclosingInterval returns the node that encloses the source
-// interval [start, end), and all its ancestors up to the AST root.
-//
-// The definition of "enclosing" used by this function considers
-// additional whitespace abutting a node to be enclosed by it.
-// In this example:
-//
-//              z := x + y // add them
-//                   <-A->
-//                  <----B----->
-//
-// the ast.BinaryExpr(+) node is considered to enclose interval B
-// even though its [Pos()..End()) is actually only interval A.
-// This behaviour makes user interfaces more tolerant of imperfect
-// input.
-//
-// This function treats tokens as nodes, though they are not included
-// in the result. e.g. PathEnclosingInterval("+") returns the
-// enclosing ast.BinaryExpr("x + y").
-//
-// If start==end, the 1-char interval following start is used instead.
-//
-// The 'exact' result is true if the interval contains only path[0]
-// and perhaps some adjacent whitespace.  It is false if the interval
-// overlaps multiple children of path[0], or if it contains only
-// interior whitespace of path[0].
-// In this example:
-//
-//              z := x + y // add them
-//                <--C-->     <---E-->
-//                  ^
-//                  D
-//
-// intervals C, D and E are inexact.  C is contained by the
-// z-assignment statement, because it spans three of its children (:=,
-// x, +).  So too is the 1-char interval D, because it contains only
-// interior whitespace of the assignment.  E is considered interior
-// whitespace of the BlockStmt containing the assignment.
-//
-// Precondition: [start, end) both lie within the same file as root.
-// TODO(adonovan): return (nil, false) in this case and remove precond.
-// Requires FileSet; see loader.tokenFileContainsPos.
-//
-// Postcondition: path is never nil; it always contains at least 'root'.
-//
-func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) {
-	// fmt.Printf("EnclosingInterval %d %d\n", start, end) // debugging
-
-	// Precondition: node.[Pos..End) and adjoining whitespace contain [start, end).
-	var visit func(node ast.Node) bool
-	visit = func(node ast.Node) bool {
-		path = append(path, node)
-
-		nodePos := node.Pos()
-		nodeEnd := node.End()
-
-		// fmt.Printf("visit(%T, %d, %d)\n", node, nodePos, nodeEnd) // debugging
-
-		// Intersect [start, end) with interval of node.
-		if start < nodePos {
-			start = nodePos
-		}
-		if end > nodeEnd {
-			end = nodeEnd
-		}
-
-		// Find sole child that contains [start, end).
-		children := childrenOf(node)
-		l := len(children)
-		for i, child := range children {
-			// [childPos, childEnd) is unaugmented interval of child.
-			childPos := child.Pos()
-			childEnd := child.End()
-
-			// [augPos, augEnd) is whitespace-augmented interval of child.
-			augPos := childPos
-			augEnd := childEnd
-			if i > 0 {
-				augPos = children[i-1].End() // start of preceding whitespace
-			}
-			if i < l-1 {
-				nextChildPos := children[i+1].Pos()
-				// Does [start, end) lie between child and next child?
-				if start >= augEnd && end <= nextChildPos {
-					return false // inexact match
-				}
-				augEnd = nextChildPos // end of following whitespace
-			}
-
-			// fmt.Printf("\tchild %d: [%d..%d)\tcontains interval [%d..%d)?\n",
-			// 	i, augPos, augEnd, start, end) // debugging
-
-			// Does augmented child strictly contain [start, end)?
-			if augPos <= start && end <= augEnd {
-				_, isToken := child.(tokenNode)
-				return isToken || visit(child)
-			}
-
-			// Does [start, end) overlap multiple children?
-			// i.e. left-augmented child contains start
-			// but LR-augmented child does not contain end.
-			if start < childEnd && end > augEnd {
-				break
-			}
-		}
-
-		// No single child contained [start, end),
-		// so node is the result.  Is it exact?
-
-		// (It's tempting to put this condition before the
-		// child loop, but it gives the wrong result in the
-		// case where a node (e.g. ExprStmt) and its sole
-		// child have equal intervals.)
-		if start == nodePos && end == nodeEnd {
-			return true // exact match
-		}
-
-		return false // inexact: overlaps multiple children
-	}
-
-	if start > end {
-		start, end = end, start
-	}
-
-	if start < root.End() && end > root.Pos() {
-		if start == end {
-			end = start + 1 // empty interval => interval of size 1
-		}
-		exact = visit(root)
-
-		// Reverse the path:
-		for i, l := 0, len(path); i < l/2; i++ {
-			path[i], path[l-1-i] = path[l-1-i], path[i]
-		}
-	} else {
-		// Selection lies within whitespace preceding the
-		// first (or following the last) declaration in the file.
-		// The result nonetheless always includes the ast.File.
-		path = append(path, root)
-	}
-
-	return
-}
-
-// tokenNode is a dummy implementation of ast.Node for a single token.
-// They are used transiently by PathEnclosingInterval but never escape
-// this package.
-//
-type tokenNode struct {
-	pos token.Pos
-	end token.Pos
-}
-
-func (n tokenNode) Pos() token.Pos {
-	return n.pos
-}
-
-func (n tokenNode) End() token.Pos {
-	return n.end
-}
-
-func tok(pos token.Pos, len int) ast.Node {
-	return tokenNode{pos, pos + token.Pos(len)}
-}
-
-// childrenOf returns the direct non-nil children of ast.Node n.
-// It may include fake ast.Node implementations for bare tokens.
-// it is not safe to call (e.g.) ast.Walk on such nodes.
-//
-func childrenOf(n ast.Node) []ast.Node {
-	var children []ast.Node
-
-	// First add nodes for all true subtrees.
-	ast.Inspect(n, func(node ast.Node) bool {
-		if node == n { // push n
-			return true // recur
-		}
-		if node != nil { // push child
-			children = append(children, node)
-		}
-		return false // no recursion
-	})
-
-	// Then add fake Nodes for bare tokens.
-	switch n := n.(type) {
-	case *ast.ArrayType:
-		children = append(children,
-			tok(n.Lbrack, len("[")),
-			tok(n.Elt.End(), len("]")))
-
-	case *ast.AssignStmt:
-		children = append(children,
-			tok(n.TokPos, len(n.Tok.String())))
-
-	case *ast.BasicLit:
-		children = append(children,
-			tok(n.ValuePos, len(n.Value)))
-
-	case *ast.BinaryExpr:
-		children = append(children, tok(n.OpPos, len(n.Op.String())))
-
-	case *ast.BlockStmt:
-		children = append(children,
-			tok(n.Lbrace, len("{")),
-			tok(n.Rbrace, len("}")))
-
-	case *ast.BranchStmt:
-		children = append(children,
-			tok(n.TokPos, len(n.Tok.String())))
-
-	case *ast.CallExpr:
-		children = append(children,
-			tok(n.Lparen, len("(")),
-			tok(n.Rparen, len(")")))
-		if n.Ellipsis != 0 {
-			children = append(children, tok(n.Ellipsis, len("...")))
-		}
-
-	case *ast.CaseClause:
-		if n.List == nil {
-			children = append(children,
-				tok(n.Case, len("default")))
-		} else {
-			children = append(children,
-				tok(n.Case, len("case")))
-		}
-		children = append(children, tok(n.Colon, len(":")))
-
-	case *ast.ChanType:
-		switch n.Dir {
-		case ast.RECV:
-			children = append(children, tok(n.Begin, len("<-chan")))
-		case ast.SEND:
-			children = append(children, tok(n.Begin, len("chan<-")))
-		case ast.RECV | ast.SEND:
-			children = append(children, tok(n.Begin, len("chan")))
-		}
-
-	case *ast.CommClause:
-		if n.Comm == nil {
-			children = append(children,
-				tok(n.Case, len("default")))
-		} else {
-			children = append(children,
-				tok(n.Case, len("case")))
-		}
-		children = append(children, tok(n.Colon, len(":")))
-
-	case *ast.Comment:
-		// nop
-
-	case *ast.CommentGroup:
-		// nop
-
-	case *ast.CompositeLit:
-		children = append(children,
-			tok(n.Lbrace, len("{")),
-			tok(n.Rbrace, len("{")))
-
-	case *ast.DeclStmt:
-		// nop
-
-	case *ast.DeferStmt:
-		children = append(children,
-			tok(n.Defer, len("defer")))
-
-	case *ast.Ellipsis:
-		children = append(children,
-			tok(n.Ellipsis, len("...")))
-
-	case *ast.EmptyStmt:
-		// nop
-
-	case *ast.ExprStmt:
-		// nop
-
-	case *ast.Field:
-		// TODO(adonovan): Field.{Doc,Comment,Tag}?
-
-	case *ast.FieldList:
-		children = append(children,
-			tok(n.Opening, len("(")),
-			tok(n.Closing, len(")")))
-
-	case *ast.File:
-		// TODO test: Doc
-		children = append(children,
-			tok(n.Package, len("package")))
-
-	case *ast.ForStmt:
-		children = append(children,
-			tok(n.For, len("for")))
-
-	case *ast.FuncDecl:
-		// TODO(adonovan): FuncDecl.Comment?
-
-		// Uniquely, FuncDecl breaks the invariant that
-		// preorder traversal yields tokens in lexical order:
-		// in fact, FuncDecl.Recv precedes FuncDecl.Type.Func.
-		//
-		// As a workaround, we inline the case for FuncType
-		// here and order things correctly.
-		//
-		children = nil // discard ast.Walk(FuncDecl) info subtrees
-		children = append(children, tok(n.Type.Func, len("func")))
-		if n.Recv != nil {
-			children = append(children, n.Recv)
-		}
-		children = append(children, n.Name)
-		if n.Type.Params != nil {
-			children = append(children, n.Type.Params)
-		}
-		if n.Type.Results != nil {
-			children = append(children, n.Type.Results)
-		}
-		if n.Body != nil {
-			children = append(children, n.Body)
-		}
-
-	case *ast.FuncLit:
-		// nop
-
-	case *ast.FuncType:
-		if n.Func != 0 {
-			children = append(children,
-				tok(n.Func, len("func")))
-		}
-
-	case *ast.GenDecl:
-		children = append(children,
-			tok(n.TokPos, len(n.Tok.String())))
-		if n.Lparen != 0 {
-			children = append(children,
-				tok(n.Lparen, len("(")),
-				tok(n.Rparen, len(")")))
-		}
-
-	case *ast.GoStmt:
-		children = append(children,
-			tok(n.Go, len("go")))
-
-	case *ast.Ident:
-		children = append(children,
-			tok(n.NamePos, len(n.Name)))
-
-	case *ast.IfStmt:
-		children = append(children,
-			tok(n.If, len("if")))
-
-	case *ast.ImportSpec:
-		// TODO(adonovan): ImportSpec.{Doc,EndPos}?
-
-	case *ast.IncDecStmt:
-		children = append(children,
-			tok(n.TokPos, len(n.Tok.String())))
-
-	case *ast.IndexExpr:
-		children = append(children,
-			tok(n.Lbrack, len("{")),
-			tok(n.Rbrack, len("}")))
-
-	case *ast.InterfaceType:
-		children = append(children,
-			tok(n.Interface, len("interface")))
-
-	case *ast.KeyValueExpr:
-		children = append(children,
-			tok(n.Colon, len(":")))
-
-	case *ast.LabeledStmt:
-		children = append(children,
-			tok(n.Colon, len(":")))
-
-	case *ast.MapType:
-		children = append(children,
-			tok(n.Map, len("map")))
-
-	case *ast.ParenExpr:
-		children = append(children,
-			tok(n.Lparen, len("(")),
-			tok(n.Rparen, len(")")))
-
-	case *ast.RangeStmt:
-		children = append(children,
-			tok(n.For, len("for")),
-			tok(n.TokPos, len(n.Tok.String())))
-
-	case *ast.ReturnStmt:
-		children = append(children,
-			tok(n.Return, len("return")))
-
-	case *ast.SelectStmt:
-		children = append(children,
-			tok(n.Select, len("select")))
-
-	case *ast.SelectorExpr:
-		// nop
-
-	case *ast.SendStmt:
-		children = append(children,
-			tok(n.Arrow, len("<-")))
-
-	case *ast.SliceExpr:
-		children = append(children,
-			tok(n.Lbrack, len("[")),
-			tok(n.Rbrack, len("]")))
-
-	case *ast.StarExpr:
-		children = append(children, tok(n.Star, len("*")))
-
-	case *ast.StructType:
-		children = append(children, tok(n.Struct, len("struct")))
-
-	case *ast.SwitchStmt:
-		children = append(children, tok(n.Switch, len("switch")))
-
-	case *ast.TypeAssertExpr:
-		children = append(children,
-			tok(n.Lparen-1, len(".")),
-			tok(n.Lparen, len("(")),
-			tok(n.Rparen, len(")")))
-
-	case *ast.TypeSpec:
-		// TODO(adonovan): TypeSpec.{Doc,Comment}?
-
-	case *ast.TypeSwitchStmt:
-		children = append(children, tok(n.Switch, len("switch")))
-
-	case *ast.UnaryExpr:
-		children = append(children, tok(n.OpPos, len(n.Op.String())))
-
-	case *ast.ValueSpec:
-		// TODO(adonovan): ValueSpec.{Doc,Comment}?
-
-	case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
-		// nop
-	}
-
-	// TODO(adonovan): opt: merge the logic of ast.Inspect() into
-	// the switch above so we can make interleaved callbacks for
-	// both Nodes and Tokens in the right order and avoid the need
-	// to sort.
-	sort.Sort(byPos(children))
-
-	return children
-}
-
-type byPos []ast.Node
-
-func (sl byPos) Len() int {
-	return len(sl)
-}
-func (sl byPos) Less(i, j int) bool {
-	return sl[i].Pos() < sl[j].Pos()
-}
-func (sl byPos) Swap(i, j int) {
-	sl[i], sl[j] = sl[j], sl[i]
-}
-
-// NodeDescription returns a description of the concrete type of n suitable
-// for a user interface.
-//
-// TODO(adonovan): in some cases (e.g. Field, FieldList, Ident,
-// StarExpr) we could be much more specific given the path to the AST
-// root.  Perhaps we should do that.
-//
-func NodeDescription(n ast.Node) string {
-	switch n := n.(type) {
-	case *ast.ArrayType:
-		return "array type"
-	case *ast.AssignStmt:
-		return "assignment"
-	case *ast.BadDecl:
-		return "bad declaration"
-	case *ast.BadExpr:
-		return "bad expression"
-	case *ast.BadStmt:
-		return "bad statement"
-	case *ast.BasicLit:
-		return "basic literal"
-	case *ast.BinaryExpr:
-		return fmt.Sprintf("binary %s operation", n.Op)
-	case *ast.BlockStmt:
-		return "block"
-	case *ast.BranchStmt:
-		switch n.Tok {
-		case token.BREAK:
-			return "break statement"
-		case token.CONTINUE:
-			return "continue statement"
-		case token.GOTO:
-			return "goto statement"
-		case token.FALLTHROUGH:
-			return "fall-through statement"
-		}
-	case *ast.CallExpr:
-		if len(n.Args) == 1 && !n.Ellipsis.IsValid() {
-			return "function call (or conversion)"
-		}
-		return "function call"
-	case *ast.CaseClause:
-		return "case clause"
-	case *ast.ChanType:
-		return "channel type"
-	case *ast.CommClause:
-		return "communication clause"
-	case *ast.Comment:
-		return "comment"
-	case *ast.CommentGroup:
-		return "comment group"
-	case *ast.CompositeLit:
-		return "composite literal"
-	case *ast.DeclStmt:
-		return NodeDescription(n.Decl) + " statement"
-	case *ast.DeferStmt:
-		return "defer statement"
-	case *ast.Ellipsis:
-		return "ellipsis"
-	case *ast.EmptyStmt:
-		return "empty statement"
-	case *ast.ExprStmt:
-		return "expression statement"
-	case *ast.Field:
-		// Can be any of these:
-		// struct {x, y int}  -- struct field(s)
-		// struct {T}         -- anon struct field
-		// interface {I}      -- interface embedding
-		// interface {f()}    -- interface method
-		// func (A) func(B) C -- receiver, param(s), result(s)
-		return "field/method/parameter"
-	case *ast.FieldList:
-		return "field/method/parameter list"
-	case *ast.File:
-		return "source file"
-	case *ast.ForStmt:
-		return "for loop"
-	case *ast.FuncDecl:
-		return "function declaration"
-	case *ast.FuncLit:
-		return "function literal"
-	case *ast.FuncType:
-		return "function type"
-	case *ast.GenDecl:
-		switch n.Tok {
-		case token.IMPORT:
-			return "import declaration"
-		case token.CONST:
-			return "constant declaration"
-		case token.TYPE:
-			return "type declaration"
-		case token.VAR:
-			return "variable declaration"
-		}
-	case *ast.GoStmt:
-		return "go statement"
-	case *ast.Ident:
-		return "identifier"
-	case *ast.IfStmt:
-		return "if statement"
-	case *ast.ImportSpec:
-		return "import specification"
-	case *ast.IncDecStmt:
-		if n.Tok == token.INC {
-			return "increment statement"
-		}
-		return "decrement statement"
-	case *ast.IndexExpr:
-		return "index expression"
-	case *ast.InterfaceType:
-		return "interface type"
-	case *ast.KeyValueExpr:
-		return "key/value association"
-	case *ast.LabeledStmt:
-		return "statement label"
-	case *ast.MapType:
-		return "map type"
-	case *ast.Package:
-		return "package"
-	case *ast.ParenExpr:
-		return "parenthesized " + NodeDescription(n.X)
-	case *ast.RangeStmt:
-		return "range loop"
-	case *ast.ReturnStmt:
-		return "return statement"
-	case *ast.SelectStmt:
-		return "select statement"
-	case *ast.SelectorExpr:
-		return "selector"
-	case *ast.SendStmt:
-		return "channel send"
-	case *ast.SliceExpr:
-		return "slice expression"
-	case *ast.StarExpr:
-		return "*-operation" // load/store expr or pointer type
-	case *ast.StructType:
-		return "struct type"
-	case *ast.SwitchStmt:
-		return "switch statement"
-	case *ast.TypeAssertExpr:
-		return "type assertion"
-	case *ast.TypeSpec:
-		return "type specification"
-	case *ast.TypeSwitchStmt:
-		return "type switch"
-	case *ast.UnaryExpr:
-		return fmt.Sprintf("unary %s operation", n.Op)
-	case *ast.ValueSpec:
-		return "value specification"
-
-	}
-	panic(fmt.Sprintf("unexpected node type: %T", n))
-}
diff --git a/vendor/golang.org/x/tools/go/ast/astutil/imports.go b/vendor/golang.org/x/tools/go/ast/astutil/imports.go
deleted file mode 100644
index 2087ceec9c..0000000000
--- a/vendor/golang.org/x/tools/go/ast/astutil/imports.go
+++ /dev/null
@@ -1,482 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package astutil contains common utilities for working with the Go AST.
-package astutil // import "golang.org/x/tools/go/ast/astutil"
-
-import (
-	"fmt"
-	"go/ast"
-	"go/token"
-	"strconv"
-	"strings"
-)
-
-// AddImport adds the import path to the file f, if absent.
-func AddImport(fset *token.FileSet, f *ast.File, path string) (added bool) {
-	return AddNamedImport(fset, f, "", path)
-}
-
-// AddNamedImport adds the import with the given name and path to the file f, if absent.
-// If name is not empty, it is used to rename the import.
-//
-// For example, calling
-//	AddNamedImport(fset, f, "pathpkg", "path")
-// adds
-//	import pathpkg "path"
-func AddNamedImport(fset *token.FileSet, f *ast.File, name, path string) (added bool) {
-	if imports(f, name, path) {
-		return false
-	}
-
-	newImport := &ast.ImportSpec{
-		Path: &ast.BasicLit{
-			Kind:  token.STRING,
-			Value: strconv.Quote(path),
-		},
-	}
-	if name != "" {
-		newImport.Name = &ast.Ident{Name: name}
-	}
-
-	// Find an import decl to add to.
-	// The goal is to find an existing import
-	// whose import path has the longest shared
-	// prefix with path.
-	var (
-		bestMatch  = -1         // length of longest shared prefix
-		lastImport = -1         // index in f.Decls of the file's final import decl
-		impDecl    *ast.GenDecl // import decl containing the best match
-		impIndex   = -1         // spec index in impDecl containing the best match
-
-		isThirdPartyPath = isThirdParty(path)
-	)
-	for i, decl := range f.Decls {
-		gen, ok := decl.(*ast.GenDecl)
-		if ok && gen.Tok == token.IMPORT {
-			lastImport = i
-			// Do not add to import "C", to avoid disrupting the
-			// association with its doc comment, breaking cgo.
-			if declImports(gen, "C") {
-				continue
-			}
-
-			// Match an empty import decl if that's all that is available.
-			if len(gen.Specs) == 0 && bestMatch == -1 {
-				impDecl = gen
-			}
-
-			// Compute longest shared prefix with imports in this group and find best
-			// matched import spec.
-			// 1. Always prefer import spec with longest shared prefix.
-			// 2. While match length is 0,
-			// - for stdlib package: prefer first import spec.
-			// - for third party package: prefer first third party import spec.
-			// We cannot use last import spec as best match for third party package
-			// because grouped imports are usually placed last by goimports -local
-			// flag.
-			// See issue #19190.
-			seenAnyThirdParty := false
-			for j, spec := range gen.Specs {
-				impspec := spec.(*ast.ImportSpec)
-				p := importPath(impspec)
-				n := matchLen(p, path)
-				if n > bestMatch || (bestMatch == 0 && !seenAnyThirdParty && isThirdPartyPath) {
-					bestMatch = n
-					impDecl = gen
-					impIndex = j
-				}
-				seenAnyThirdParty = seenAnyThirdParty || isThirdParty(p)
-			}
-		}
-	}
-
-	// If no import decl found, add one after the last import.
-	if impDecl == nil {
-		impDecl = &ast.GenDecl{
-			Tok: token.IMPORT,
-		}
-		if lastImport >= 0 {
-			impDecl.TokPos = f.Decls[lastImport].End()
-		} else {
-			// There are no existing imports.
-			// Our new import, preceded by a blank line,  goes after the package declaration
-			// and after the comment, if any, that starts on the same line as the
-			// package declaration.
-			impDecl.TokPos = f.Package
-
-			file := fset.File(f.Package)
-			pkgLine := file.Line(f.Package)
-			for _, c := range f.Comments {
-				if file.Line(c.Pos()) > pkgLine {
-					break
-				}
-				// +2 for a blank line
-				impDecl.TokPos = c.End() + 2
-			}
-		}
-		f.Decls = append(f.Decls, nil)
-		copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
-		f.Decls[lastImport+1] = impDecl
-	}
-
-	// Insert new import at insertAt.
-	insertAt := 0
-	if impIndex >= 0 {
-		// insert after the found import
-		insertAt = impIndex + 1
-	}
-	impDecl.Specs = append(impDecl.Specs, nil)
-	copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
-	impDecl.Specs[insertAt] = newImport
-	pos := impDecl.Pos()
-	if insertAt > 0 {
-		// If there is a comment after an existing import, preserve the comment
-		// position by adding the new import after the comment.
-		if spec, ok := impDecl.Specs[insertAt-1].(*ast.ImportSpec); ok && spec.Comment != nil {
-			pos = spec.Comment.End()
-		} else {
-			// Assign same position as the previous import,
-			// so that the sorter sees it as being in the same block.
-			pos = impDecl.Specs[insertAt-1].Pos()
-		}
-	}
-	if newImport.Name != nil {
-		newImport.Name.NamePos = pos
-	}
-	newImport.Path.ValuePos = pos
-	newImport.EndPos = pos
-
-	// Clean up parens. impDecl contains at least one spec.
-	if len(impDecl.Specs) == 1 {
-		// Remove unneeded parens.
-		impDecl.Lparen = token.NoPos
-	} else if !impDecl.Lparen.IsValid() {
-		// impDecl needs parens added.
-		impDecl.Lparen = impDecl.Specs[0].Pos()
-	}
-
-	f.Imports = append(f.Imports, newImport)
-
-	if len(f.Decls) <= 1 {
-		return true
-	}
-
-	// Merge all the import declarations into the first one.
-	var first *ast.GenDecl
-	for i := 0; i < len(f.Decls); i++ {
-		decl := f.Decls[i]
-		gen, ok := decl.(*ast.GenDecl)
-		if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
-			continue
-		}
-		if first == nil {
-			first = gen
-			continue // Don't touch the first one.
-		}
-		// We now know there is more than one package in this import
-		// declaration. Ensure that it ends up parenthesized.
-		first.Lparen = first.Pos()
-		// Move the imports of the other import declaration to the first one.
-		for _, spec := range gen.Specs {
-			spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
-			first.Specs = append(first.Specs, spec)
-		}
-		f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
-		i--
-	}
-
-	return true
-}
-
-func isThirdParty(importPath string) bool {
-	// Third party package import path usually contains "." (".com", ".org", ...)
-	// This logic is taken from golang.org/x/tools/imports package.
-	return strings.Contains(importPath, ".")
-}
-
-// DeleteImport deletes the import path from the file f, if present.
-// If there are duplicate import declarations, all matching ones are deleted.
-func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool) {
-	return DeleteNamedImport(fset, f, "", path)
-}
-
-// DeleteNamedImport deletes the import with the given name and path from the file f, if present.
-// If there are duplicate import declarations, all matching ones are deleted.
-func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (deleted bool) {
-	var delspecs []*ast.ImportSpec
-	var delcomments []*ast.CommentGroup
-
-	// Find the import nodes that import path, if any.
-	for i := 0; i < len(f.Decls); i++ {
-		decl := f.Decls[i]
-		gen, ok := decl.(*ast.GenDecl)
-		if !ok || gen.Tok != token.IMPORT {
-			continue
-		}
-		for j := 0; j < len(gen.Specs); j++ {
-			spec := gen.Specs[j]
-			impspec := spec.(*ast.ImportSpec)
-			if importName(impspec) != name || importPath(impspec) != path {
-				continue
-			}
-
-			// We found an import spec that imports path.
-			// Delete it.
-			delspecs = append(delspecs, impspec)
-			deleted = true
-			copy(gen.Specs[j:], gen.Specs[j+1:])
-			gen.Specs = gen.Specs[:len(gen.Specs)-1]
-
-			// If this was the last import spec in this decl,
-			// delete the decl, too.
-			if len(gen.Specs) == 0 {
-				copy(f.Decls[i:], f.Decls[i+1:])
-				f.Decls = f.Decls[:len(f.Decls)-1]
-				i--
-				break
-			} else if len(gen.Specs) == 1 {
-				if impspec.Doc != nil {
-					delcomments = append(delcomments, impspec.Doc)
-				}
-				if impspec.Comment != nil {
-					delcomments = append(delcomments, impspec.Comment)
-				}
-				for _, cg := range f.Comments {
-					// Found comment on the same line as the import spec.
-					if cg.End() < impspec.Pos() && fset.Position(cg.End()).Line == fset.Position(impspec.Pos()).Line {
-						delcomments = append(delcomments, cg)
-						break
-					}
-				}
-
-				spec := gen.Specs[0].(*ast.ImportSpec)
-
-				// Move the documentation right after the import decl.
-				if spec.Doc != nil {
-					for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Doc.Pos()).Line {
-						fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
-					}
-				}
-				for _, cg := range f.Comments {
-					if cg.End() < spec.Pos() && fset.Position(cg.End()).Line == fset.Position(spec.Pos()).Line {
-						for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Pos()).Line {
-							fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
-						}
-						break
-					}
-				}
-			}
-			if j > 0 {
-				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
-				lastLine := fset.Position(lastImpspec.Path.ValuePos).Line
-				line := fset.Position(impspec.Path.ValuePos).Line
-
-				// We deleted an entry but now there may be
-				// a blank line-sized hole where the import was.
-				if line-lastLine > 1 || !gen.Rparen.IsValid() {
-					// There was a blank line immediately preceding the deleted import,
-					// so there's no need to close the hole. The right parenthesis is
-					// invalid after AddImport to an import statement without parenthesis.
-					// Do nothing.
-				} else if line != fset.File(gen.Rparen).LineCount() {
-					// There was no blank line. Close the hole.
-					fset.File(gen.Rparen).MergeLine(line)
-				}
-			}
-			j--
-		}
-	}
-
-	// Delete imports from f.Imports.
-	for i := 0; i < len(f.Imports); i++ {
-		imp := f.Imports[i]
-		for j, del := range delspecs {
-			if imp == del {
-				copy(f.Imports[i:], f.Imports[i+1:])
-				f.Imports = f.Imports[:len(f.Imports)-1]
-				copy(delspecs[j:], delspecs[j+1:])
-				delspecs = delspecs[:len(delspecs)-1]
-				i--
-				break
-			}
-		}
-	}
-
-	// Delete comments from f.Comments.
-	for i := 0; i < len(f.Comments); i++ {
-		cg := f.Comments[i]
-		for j, del := range delcomments {
-			if cg == del {
-				copy(f.Comments[i:], f.Comments[i+1:])
-				f.Comments = f.Comments[:len(f.Comments)-1]
-				copy(delcomments[j:], delcomments[j+1:])
-				delcomments = delcomments[:len(delcomments)-1]
-				i--
-				break
-			}
-		}
-	}
-
-	if len(delspecs) > 0 {
-		panic(fmt.Sprintf("deleted specs from Decls but not Imports: %v", delspecs))
-	}
-
-	return
-}
-
-// RewriteImport rewrites any import of path oldPath to path newPath.
-func RewriteImport(fset *token.FileSet, f *ast.File, oldPath, newPath string) (rewrote bool) {
-	for _, imp := range f.Imports {
-		if importPath(imp) == oldPath {
-			rewrote = true
-			// record old End, because the default is to compute
-			// it using the length of imp.Path.Value.
-			imp.EndPos = imp.End()
-			imp.Path.Value = strconv.Quote(newPath)
-		}
-	}
-	return
-}
-
-// UsesImport reports whether a given import is used.
-func UsesImport(f *ast.File, path string) (used bool) {
-	spec := importSpec(f, path)
-	if spec == nil {
-		return
-	}
-
-	name := spec.Name.String()
-	switch name {
-	case "<nil>":
-		// If the package name is not explicitly specified,
-		// make an educated guess. This is not guaranteed to be correct.
-		lastSlash := strings.LastIndex(path, "/")
-		if lastSlash == -1 {
-			name = path
-		} else {
-			name = path[lastSlash+1:]
-		}
-	case "_", ".":
-		// Not sure if this import is used - err on the side of caution.
-		return true
-	}
-
-	ast.Walk(visitFn(func(n ast.Node) {
-		sel, ok := n.(*ast.SelectorExpr)
-		if ok && isTopName(sel.X, name) {
-			used = true
-		}
-	}), f)
-
-	return
-}
-
-type visitFn func(node ast.Node)
-
-func (fn visitFn) Visit(node ast.Node) ast.Visitor {
-	fn(node)
-	return fn
-}
-
-// imports reports whether f has an import with the specified name and path.
-func imports(f *ast.File, name, path string) bool {
-	for _, s := range f.Imports {
-		if importName(s) == name && importPath(s) == path {
-			return true
-		}
-	}
-	return false
-}
-
-// importSpec returns the import spec if f imports path,
-// or nil otherwise.
-func importSpec(f *ast.File, path string) *ast.ImportSpec {
-	for _, s := range f.Imports {
-		if importPath(s) == path {
-			return s
-		}
-	}
-	return nil
-}
-
-// importName returns the name of s,
-// or "" if the import is not named.
-func importName(s *ast.ImportSpec) string {
-	if s.Name == nil {
-		return ""
-	}
-	return s.Name.Name
-}
-
-// importPath returns the unquoted import path of s,
-// or "" if the path is not properly quoted.
-func importPath(s *ast.ImportSpec) string {
-	t, err := strconv.Unquote(s.Path.Value)
-	if err != nil {
-		return ""
-	}
-	return t
-}
-
-// declImports reports whether gen contains an import of path.
-func declImports(gen *ast.GenDecl, path string) bool {
-	if gen.Tok != token.IMPORT {
-		return false
-	}
-	for _, spec := range gen.Specs {
-		impspec := spec.(*ast.ImportSpec)
-		if importPath(impspec) == path {
-			return true
-		}
-	}
-	return false
-}
-
-// matchLen returns the length of the longest path segment prefix shared by x and y.
-func matchLen(x, y string) int {
-	n := 0
-	for i := 0; i < len(x) && i < len(y) && x[i] == y[i]; i++ {
-		if x[i] == '/' {
-			n++
-		}
-	}
-	return n
-}
-
-// isTopName returns true if n is a top-level unresolved identifier with the given name.
-func isTopName(n ast.Expr, name string) bool {
-	id, ok := n.(*ast.Ident)
-	return ok && id.Name == name && id.Obj == nil
-}
-
-// Imports returns the file imports grouped by paragraph.
-func Imports(fset *token.FileSet, f *ast.File) [][]*ast.ImportSpec {
-	var groups [][]*ast.ImportSpec
-
-	for _, decl := range f.Decls {
-		genDecl, ok := decl.(*ast.GenDecl)
-		if !ok || genDecl.Tok != token.IMPORT {
-			break
-		}
-
-		group := []*ast.ImportSpec{}
-
-		var lastLine int
-		for _, spec := range genDecl.Specs {
-			importSpec := spec.(*ast.ImportSpec)
-			pos := importSpec.Path.ValuePos
-			line := fset.Position(pos).Line
-			if lastLine > 0 && pos > 0 && line-lastLine > 1 {
-				groups = append(groups, group)
-				group = []*ast.ImportSpec{}
-			}
-			group = append(group, importSpec)
-			lastLine = line
-		}
-		groups = append(groups, group)
-	}
-
-	return groups
-}
diff --git a/vendor/golang.org/x/tools/go/ast/astutil/rewrite.go b/vendor/golang.org/x/tools/go/ast/astutil/rewrite.go
deleted file mode 100644
index cf72ea990b..0000000000
--- a/vendor/golang.org/x/tools/go/ast/astutil/rewrite.go
+++ /dev/null
@@ -1,477 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package astutil
-
-import (
-	"fmt"
-	"go/ast"
-	"reflect"
-	"sort"
-)
-
-// An ApplyFunc is invoked by Apply for each node n, even if n is nil,
-// before and/or after the node's children, using a Cursor describing
-// the current node and providing operations on it.
-//
-// The return value of ApplyFunc controls the syntax tree traversal.
-// See Apply for details.
-type ApplyFunc func(*Cursor) bool
-
-// Apply traverses a syntax tree recursively, starting with root,
-// and calling pre and post for each node as described below.
-// Apply returns the syntax tree, possibly modified.
-//
-// If pre is not nil, it is called for each node before the node's
-// children are traversed (pre-order). If pre returns false, no
-// children are traversed, and post is not called for that node.
-//
-// If post is not nil, and a prior call of pre didn't return false,
-// post is called for each node after its children are traversed
-// (post-order). If post returns false, traversal is terminated and
-// Apply returns immediately.
-//
-// Only fields that refer to AST nodes are considered children;
-// i.e., token.Pos, Scopes, Objects, and fields of basic types
-// (strings, etc.) are ignored.
-//
-// Children are traversed in the order in which they appear in the
-// respective node's struct definition. A package's files are
-// traversed in the filenames' alphabetical order.
-//
-func Apply(root ast.Node, pre, post ApplyFunc) (result ast.Node) {
-	parent := &struct{ ast.Node }{root}
-	defer func() {
-		if r := recover(); r != nil && r != abort {
-			panic(r)
-		}
-		result = parent.Node
-	}()
-	a := &application{pre: pre, post: post}
-	a.apply(parent, "Node", nil, root)
-	return
-}
-
-var abort = new(int) // singleton, to signal termination of Apply
-
-// A Cursor describes a node encountered during Apply.
-// Information about the node and its parent is available
-// from the Node, Parent, Name, and Index methods.
-//
-// If p is a variable of type and value of the current parent node
-// c.Parent(), and f is the field identifier with name c.Name(),
-// the following invariants hold:
-//
-//   p.f            == c.Node()  if c.Index() <  0
-//   p.f[c.Index()] == c.Node()  if c.Index() >= 0
-//
-// The methods Replace, Delete, InsertBefore, and InsertAfter
-// can be used to change the AST without disrupting Apply.
-type Cursor struct {
-	parent ast.Node
-	name   string
-	iter   *iterator // valid if non-nil
-	node   ast.Node
-}
-
-// Node returns the current Node.
-func (c *Cursor) Node() ast.Node { return c.node }
-
-// Parent returns the parent of the current Node.
-func (c *Cursor) Parent() ast.Node { return c.parent }
-
-// Name returns the name of the parent Node field that contains the current Node.
-// If the parent is a *ast.Package and the current Node is a *ast.File, Name returns
-// the filename for the current Node.
-func (c *Cursor) Name() string { return c.name }
-
-// Index reports the index >= 0 of the current Node in the slice of Nodes that
-// contains it, or a value < 0 if the current Node is not part of a slice.
-// The index of the current node changes if InsertBefore is called while
-// processing the current node.
-func (c *Cursor) Index() int {
-	if c.iter != nil {
-		return c.iter.index
-	}
-	return -1
-}
-
-// field returns the current node's parent field value.
-func (c *Cursor) field() reflect.Value {
-	return reflect.Indirect(reflect.ValueOf(c.parent)).FieldByName(c.name)
-}
-
-// Replace replaces the current Node with n.
-// The replacement node is not walked by Apply.
-func (c *Cursor) Replace(n ast.Node) {
-	if _, ok := c.node.(*ast.File); ok {
-		file, ok := n.(*ast.File)
-		if !ok {
-			panic("attempt to replace *ast.File with non-*ast.File")
-		}
-		c.parent.(*ast.Package).Files[c.name] = file
-		return
-	}
-
-	v := c.field()
-	if i := c.Index(); i >= 0 {
-		v = v.Index(i)
-	}
-	v.Set(reflect.ValueOf(n))
-}
-
-// Delete deletes the current Node from its containing slice.
-// If the current Node is not part of a slice, Delete panics.
-// As a special case, if the current node is a package file,
-// Delete removes it from the package's Files map.
-func (c *Cursor) Delete() {
-	if _, ok := c.node.(*ast.File); ok {
-		delete(c.parent.(*ast.Package).Files, c.name)
-		return
-	}
-
-	i := c.Index()
-	if i < 0 {
-		panic("Delete node not contained in slice")
-	}
-	v := c.field()
-	l := v.Len()
-	reflect.Copy(v.Slice(i, l), v.Slice(i+1, l))
-	v.Index(l - 1).Set(reflect.Zero(v.Type().Elem()))
-	v.SetLen(l - 1)
-	c.iter.step--
-}
-
-// InsertAfter inserts n after the current Node in its containing slice.
-// If the current Node is not part of a slice, InsertAfter panics.
-// Apply does not walk n.
-func (c *Cursor) InsertAfter(n ast.Node) {
-	i := c.Index()
-	if i < 0 {
-		panic("InsertAfter node not contained in slice")
-	}
-	v := c.field()
-	v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
-	l := v.Len()
-	reflect.Copy(v.Slice(i+2, l), v.Slice(i+1, l))
-	v.Index(i + 1).Set(reflect.ValueOf(n))
-	c.iter.step++
-}
-
-// InsertBefore inserts n before the current Node in its containing slice.
-// If the current Node is not part of a slice, InsertBefore panics.
-// Apply will not walk n.
-func (c *Cursor) InsertBefore(n ast.Node) {
-	i := c.Index()
-	if i < 0 {
-		panic("InsertBefore node not contained in slice")
-	}
-	v := c.field()
-	v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
-	l := v.Len()
-	reflect.Copy(v.Slice(i+1, l), v.Slice(i, l))
-	v.Index(i).Set(reflect.ValueOf(n))
-	c.iter.index++
-}
-
-// application carries all the shared data so we can pass it around cheaply.
-type application struct {
-	pre, post ApplyFunc
-	cursor    Cursor
-	iter      iterator
-}
-
-func (a *application) apply(parent ast.Node, name string, iter *iterator, n ast.Node) {
-	// convert typed nil into untyped nil
-	if v := reflect.ValueOf(n); v.Kind() == reflect.Ptr && v.IsNil() {
-		n = nil
-	}
-
-	// avoid heap-allocating a new cursor for each apply call; reuse a.cursor instead
-	saved := a.cursor
-	a.cursor.parent = parent
-	a.cursor.name = name
-	a.cursor.iter = iter
-	a.cursor.node = n
-
-	if a.pre != nil && !a.pre(&a.cursor) {
-		a.cursor = saved
-		return
-	}
-
-	// walk children
-	// (the order of the cases matches the order of the corresponding node types in go/ast)
-	switch n := n.(type) {
-	case nil:
-		// nothing to do
-
-	// Comments and fields
-	case *ast.Comment:
-		// nothing to do
-
-	case *ast.CommentGroup:
-		if n != nil {
-			a.applyList(n, "List")
-		}
-
-	case *ast.Field:
-		a.apply(n, "Doc", nil, n.Doc)
-		a.applyList(n, "Names")
-		a.apply(n, "Type", nil, n.Type)
-		a.apply(n, "Tag", nil, n.Tag)
-		a.apply(n, "Comment", nil, n.Comment)
-
-	case *ast.FieldList:
-		a.applyList(n, "List")
-
-	// Expressions
-	case *ast.BadExpr, *ast.Ident, *ast.BasicLit:
-		// nothing to do
-
-	case *ast.Ellipsis:
-		a.apply(n, "Elt", nil, n.Elt)
-
-	case *ast.FuncLit:
-		a.apply(n, "Type", nil, n.Type)
-		a.apply(n, "Body", nil, n.Body)
-
-	case *ast.CompositeLit:
-		a.apply(n, "Type", nil, n.Type)
-		a.applyList(n, "Elts")
-
-	case *ast.ParenExpr:
-		a.apply(n, "X", nil, n.X)
-
-	case *ast.SelectorExpr:
-		a.apply(n, "X", nil, n.X)
-		a.apply(n, "Sel", nil, n.Sel)
-
-	case *ast.IndexExpr:
-		a.apply(n, "X", nil, n.X)
-		a.apply(n, "Index", nil, n.Index)
-
-	case *ast.SliceExpr:
-		a.apply(n, "X", nil, n.X)
-		a.apply(n, "Low", nil, n.Low)
-		a.apply(n, "High", nil, n.High)
-		a.apply(n, "Max", nil, n.Max)
-
-	case *ast.TypeAssertExpr:
-		a.apply(n, "X", nil, n.X)
-		a.apply(n, "Type", nil, n.Type)
-
-	case *ast.CallExpr:
-		a.apply(n, "Fun", nil, n.Fun)
-		a.applyList(n, "Args")
-
-	case *ast.StarExpr:
-		a.apply(n, "X", nil, n.X)
-
-	case *ast.UnaryExpr:
-		a.apply(n, "X", nil, n.X)
-
-	case *ast.BinaryExpr:
-		a.apply(n, "X", nil, n.X)
-		a.apply(n, "Y", nil, n.Y)
-
-	case *ast.KeyValueExpr:
-		a.apply(n, "Key", nil, n.Key)
-		a.apply(n, "Value", nil, n.Value)
-
-	// Types
-	case *ast.ArrayType:
-		a.apply(n, "Len", nil, n.Len)
-		a.apply(n, "Elt", nil, n.Elt)
-
-	case *ast.StructType:
-		a.apply(n, "Fields", nil, n.Fields)
-
-	case *ast.FuncType:
-		a.apply(n, "Params", nil, n.Params)
-		a.apply(n, "Results", nil, n.Results)
-
-	case *ast.InterfaceType:
-		a.apply(n, "Methods", nil, n.Methods)
-
-	case *ast.MapType:
-		a.apply(n, "Key", nil, n.Key)
-		a.apply(n, "Value", nil, n.Value)
-
-	case *ast.ChanType:
-		a.apply(n, "Value", nil, n.Value)
-
-	// Statements
-	case *ast.BadStmt:
-		// nothing to do
-
-	case *ast.DeclStmt:
-		a.apply(n, "Decl", nil, n.Decl)
-
-	case *ast.EmptyStmt:
-		// nothing to do
-
-	case *ast.LabeledStmt:
-		a.apply(n, "Label", nil, n.Label)
-		a.apply(n, "Stmt", nil, n.Stmt)
-
-	case *ast.ExprStmt:
-		a.apply(n, "X", nil, n.X)
-
-	case *ast.SendStmt:
-		a.apply(n, "Chan", nil, n.Chan)
-		a.apply(n, "Value", nil, n.Value)
-
-	case *ast.IncDecStmt:
-		a.apply(n, "X", nil, n.X)
-
-	case *ast.AssignStmt:
-		a.applyList(n, "Lhs")
-		a.applyList(n, "Rhs")
-
-	case *ast.GoStmt:
-		a.apply(n, "Call", nil, n.Call)
-
-	case *ast.DeferStmt:
-		a.apply(n, "Call", nil, n.Call)
-
-	case *ast.ReturnStmt:
-		a.applyList(n, "Results")
-
-	case *ast.BranchStmt:
-		a.apply(n, "Label", nil, n.Label)
-
-	case *ast.BlockStmt:
-		a.applyList(n, "List")
-
-	case *ast.IfStmt:
-		a.apply(n, "Init", nil, n.Init)
-		a.apply(n, "Cond", nil, n.Cond)
-		a.apply(n, "Body", nil, n.Body)
-		a.apply(n, "Else", nil, n.Else)
-
-	case *ast.CaseClause:
-		a.applyList(n, "List")
-		a.applyList(n, "Body")
-
-	case *ast.SwitchStmt:
-		a.apply(n, "Init", nil, n.Init)
-		a.apply(n, "Tag", nil, n.Tag)
-		a.apply(n, "Body", nil, n.Body)
-
-	case *ast.TypeSwitchStmt:
-		a.apply(n, "Init", nil, n.Init)
-		a.apply(n, "Assign", nil, n.Assign)
-		a.apply(n, "Body", nil, n.Body)
-
-	case *ast.CommClause:
-		a.apply(n, "Comm", nil, n.Comm)
-		a.applyList(n, "Body")
-
-	case *ast.SelectStmt:
-		a.apply(n, "Body", nil, n.Body)
-
-	case *ast.ForStmt:
-		a.apply(n, "Init", nil, n.Init)
-		a.apply(n, "Cond", nil, n.Cond)
-		a.apply(n, "Post", nil, n.Post)
-		a.apply(n, "Body", nil, n.Body)
-
-	case *ast.RangeStmt:
-		a.apply(n, "Key", nil, n.Key)
-		a.apply(n, "Value", nil, n.Value)
-		a.apply(n, "X", nil, n.X)
-		a.apply(n, "Body", nil, n.Body)
-
-	// Declarations
-	case *ast.ImportSpec:
-		a.apply(n, "Doc", nil, n.Doc)
-		a.apply(n, "Name", nil, n.Name)
-		a.apply(n, "Path", nil, n.Path)
-		a.apply(n, "Comment", nil, n.Comment)
-
-	case *ast.ValueSpec:
-		a.apply(n, "Doc", nil, n.Doc)
-		a.applyList(n, "Names")
-		a.apply(n, "Type", nil, n.Type)
-		a.applyList(n, "Values")
-		a.apply(n, "Comment", nil, n.Comment)
-
-	case *ast.TypeSpec:
-		a.apply(n, "Doc", nil, n.Doc)
-		a.apply(n, "Name", nil, n.Name)
-		a.apply(n, "Type", nil, n.Type)
-		a.apply(n, "Comment", nil, n.Comment)
-
-	case *ast.BadDecl:
-		// nothing to do
-
-	case *ast.GenDecl:
-		a.apply(n, "Doc", nil, n.Doc)
-		a.applyList(n, "Specs")
-
-	case *ast.FuncDecl:
-		a.apply(n, "Doc", nil, n.Doc)
-		a.apply(n, "Recv", nil, n.Recv)
-		a.apply(n, "Name", nil, n.Name)
-		a.apply(n, "Type", nil, n.Type)
-		a.apply(n, "Body", nil, n.Body)
-
-	// Files and packages
-	case *ast.File:
-		a.apply(n, "Doc", nil, n.Doc)
-		a.apply(n, "Name", nil, n.Name)
-		a.applyList(n, "Decls")
-		// Don't walk n.Comments; they have either been walked already if
-		// they are Doc comments, or they can be easily walked explicitly.
-
-	case *ast.Package:
-		// collect and sort names for reproducible behavior
-		var names []string
-		for name := range n.Files {
-			names = append(names, name)
-		}
-		sort.Strings(names)
-		for _, name := range names {
-			a.apply(n, name, nil, n.Files[name])
-		}
-
-	default:
-		panic(fmt.Sprintf("Apply: unexpected node type %T", n))
-	}
-
-	if a.post != nil && !a.post(&a.cursor) {
-		panic(abort)
-	}
-
-	a.cursor = saved
-}
-
-// An iterator controls iteration over a slice of nodes.
-type iterator struct {
-	index, step int
-}
-
-func (a *application) applyList(parent ast.Node, name string) {
-	// avoid heap-allocating a new iterator for each applyList call; reuse a.iter instead
-	saved := a.iter
-	a.iter.index = 0
-	for {
-		// must reload parent.name each time, since cursor modifications might change it
-		v := reflect.Indirect(reflect.ValueOf(parent)).FieldByName(name)
-		if a.iter.index >= v.Len() {
-			break
-		}
-
-		// element x may be nil in a bad AST - be cautious
-		var x ast.Node
-		if e := v.Index(a.iter.index); e.IsValid() {
-			x = e.Interface().(ast.Node)
-		}
-
-		a.iter.step = 1
-		a.apply(parent, name, &a.iter, x)
-		a.iter.index += a.iter.step
-	}
-	a.iter = saved
-}
diff --git a/vendor/golang.org/x/tools/go/ast/astutil/util.go b/vendor/golang.org/x/tools/go/ast/astutil/util.go
deleted file mode 100644
index 919d5305ab..0000000000
--- a/vendor/golang.org/x/tools/go/ast/astutil/util.go
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package astutil
-
-import "go/ast"
-
-// Unparen returns e with any enclosing parentheses stripped.
-func Unparen(e ast.Expr) ast.Expr {
-	for {
-		p, ok := e.(*ast.ParenExpr)
-		if !ok {
-			return e
-		}
-		e = p.X
-	}
-}
diff --git a/vendor/golang.org/x/tools/go/buildutil/allpackages.go b/vendor/golang.org/x/tools/go/buildutil/allpackages.go
deleted file mode 100644
index c0cb03e7be..0000000000
--- a/vendor/golang.org/x/tools/go/buildutil/allpackages.go
+++ /dev/null
@@ -1,198 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package buildutil provides utilities related to the go/build
-// package in the standard library.
-//
-// All I/O is done via the build.Context file system interface, which must
-// be concurrency-safe.
-package buildutil // import "golang.org/x/tools/go/buildutil"
-
-import (
-	"go/build"
-	"os"
-	"path/filepath"
-	"sort"
-	"strings"
-	"sync"
-)
-
-// AllPackages returns the package path of each Go package in any source
-// directory of the specified build context (e.g. $GOROOT or an element
-// of $GOPATH).  Errors are ignored.  The results are sorted.
-// All package paths are canonical, and thus may contain "/vendor/".
-//
-// The result may include import paths for directories that contain no
-// *.go files, such as "archive" (in $GOROOT/src).
-//
-// All I/O is done via the build.Context file system interface,
-// which must be concurrency-safe.
-//
-func AllPackages(ctxt *build.Context) []string {
-	var list []string
-	ForEachPackage(ctxt, func(pkg string, _ error) {
-		list = append(list, pkg)
-	})
-	sort.Strings(list)
-	return list
-}
-
-// ForEachPackage calls the found function with the package path of
-// each Go package it finds in any source directory of the specified
-// build context (e.g. $GOROOT or an element of $GOPATH).
-// All package paths are canonical, and thus may contain "/vendor/".
-//
-// If the package directory exists but could not be read, the second
-// argument to the found function provides the error.
-//
-// All I/O is done via the build.Context file system interface,
-// which must be concurrency-safe.
-//
-func ForEachPackage(ctxt *build.Context, found func(importPath string, err error)) {
-	ch := make(chan item)
-
-	var wg sync.WaitGroup
-	for _, root := range ctxt.SrcDirs() {
-		root := root
-		wg.Add(1)
-		go func() {
-			allPackages(ctxt, root, ch)
-			wg.Done()
-		}()
-	}
-	go func() {
-		wg.Wait()
-		close(ch)
-	}()
-
-	// All calls to found occur in the caller's goroutine.
-	for i := range ch {
-		found(i.importPath, i.err)
-	}
-}
-
-type item struct {
-	importPath string
-	err        error // (optional)
-}
-
-// We use a process-wide counting semaphore to limit
-// the number of parallel calls to ReadDir.
-var ioLimit = make(chan bool, 20)
-
-func allPackages(ctxt *build.Context, root string, ch chan<- item) {
-	root = filepath.Clean(root) + string(os.PathSeparator)
-
-	var wg sync.WaitGroup
-
-	var walkDir func(dir string)
-	walkDir = func(dir string) {
-		// Avoid .foo, _foo, and testdata directory trees.
-		base := filepath.Base(dir)
-		if base == "" || base[0] == '.' || base[0] == '_' || base == "testdata" {
-			return
-		}
-
-		pkg := filepath.ToSlash(strings.TrimPrefix(dir, root))
-
-		// Prune search if we encounter any of these import paths.
-		switch pkg {
-		case "builtin":
-			return
-		}
-
-		ioLimit <- true
-		files, err := ReadDir(ctxt, dir)
-		<-ioLimit
-		if pkg != "" || err != nil {
-			ch <- item{pkg, err}
-		}
-		for _, fi := range files {
-			fi := fi
-			if fi.IsDir() {
-				wg.Add(1)
-				go func() {
-					walkDir(filepath.Join(dir, fi.Name()))
-					wg.Done()
-				}()
-			}
-		}
-	}
-
-	walkDir(root)
-	wg.Wait()
-}
-
-// ExpandPatterns returns the set of packages matched by patterns,
-// which may have the following forms:
-//
-//		golang.org/x/tools/cmd/guru     # a single package
-//		golang.org/x/tools/...          # all packages beneath dir
-//		...                             # the entire workspace.
-//
-// Order is significant: a pattern preceded by '-' removes matching
-// packages from the set.  For example, these patterns match all encoding
-// packages except encoding/xml:
-//
-// 	encoding/... -encoding/xml
-//
-// A trailing slash in a pattern is ignored.  (Path components of Go
-// package names are separated by slash, not the platform's path separator.)
-//
-func ExpandPatterns(ctxt *build.Context, patterns []string) map[string]bool {
-	// TODO(adonovan): support other features of 'go list':
-	// - "std"/"cmd"/"all" meta-packages
-	// - "..." not at the end of a pattern
-	// - relative patterns using "./" or "../" prefix
-
-	pkgs := make(map[string]bool)
-	doPkg := func(pkg string, neg bool) {
-		if neg {
-			delete(pkgs, pkg)
-		} else {
-			pkgs[pkg] = true
-		}
-	}
-
-	// Scan entire workspace if wildcards are present.
-	// TODO(adonovan): opt: scan only the necessary subtrees of the workspace.
-	var all []string
-	for _, arg := range patterns {
-		if strings.HasSuffix(arg, "...") {
-			all = AllPackages(ctxt)
-			break
-		}
-	}
-
-	for _, arg := range patterns {
-		if arg == "" {
-			continue
-		}
-
-		neg := arg[0] == '-'
-		if neg {
-			arg = arg[1:]
-		}
-
-		if arg == "..." {
-			// ... matches all packages
-			for _, pkg := range all {
-				doPkg(pkg, neg)
-			}
-		} else if dir := strings.TrimSuffix(arg, "/..."); dir != arg {
-			// dir/... matches all packages beneath dir
-			for _, pkg := range all {
-				if strings.HasPrefix(pkg, dir) &&
-					(len(pkg) == len(dir) || pkg[len(dir)] == '/') {
-					doPkg(pkg, neg)
-				}
-			}
-		} else {
-			// single package
-			doPkg(strings.TrimSuffix(arg, "/"), neg)
-		}
-	}
-
-	return pkgs
-}
diff --git a/vendor/golang.org/x/tools/go/buildutil/fakecontext.go b/vendor/golang.org/x/tools/go/buildutil/fakecontext.go
deleted file mode 100644
index 5fc672fd51..0000000000
--- a/vendor/golang.org/x/tools/go/buildutil/fakecontext.go
+++ /dev/null
@@ -1,113 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package buildutil
-
-import (
-	"fmt"
-	"go/build"
-	"io"
-	"io/ioutil"
-	"os"
-	"path"
-	"path/filepath"
-	"sort"
-	"strings"
-	"time"
-)
-
-// FakeContext returns a build.Context for the fake file tree specified
-// by pkgs, which maps package import paths to a mapping from file base
-// names to contents.
-//
-// The fake Context has a GOROOT of "/go" and no GOPATH, and overrides
-// the necessary file access methods to read from memory instead of the
-// real file system.
-//
-// Unlike a real file tree, the fake one has only two levels---packages
-// and files---so ReadDir("/go/src/") returns all packages under
-// /go/src/ including, for instance, "math" and "math/big".
-// ReadDir("/go/src/math/big") would return all the files in the
-// "math/big" package.
-//
-func FakeContext(pkgs map[string]map[string]string) *build.Context {
-	clean := func(filename string) string {
-		f := path.Clean(filepath.ToSlash(filename))
-		// Removing "/go/src" while respecting segment
-		// boundaries has this unfortunate corner case:
-		if f == "/go/src" {
-			return ""
-		}
-		return strings.TrimPrefix(f, "/go/src/")
-	}
-
-	ctxt := build.Default // copy
-	ctxt.GOROOT = "/go"
-	ctxt.GOPATH = ""
-	ctxt.Compiler = "gc"
-	ctxt.IsDir = func(dir string) bool {
-		dir = clean(dir)
-		if dir == "" {
-			return true // needed by (*build.Context).SrcDirs
-		}
-		return pkgs[dir] != nil
-	}
-	ctxt.ReadDir = func(dir string) ([]os.FileInfo, error) {
-		dir = clean(dir)
-		var fis []os.FileInfo
-		if dir == "" {
-			// enumerate packages
-			for importPath := range pkgs {
-				fis = append(fis, fakeDirInfo(importPath))
-			}
-		} else {
-			// enumerate files of package
-			for basename := range pkgs[dir] {
-				fis = append(fis, fakeFileInfo(basename))
-			}
-		}
-		sort.Sort(byName(fis))
-		return fis, nil
-	}
-	ctxt.OpenFile = func(filename string) (io.ReadCloser, error) {
-		filename = clean(filename)
-		dir, base := path.Split(filename)
-		content, ok := pkgs[path.Clean(dir)][base]
-		if !ok {
-			return nil, fmt.Errorf("file not found: %s", filename)
-		}
-		return ioutil.NopCloser(strings.NewReader(content)), nil
-	}
-	ctxt.IsAbsPath = func(path string) bool {
-		path = filepath.ToSlash(path)
-		// Don't rely on the default (filepath.Path) since on
-		// Windows, it reports virtual paths as non-absolute.
-		return strings.HasPrefix(path, "/")
-	}
-	return &ctxt
-}
-
-type byName []os.FileInfo
-
-func (s byName) Len() int           { return len(s) }
-func (s byName) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
-func (s byName) Less(i, j int) bool { return s[i].Name() < s[j].Name() }
-
-type fakeFileInfo string
-
-func (fi fakeFileInfo) Name() string    { return string(fi) }
-func (fakeFileInfo) Sys() interface{}   { return nil }
-func (fakeFileInfo) ModTime() time.Time { return time.Time{} }
-func (fakeFileInfo) IsDir() bool        { return false }
-func (fakeFileInfo) Size() int64        { return 0 }
-func (fakeFileInfo) Mode() os.FileMode  { return 0644 }
-
-type fakeDirInfo string
-
-func (fd fakeDirInfo) Name() string    { return string(fd) }
-func (fakeDirInfo) Sys() interface{}   { return nil }
-func (fakeDirInfo) ModTime() time.Time { return time.Time{} }
-func (fakeDirInfo) IsDir() bool        { return true }
-func (fakeDirInfo) Size() int64        { return 0 }
-func (fakeDirInfo) Mode() os.FileMode  { return 0755 }
diff --git a/vendor/golang.org/x/tools/go/buildutil/overlay.go b/vendor/golang.org/x/tools/go/buildutil/overlay.go
deleted file mode 100644
index 8e239086bd..0000000000
--- a/vendor/golang.org/x/tools/go/buildutil/overlay.go
+++ /dev/null
@@ -1,103 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package buildutil
-
-import (
-	"bufio"
-	"bytes"
-	"fmt"
-	"go/build"
-	"io"
-	"io/ioutil"
-	"path/filepath"
-	"strconv"
-	"strings"
-)
-
-// OverlayContext overlays a build.Context with additional files from
-// a map. Files in the map take precedence over other files.
-//
-// In addition to plain string comparison, two file names are
-// considered equal if their base names match and their directory
-// components point at the same directory on the file system. That is,
-// symbolic links are followed for directories, but not files.
-//
-// A common use case for OverlayContext is to allow editors to pass in
-// a set of unsaved, modified files.
-//
-// Currently, only the Context.OpenFile function will respect the
-// overlay. This may change in the future.
-func OverlayContext(orig *build.Context, overlay map[string][]byte) *build.Context {
-	// TODO(dominikh): Implement IsDir, HasSubdir and ReadDir
-
-	rc := func(data []byte) (io.ReadCloser, error) {
-		return ioutil.NopCloser(bytes.NewBuffer(data)), nil
-	}
-
-	copy := *orig // make a copy
-	ctxt := &copy
-	ctxt.OpenFile = func(path string) (io.ReadCloser, error) {
-		// Fast path: names match exactly.
-		if content, ok := overlay[path]; ok {
-			return rc(content)
-		}
-
-		// Slow path: check for same file under a different
-		// alias, perhaps due to a symbolic link.
-		for filename, content := range overlay {
-			if sameFile(path, filename) {
-				return rc(content)
-			}
-		}
-
-		return OpenFile(orig, path)
-	}
-	return ctxt
-}
-
-// ParseOverlayArchive parses an archive containing Go files and their
-// contents. The result is intended to be used with OverlayContext.
-//
-//
-// Archive format
-//
-// The archive consists of a series of files. Each file consists of a
-// name, a decimal file size and the file contents, separated by
-// newlines. No newline follows after the file contents.
-func ParseOverlayArchive(archive io.Reader) (map[string][]byte, error) {
-	overlay := make(map[string][]byte)
-	r := bufio.NewReader(archive)
-	for {
-		// Read file name.
-		filename, err := r.ReadString('\n')
-		if err != nil {
-			if err == io.EOF {
-				break // OK
-			}
-			return nil, fmt.Errorf("reading archive file name: %v", err)
-		}
-		filename = filepath.Clean(strings.TrimSpace(filename))
-
-		// Read file size.
-		sz, err := r.ReadString('\n')
-		if err != nil {
-			return nil, fmt.Errorf("reading size of archive file %s: %v", filename, err)
-		}
-		sz = strings.TrimSpace(sz)
-		size, err := strconv.ParseUint(sz, 10, 32)
-		if err != nil {
-			return nil, fmt.Errorf("parsing size of archive file %s: %v", filename, err)
-		}
-
-		// Read file content.
-		content := make([]byte, size)
-		if _, err := io.ReadFull(r, content); err != nil {
-			return nil, fmt.Errorf("reading archive file %s: %v", filename, err)
-		}
-		overlay[filename] = content
-	}
-
-	return overlay, nil
-}
diff --git a/vendor/golang.org/x/tools/go/buildutil/tags.go b/vendor/golang.org/x/tools/go/buildutil/tags.go
deleted file mode 100644
index 6da0ce4848..0000000000
--- a/vendor/golang.org/x/tools/go/buildutil/tags.go
+++ /dev/null
@@ -1,79 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package buildutil
-
-// This logic was copied from stringsFlag from $GOROOT/src/cmd/go/build.go.
-
-import "fmt"
-
-const TagsFlagDoc = "a list of `build tags` to consider satisfied during the build. " +
-	"For more information about build tags, see the description of " +
-	"build constraints in the documentation for the go/build package"
-
-// TagsFlag is an implementation of the flag.Value and flag.Getter interfaces that parses
-// a flag value in the same manner as go build's -tags flag and
-// populates a []string slice.
-//
-// See $GOROOT/src/go/build/doc.go for description of build tags.
-// See $GOROOT/src/cmd/go/doc.go for description of 'go build -tags' flag.
-//
-// Example:
-// 	flag.Var((*buildutil.TagsFlag)(&build.Default.BuildTags), "tags", buildutil.TagsFlagDoc)
-type TagsFlag []string
-
-func (v *TagsFlag) Set(s string) error {
-	var err error
-	*v, err = splitQuotedFields(s)
-	if *v == nil {
-		*v = []string{}
-	}
-	return err
-}
-
-func (v *TagsFlag) Get() interface{} { return *v }
-
-func splitQuotedFields(s string) ([]string, error) {
-	// Split fields allowing '' or "" around elements.
-	// Quotes further inside the string do not count.
-	var f []string
-	for len(s) > 0 {
-		for len(s) > 0 && isSpaceByte(s[0]) {
-			s = s[1:]
-		}
-		if len(s) == 0 {
-			break
-		}
-		// Accepted quoted string. No unescaping inside.
-		if s[0] == '"' || s[0] == '\'' {
-			quote := s[0]
-			s = s[1:]
-			i := 0
-			for i < len(s) && s[i] != quote {
-				i++
-			}
-			if i >= len(s) {
-				return nil, fmt.Errorf("unterminated %c string", quote)
-			}
-			f = append(f, s[:i])
-			s = s[i+1:]
-			continue
-		}
-		i := 0
-		for i < len(s) && !isSpaceByte(s[i]) {
-			i++
-		}
-		f = append(f, s[:i])
-		s = s[i:]
-	}
-	return f, nil
-}
-
-func (v *TagsFlag) String() string {
-	return "<tagsFlag>"
-}
-
-func isSpaceByte(c byte) bool {
-	return c == ' ' || c == '\t' || c == '\n' || c == '\r'
-}
diff --git a/vendor/golang.org/x/tools/go/buildutil/util.go b/vendor/golang.org/x/tools/go/buildutil/util.go
deleted file mode 100644
index fc923d7a70..0000000000
--- a/vendor/golang.org/x/tools/go/buildutil/util.go
+++ /dev/null
@@ -1,212 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package buildutil
-
-import (
-	"fmt"
-	"go/ast"
-	"go/build"
-	"go/parser"
-	"go/token"
-	"io"
-	"io/ioutil"
-	"os"
-	"path"
-	"path/filepath"
-	"strings"
-)
-
-// ParseFile behaves like parser.ParseFile,
-// but uses the build context's file system interface, if any.
-//
-// If file is not absolute (as defined by IsAbsPath), the (dir, file)
-// components are joined using JoinPath; dir must be absolute.
-//
-// The displayPath function, if provided, is used to transform the
-// filename that will be attached to the ASTs.
-//
-// TODO(adonovan): call this from go/loader.parseFiles when the tree thaws.
-//
-func ParseFile(fset *token.FileSet, ctxt *build.Context, displayPath func(string) string, dir string, file string, mode parser.Mode) (*ast.File, error) {
-	if !IsAbsPath(ctxt, file) {
-		file = JoinPath(ctxt, dir, file)
-	}
-	rd, err := OpenFile(ctxt, file)
-	if err != nil {
-		return nil, err
-	}
-	defer rd.Close() // ignore error
-	if displayPath != nil {
-		file = displayPath(file)
-	}
-	return parser.ParseFile(fset, file, rd, mode)
-}
-
-// ContainingPackage returns the package containing filename.
-//
-// If filename is not absolute, it is interpreted relative to working directory dir.
-// All I/O is via the build context's file system interface, if any.
-//
-// The '...Files []string' fields of the resulting build.Package are not
-// populated (build.FindOnly mode).
-//
-func ContainingPackage(ctxt *build.Context, dir, filename string) (*build.Package, error) {
-	if !IsAbsPath(ctxt, filename) {
-		filename = JoinPath(ctxt, dir, filename)
-	}
-
-	// We must not assume the file tree uses
-	// "/" always,
-	// `\` always,
-	// or os.PathSeparator (which varies by platform),
-	// but to make any progress, we are forced to assume that
-	// paths will not use `\` unless the PathSeparator
-	// is also `\`, thus we can rely on filepath.ToSlash for some sanity.
-
-	dirSlash := path.Dir(filepath.ToSlash(filename)) + "/"
-
-	// We assume that no source root (GOPATH[i] or GOROOT) contains any other.
-	for _, srcdir := range ctxt.SrcDirs() {
-		srcdirSlash := filepath.ToSlash(srcdir) + "/"
-		if importPath, ok := HasSubdir(ctxt, srcdirSlash, dirSlash); ok {
-			return ctxt.Import(importPath, dir, build.FindOnly)
-		}
-	}
-
-	return nil, fmt.Errorf("can't find package containing %s", filename)
-}
-
-// -- Effective methods of file system interface -------------------------
-
-// (go/build.Context defines these as methods, but does not export them.)
-
-// hasSubdir calls ctxt.HasSubdir (if not nil) or else uses
-// the local file system to answer the question.
-func HasSubdir(ctxt *build.Context, root, dir string) (rel string, ok bool) {
-	if f := ctxt.HasSubdir; f != nil {
-		return f(root, dir)
-	}
-
-	// Try using paths we received.
-	if rel, ok = hasSubdir(root, dir); ok {
-		return
-	}
-
-	// Try expanding symlinks and comparing
-	// expanded against unexpanded and
-	// expanded against expanded.
-	rootSym, _ := filepath.EvalSymlinks(root)
-	dirSym, _ := filepath.EvalSymlinks(dir)
-
-	if rel, ok = hasSubdir(rootSym, dir); ok {
-		return
-	}
-	if rel, ok = hasSubdir(root, dirSym); ok {
-		return
-	}
-	return hasSubdir(rootSym, dirSym)
-}
-
-func hasSubdir(root, dir string) (rel string, ok bool) {
-	const sep = string(filepath.Separator)
-	root = filepath.Clean(root)
-	if !strings.HasSuffix(root, sep) {
-		root += sep
-	}
-
-	dir = filepath.Clean(dir)
-	if !strings.HasPrefix(dir, root) {
-		return "", false
-	}
-
-	return filepath.ToSlash(dir[len(root):]), true
-}
-
-// FileExists returns true if the specified file exists,
-// using the build context's file system interface.
-func FileExists(ctxt *build.Context, path string) bool {
-	if ctxt.OpenFile != nil {
-		r, err := ctxt.OpenFile(path)
-		if err != nil {
-			return false
-		}
-		r.Close() // ignore error
-		return true
-	}
-	_, err := os.Stat(path)
-	return err == nil
-}
-
-// OpenFile behaves like os.Open,
-// but uses the build context's file system interface, if any.
-func OpenFile(ctxt *build.Context, path string) (io.ReadCloser, error) {
-	if ctxt.OpenFile != nil {
-		return ctxt.OpenFile(path)
-	}
-	return os.Open(path)
-}
-
-// IsAbsPath behaves like filepath.IsAbs,
-// but uses the build context's file system interface, if any.
-func IsAbsPath(ctxt *build.Context, path string) bool {
-	if ctxt.IsAbsPath != nil {
-		return ctxt.IsAbsPath(path)
-	}
-	return filepath.IsAbs(path)
-}
-
-// JoinPath behaves like filepath.Join,
-// but uses the build context's file system interface, if any.
-func JoinPath(ctxt *build.Context, path ...string) string {
-	if ctxt.JoinPath != nil {
-		return ctxt.JoinPath(path...)
-	}
-	return filepath.Join(path...)
-}
-
-// IsDir behaves like os.Stat plus IsDir,
-// but uses the build context's file system interface, if any.
-func IsDir(ctxt *build.Context, path string) bool {
-	if ctxt.IsDir != nil {
-		return ctxt.IsDir(path)
-	}
-	fi, err := os.Stat(path)
-	return err == nil && fi.IsDir()
-}
-
-// ReadDir behaves like ioutil.ReadDir,
-// but uses the build context's file system interface, if any.
-func ReadDir(ctxt *build.Context, path string) ([]os.FileInfo, error) {
-	if ctxt.ReadDir != nil {
-		return ctxt.ReadDir(path)
-	}
-	return ioutil.ReadDir(path)
-}
-
-// SplitPathList behaves like filepath.SplitList,
-// but uses the build context's file system interface, if any.
-func SplitPathList(ctxt *build.Context, s string) []string {
-	if ctxt.SplitPathList != nil {
-		return ctxt.SplitPathList(s)
-	}
-	return filepath.SplitList(s)
-}
-
-// sameFile returns true if x and y have the same basename and denote
-// the same file.
-//
-func sameFile(x, y string) bool {
-	if path.Clean(x) == path.Clean(y) {
-		return true
-	}
-	if filepath.Base(x) == filepath.Base(y) { // (optimisation)
-		if xi, err := os.Stat(x); err == nil {
-			if yi, err := os.Stat(y); err == nil {
-				return os.SameFile(xi, yi)
-			}
-		}
-	}
-	return false
-}
diff --git a/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go b/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go
deleted file mode 100644
index f8363d8faa..0000000000
--- a/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go
+++ /dev/null
@@ -1,109 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package gcexportdata provides functions for locating, reading, and
-// writing export data files containing type information produced by the
-// gc compiler.  This package supports go1.7 export data format and all
-// later versions.
-//
-// Although it might seem convenient for this package to live alongside
-// go/types in the standard library, this would cause version skew
-// problems for developer tools that use it, since they must be able to
-// consume the outputs of the gc compiler both before and after a Go
-// update such as from Go 1.7 to Go 1.8.  Because this package lives in
-// golang.org/x/tools, sites can update their version of this repo some
-// time before the Go 1.8 release and rebuild and redeploy their
-// developer tools, which will then be able to consume both Go 1.7 and
-// Go 1.8 export data files, so they will work before and after the
-// Go update. (See discussion at https://golang.org/issue/15651.)
-//
-package gcexportdata // import "golang.org/x/tools/go/gcexportdata"
-
-import (
-	"bufio"
-	"bytes"
-	"fmt"
-	"go/token"
-	"go/types"
-	"io"
-	"io/ioutil"
-
-	"golang.org/x/tools/go/internal/gcimporter"
-)
-
-// Find returns the name of an object (.o) or archive (.a) file
-// containing type information for the specified import path,
-// using the workspace layout conventions of go/build.
-// If no file was found, an empty filename is returned.
-//
-// A relative srcDir is interpreted relative to the current working directory.
-//
-// Find also returns the package's resolved (canonical) import path,
-// reflecting the effects of srcDir and vendoring on importPath.
-func Find(importPath, srcDir string) (filename, path string) {
-	return gcimporter.FindPkg(importPath, srcDir)
-}
-
-// NewReader returns a reader for the export data section of an object
-// (.o) or archive (.a) file read from r.  The new reader may provide
-// additional trailing data beyond the end of the export data.
-func NewReader(r io.Reader) (io.Reader, error) {
-	buf := bufio.NewReader(r)
-	_, err := gcimporter.FindExportData(buf)
-	// If we ever switch to a zip-like archive format with the ToC
-	// at the end, we can return the correct portion of export data,
-	// but for now we must return the entire rest of the file.
-	return buf, err
-}
-
-// Read reads export data from in, decodes it, and returns type
-// information for the package.
-// The package name is specified by path.
-// File position information is added to fset.
-//
-// Read may inspect and add to the imports map to ensure that references
-// within the export data to other packages are consistent.  The caller
-// must ensure that imports[path] does not exist, or exists but is
-// incomplete (see types.Package.Complete), and Read inserts the
-// resulting package into this map entry.
-//
-// On return, the state of the reader is undefined.
-func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package, path string) (*types.Package, error) {
-	data, err := ioutil.ReadAll(in)
-	if err != nil {
-		return nil, fmt.Errorf("reading export data for %q: %v", path, err)
-	}
-
-	if bytes.HasPrefix(data, []byte("!<arch>")) {
-		return nil, fmt.Errorf("can't read export data for %q directly from an archive file (call gcexportdata.NewReader first to extract export data)", path)
-	}
-
-	// The App Engine Go runtime v1.6 uses the old export data format.
-	// TODO(adonovan): delete once v1.7 has been around for a while.
-	if bytes.HasPrefix(data, []byte("package ")) {
-		return gcimporter.ImportData(imports, path, path, bytes.NewReader(data))
-	}
-
-	// The indexed export format starts with an 'i'; the older
-	// binary export format starts with a 'c', 'd', or 'v'
-	// (from "version"). Select appropriate importer.
-	if len(data) > 0 && data[0] == 'i' {
-		_, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path)
-		return pkg, err
-	}
-
-	_, pkg, err := gcimporter.BImportData(fset, imports, data, path)
-	return pkg, err
-}
-
-// Write writes encoded type information for the specified package to out.
-// The FileSet provides file position information for named objects.
-func Write(out io.Writer, fset *token.FileSet, pkg *types.Package) error {
-	b, err := gcimporter.IExportData(fset, pkg)
-	if err != nil {
-		return err
-	}
-	_, err = out.Write(b)
-	return err
-}
diff --git a/vendor/golang.org/x/tools/go/gcexportdata/importer.go b/vendor/golang.org/x/tools/go/gcexportdata/importer.go
deleted file mode 100644
index efe221e7e1..0000000000
--- a/vendor/golang.org/x/tools/go/gcexportdata/importer.go
+++ /dev/null
@@ -1,73 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package gcexportdata
-
-import (
-	"fmt"
-	"go/token"
-	"go/types"
-	"os"
-)
-
-// NewImporter returns a new instance of the types.Importer interface
-// that reads type information from export data files written by gc.
-// The Importer also satisfies types.ImporterFrom.
-//
-// Export data files are located using "go build" workspace conventions
-// and the build.Default context.
-//
-// Use this importer instead of go/importer.For("gc", ...) to avoid the
-// version-skew problems described in the documentation of this package,
-// or to control the FileSet or access the imports map populated during
-// package loading.
-//
-func NewImporter(fset *token.FileSet, imports map[string]*types.Package) types.ImporterFrom {
-	return importer{fset, imports}
-}
-
-type importer struct {
-	fset    *token.FileSet
-	imports map[string]*types.Package
-}
-
-func (imp importer) Import(importPath string) (*types.Package, error) {
-	return imp.ImportFrom(importPath, "", 0)
-}
-
-func (imp importer) ImportFrom(importPath, srcDir string, mode types.ImportMode) (_ *types.Package, err error) {
-	filename, path := Find(importPath, srcDir)
-	if filename == "" {
-		if importPath == "unsafe" {
-			// Even for unsafe, call Find first in case
-			// the package was vendored.
-			return types.Unsafe, nil
-		}
-		return nil, fmt.Errorf("can't find import: %s", importPath)
-	}
-
-	if pkg, ok := imp.imports[path]; ok && pkg.Complete() {
-		return pkg, nil // cache hit
-	}
-
-	// open file
-	f, err := os.Open(filename)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		f.Close()
-		if err != nil {
-			// add file name to error
-			err = fmt.Errorf("reading export data: %s: %v", filename, err)
-		}
-	}()
-
-	r, err := NewReader(f)
-	if err != nil {
-		return nil, err
-	}
-
-	return Read(r, imp.fset, imp.imports, path)
-}
diff --git a/vendor/golang.org/x/tools/go/internal/cgo/cgo.go b/vendor/golang.org/x/tools/go/internal/cgo/cgo.go
deleted file mode 100644
index 9772504c97..0000000000
--- a/vendor/golang.org/x/tools/go/internal/cgo/cgo.go
+++ /dev/null
@@ -1,220 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package cgo handles cgo preprocessing of files containing `import "C"`.
-//
-// DESIGN
-//
-// The approach taken is to run the cgo processor on the package's
-// CgoFiles and parse the output, faking the filenames of the
-// resulting ASTs so that the synthetic file containing the C types is
-// called "C" (e.g. "~/go/src/net/C") and the preprocessed files
-// have their original names (e.g. "~/go/src/net/cgo_unix.go"),
-// not the names of the actual temporary files.
-//
-// The advantage of this approach is its fidelity to 'go build'.  The
-// downside is that the token.Position.Offset for each AST node is
-// incorrect, being an offset within the temporary file.  Line numbers
-// should still be correct because of the //line comments.
-//
-// The logic of this file is mostly plundered from the 'go build'
-// tool, which also invokes the cgo preprocessor.
-//
-//
-// REJECTED ALTERNATIVE
-//
-// An alternative approach that we explored is to extend go/types'
-// Importer mechanism to provide the identity of the importing package
-// so that each time `import "C"` appears it resolves to a different
-// synthetic package containing just the objects needed in that case.
-// The loader would invoke cgo but parse only the cgo_types.go file
-// defining the package-level objects, discarding the other files
-// resulting from preprocessing.
-//
-// The benefit of this approach would have been that source-level
-// syntax information would correspond exactly to the original cgo
-// file, with no preprocessing involved, making source tools like
-// godoc, guru, and eg happy.  However, the approach was rejected
-// due to the additional complexity it would impose on go/types.  (It
-// made for a beautiful demo, though.)
-//
-// cgo files, despite their *.go extension, are not legal Go source
-// files per the specification since they may refer to unexported
-// members of package "C" such as C.int.  Also, a function such as
-// C.getpwent has in effect two types, one matching its C type and one
-// which additionally returns (errno C.int).  The cgo preprocessor
-// uses name mangling to distinguish these two functions in the
-// processed code, but go/types would need to duplicate this logic in
-// its handling of function calls, analogous to the treatment of map
-// lookups in which y=m[k] and y,ok=m[k] are both legal.
-
-package cgo
-
-import (
-	"fmt"
-	"go/ast"
-	"go/build"
-	"go/parser"
-	"go/token"
-	exec "golang.org/x/sys/execabs"
-	"io/ioutil"
-	"log"
-	"os"
-	"path/filepath"
-	"regexp"
-	"strings"
-)
-
-// ProcessFiles invokes the cgo preprocessor on bp.CgoFiles, parses
-// the output and returns the resulting ASTs.
-//
-func ProcessFiles(bp *build.Package, fset *token.FileSet, DisplayPath func(path string) string, mode parser.Mode) ([]*ast.File, error) {
-	tmpdir, err := ioutil.TempDir("", strings.Replace(bp.ImportPath, "/", "_", -1)+"_C")
-	if err != nil {
-		return nil, err
-	}
-	defer os.RemoveAll(tmpdir)
-
-	pkgdir := bp.Dir
-	if DisplayPath != nil {
-		pkgdir = DisplayPath(pkgdir)
-	}
-
-	cgoFiles, cgoDisplayFiles, err := Run(bp, pkgdir, tmpdir, false)
-	if err != nil {
-		return nil, err
-	}
-	var files []*ast.File
-	for i := range cgoFiles {
-		rd, err := os.Open(cgoFiles[i])
-		if err != nil {
-			return nil, err
-		}
-		display := filepath.Join(bp.Dir, cgoDisplayFiles[i])
-		f, err := parser.ParseFile(fset, display, rd, mode)
-		rd.Close()
-		if err != nil {
-			return nil, err
-		}
-		files = append(files, f)
-	}
-	return files, nil
-}
-
-var cgoRe = regexp.MustCompile(`[/\\:]`)
-
-// Run invokes the cgo preprocessor on bp.CgoFiles and returns two
-// lists of files: the resulting processed files (in temporary
-// directory tmpdir) and the corresponding names of the unprocessed files.
-//
-// Run is adapted from (*builder).cgo in
-// $GOROOT/src/cmd/go/build.go, but these features are unsupported:
-// Objective C, CGOPKGPATH, CGO_FLAGS.
-//
-// If useabs is set to true, absolute paths of the bp.CgoFiles will be passed in
-// to the cgo preprocessor. This in turn will set the // line comments
-// referring to those files to use absolute paths. This is needed for
-// go/packages using the legacy go list support so it is able to find
-// the original files.
-func Run(bp *build.Package, pkgdir, tmpdir string, useabs bool) (files, displayFiles []string, err error) {
-	cgoCPPFLAGS, _, _, _ := cflags(bp, true)
-	_, cgoexeCFLAGS, _, _ := cflags(bp, false)
-
-	if len(bp.CgoPkgConfig) > 0 {
-		pcCFLAGS, err := pkgConfigFlags(bp)
-		if err != nil {
-			return nil, nil, err
-		}
-		cgoCPPFLAGS = append(cgoCPPFLAGS, pcCFLAGS...)
-	}
-
-	// Allows including _cgo_export.h from .[ch] files in the package.
-	cgoCPPFLAGS = append(cgoCPPFLAGS, "-I", tmpdir)
-
-	// _cgo_gotypes.go (displayed "C") contains the type definitions.
-	files = append(files, filepath.Join(tmpdir, "_cgo_gotypes.go"))
-	displayFiles = append(displayFiles, "C")
-	for _, fn := range bp.CgoFiles {
-		// "foo.cgo1.go" (displayed "foo.go") is the processed Go source.
-		f := cgoRe.ReplaceAllString(fn[:len(fn)-len("go")], "_")
-		files = append(files, filepath.Join(tmpdir, f+"cgo1.go"))
-		displayFiles = append(displayFiles, fn)
-	}
-
-	var cgoflags []string
-	if bp.Goroot && bp.ImportPath == "runtime/cgo" {
-		cgoflags = append(cgoflags, "-import_runtime_cgo=false")
-	}
-	if bp.Goroot && bp.ImportPath == "runtime/race" || bp.ImportPath == "runtime/cgo" {
-		cgoflags = append(cgoflags, "-import_syscall=false")
-	}
-
-	var cgoFiles []string = bp.CgoFiles
-	if useabs {
-		cgoFiles = make([]string, len(bp.CgoFiles))
-		for i := range cgoFiles {
-			cgoFiles[i] = filepath.Join(pkgdir, bp.CgoFiles[i])
-		}
-	}
-
-	args := stringList(
-		"go", "tool", "cgo", "-objdir", tmpdir, cgoflags, "--",
-		cgoCPPFLAGS, cgoexeCFLAGS, cgoFiles,
-	)
-	if false {
-		log.Printf("Running cgo for package %q: %s (dir=%s)", bp.ImportPath, args, pkgdir)
-	}
-	cmd := exec.Command(args[0], args[1:]...)
-	cmd.Dir = pkgdir
-	cmd.Stdout = os.Stderr
-	cmd.Stderr = os.Stderr
-	if err := cmd.Run(); err != nil {
-		return nil, nil, fmt.Errorf("cgo failed: %s: %s", args, err)
-	}
-
-	return files, displayFiles, nil
-}
-
-// -- unmodified from 'go build' ---------------------------------------
-
-// Return the flags to use when invoking the C or C++ compilers, or cgo.
-func cflags(p *build.Package, def bool) (cppflags, cflags, cxxflags, ldflags []string) {
-	var defaults string
-	if def {
-		defaults = "-g -O2"
-	}
-
-	cppflags = stringList(envList("CGO_CPPFLAGS", ""), p.CgoCPPFLAGS)
-	cflags = stringList(envList("CGO_CFLAGS", defaults), p.CgoCFLAGS)
-	cxxflags = stringList(envList("CGO_CXXFLAGS", defaults), p.CgoCXXFLAGS)
-	ldflags = stringList(envList("CGO_LDFLAGS", defaults), p.CgoLDFLAGS)
-	return
-}
-
-// envList returns the value of the given environment variable broken
-// into fields, using the default value when the variable is empty.
-func envList(key, def string) []string {
-	v := os.Getenv(key)
-	if v == "" {
-		v = def
-	}
-	return strings.Fields(v)
-}
-
-// stringList's arguments should be a sequence of string or []string values.
-// stringList flattens them into a single []string.
-func stringList(args ...interface{}) []string {
-	var x []string
-	for _, arg := range args {
-		switch arg := arg.(type) {
-		case []string:
-			x = append(x, arg...)
-		case string:
-			x = append(x, arg)
-		default:
-			panic("stringList: invalid argument")
-		}
-	}
-	return x
-}
diff --git a/vendor/golang.org/x/tools/go/internal/cgo/cgo_pkgconfig.go b/vendor/golang.org/x/tools/go/internal/cgo/cgo_pkgconfig.go
deleted file mode 100644
index 7d94bbc1e5..0000000000
--- a/vendor/golang.org/x/tools/go/internal/cgo/cgo_pkgconfig.go
+++ /dev/null
@@ -1,39 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package cgo
-
-import (
-	"errors"
-	"fmt"
-	"go/build"
-	exec "golang.org/x/sys/execabs"
-	"strings"
-)
-
-// pkgConfig runs pkg-config with the specified arguments and returns the flags it prints.
-func pkgConfig(mode string, pkgs []string) (flags []string, err error) {
-	cmd := exec.Command("pkg-config", append([]string{mode}, pkgs...)...)
-	out, err := cmd.CombinedOutput()
-	if err != nil {
-		s := fmt.Sprintf("%s failed: %v", strings.Join(cmd.Args, " "), err)
-		if len(out) > 0 {
-			s = fmt.Sprintf("%s: %s", s, out)
-		}
-		return nil, errors.New(s)
-	}
-	if len(out) > 0 {
-		flags = strings.Fields(string(out))
-	}
-	return
-}
-
-// pkgConfigFlags calls pkg-config if needed and returns the cflags
-// needed to build the package.
-func pkgConfigFlags(p *build.Package) (cflags []string, err error) {
-	if len(p.CgoPkgConfig) == 0 {
-		return nil, nil
-	}
-	return pkgConfig("--cflags", p.CgoPkgConfig)
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go
deleted file mode 100644
index a807d0aaa2..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go
+++ /dev/null
@@ -1,852 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Binary package export.
-// This file was derived from $GOROOT/src/cmd/compile/internal/gc/bexport.go;
-// see that file for specification of the format.
-
-package gcimporter
-
-import (
-	"bytes"
-	"encoding/binary"
-	"fmt"
-	"go/ast"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"math"
-	"math/big"
-	"sort"
-	"strings"
-)
-
-// If debugFormat is set, each integer and string value is preceded by a marker
-// and position information in the encoding. This mechanism permits an importer
-// to recognize immediately when it is out of sync. The importer recognizes this
-// mode automatically (i.e., it can import export data produced with debugging
-// support even if debugFormat is not set at the time of import). This mode will
-// lead to massively larger export data (by a factor of 2 to 3) and should only
-// be enabled during development and debugging.
-//
-// NOTE: This flag is the first flag to enable if importing dies because of
-// (suspected) format errors, and whenever a change is made to the format.
-const debugFormat = false // default: false
-
-// If trace is set, debugging output is printed to std out.
-const trace = false // default: false
-
-// Current export format version. Increase with each format change.
-// Note: The latest binary (non-indexed) export format is at version 6.
-//       This exporter is still at level 4, but it doesn't matter since
-//       the binary importer can handle older versions just fine.
-// 6: package height (CL 105038) -- NOT IMPLEMENTED HERE
-// 5: improved position encoding efficiency (issue 20080, CL 41619) -- NOT IMPLEMEMTED HERE
-// 4: type name objects support type aliases, uses aliasTag
-// 3: Go1.8 encoding (same as version 2, aliasTag defined but never used)
-// 2: removed unused bool in ODCL export (compiler only)
-// 1: header format change (more regular), export package for _ struct fields
-// 0: Go1.7 encoding
-const exportVersion = 4
-
-// trackAllTypes enables cycle tracking for all types, not just named
-// types. The existing compiler invariants assume that unnamed types
-// that are not completely set up are not used, or else there are spurious
-// errors.
-// If disabled, only named types are tracked, possibly leading to slightly
-// less efficient encoding in rare cases. It also prevents the export of
-// some corner-case type declarations (but those are not handled correctly
-// with with the textual export format either).
-// TODO(gri) enable and remove once issues caused by it are fixed
-const trackAllTypes = false
-
-type exporter struct {
-	fset *token.FileSet
-	out  bytes.Buffer
-
-	// object -> index maps, indexed in order of serialization
-	strIndex map[string]int
-	pkgIndex map[*types.Package]int
-	typIndex map[types.Type]int
-
-	// position encoding
-	posInfoFormat bool
-	prevFile      string
-	prevLine      int
-
-	// debugging support
-	written int // bytes written
-	indent  int // for trace
-}
-
-// internalError represents an error generated inside this package.
-type internalError string
-
-func (e internalError) Error() string { return "gcimporter: " + string(e) }
-
-func internalErrorf(format string, args ...interface{}) error {
-	return internalError(fmt.Sprintf(format, args...))
-}
-
-// BExportData returns binary export data for pkg.
-// If no file set is provided, position info will be missing.
-func BExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
-	defer func() {
-		if e := recover(); e != nil {
-			if ierr, ok := e.(internalError); ok {
-				err = ierr
-				return
-			}
-			// Not an internal error; panic again.
-			panic(e)
-		}
-	}()
-
-	p := exporter{
-		fset:          fset,
-		strIndex:      map[string]int{"": 0}, // empty string is mapped to 0
-		pkgIndex:      make(map[*types.Package]int),
-		typIndex:      make(map[types.Type]int),
-		posInfoFormat: true, // TODO(gri) might become a flag, eventually
-	}
-
-	// write version info
-	// The version string must start with "version %d" where %d is the version
-	// number. Additional debugging information may follow after a blank; that
-	// text is ignored by the importer.
-	p.rawStringln(fmt.Sprintf("version %d", exportVersion))
-	var debug string
-	if debugFormat {
-		debug = "debug"
-	}
-	p.rawStringln(debug) // cannot use p.bool since it's affected by debugFormat; also want to see this clearly
-	p.bool(trackAllTypes)
-	p.bool(p.posInfoFormat)
-
-	// --- generic export data ---
-
-	// populate type map with predeclared "known" types
-	for index, typ := range predeclared() {
-		p.typIndex[typ] = index
-	}
-	if len(p.typIndex) != len(predeclared()) {
-		return nil, internalError("duplicate entries in type map?")
-	}
-
-	// write package data
-	p.pkg(pkg, true)
-	if trace {
-		p.tracef("\n")
-	}
-
-	// write objects
-	objcount := 0
-	scope := pkg.Scope()
-	for _, name := range scope.Names() {
-		if !ast.IsExported(name) {
-			continue
-		}
-		if trace {
-			p.tracef("\n")
-		}
-		p.obj(scope.Lookup(name))
-		objcount++
-	}
-
-	// indicate end of list
-	if trace {
-		p.tracef("\n")
-	}
-	p.tag(endTag)
-
-	// for self-verification only (redundant)
-	p.int(objcount)
-
-	if trace {
-		p.tracef("\n")
-	}
-
-	// --- end of export data ---
-
-	return p.out.Bytes(), nil
-}
-
-func (p *exporter) pkg(pkg *types.Package, emptypath bool) {
-	if pkg == nil {
-		panic(internalError("unexpected nil pkg"))
-	}
-
-	// if we saw the package before, write its index (>= 0)
-	if i, ok := p.pkgIndex[pkg]; ok {
-		p.index('P', i)
-		return
-	}
-
-	// otherwise, remember the package, write the package tag (< 0) and package data
-	if trace {
-		p.tracef("P%d = { ", len(p.pkgIndex))
-		defer p.tracef("} ")
-	}
-	p.pkgIndex[pkg] = len(p.pkgIndex)
-
-	p.tag(packageTag)
-	p.string(pkg.Name())
-	if emptypath {
-		p.string("")
-	} else {
-		p.string(pkg.Path())
-	}
-}
-
-func (p *exporter) obj(obj types.Object) {
-	switch obj := obj.(type) {
-	case *types.Const:
-		p.tag(constTag)
-		p.pos(obj)
-		p.qualifiedName(obj)
-		p.typ(obj.Type())
-		p.value(obj.Val())
-
-	case *types.TypeName:
-		if obj.IsAlias() {
-			p.tag(aliasTag)
-			p.pos(obj)
-			p.qualifiedName(obj)
-		} else {
-			p.tag(typeTag)
-		}
-		p.typ(obj.Type())
-
-	case *types.Var:
-		p.tag(varTag)
-		p.pos(obj)
-		p.qualifiedName(obj)
-		p.typ(obj.Type())
-
-	case *types.Func:
-		p.tag(funcTag)
-		p.pos(obj)
-		p.qualifiedName(obj)
-		sig := obj.Type().(*types.Signature)
-		p.paramList(sig.Params(), sig.Variadic())
-		p.paramList(sig.Results(), false)
-
-	default:
-		panic(internalErrorf("unexpected object %v (%T)", obj, obj))
-	}
-}
-
-func (p *exporter) pos(obj types.Object) {
-	if !p.posInfoFormat {
-		return
-	}
-
-	file, line := p.fileLine(obj)
-	if file == p.prevFile {
-		// common case: write line delta
-		// delta == 0 means different file or no line change
-		delta := line - p.prevLine
-		p.int(delta)
-		if delta == 0 {
-			p.int(-1) // -1 means no file change
-		}
-	} else {
-		// different file
-		p.int(0)
-		// Encode filename as length of common prefix with previous
-		// filename, followed by (possibly empty) suffix. Filenames
-		// frequently share path prefixes, so this can save a lot
-		// of space and make export data size less dependent on file
-		// path length. The suffix is unlikely to be empty because
-		// file names tend to end in ".go".
-		n := commonPrefixLen(p.prevFile, file)
-		p.int(n)           // n >= 0
-		p.string(file[n:]) // write suffix only
-		p.prevFile = file
-		p.int(line)
-	}
-	p.prevLine = line
-}
-
-func (p *exporter) fileLine(obj types.Object) (file string, line int) {
-	if p.fset != nil {
-		pos := p.fset.Position(obj.Pos())
-		file = pos.Filename
-		line = pos.Line
-	}
-	return
-}
-
-func commonPrefixLen(a, b string) int {
-	if len(a) > len(b) {
-		a, b = b, a
-	}
-	// len(a) <= len(b)
-	i := 0
-	for i < len(a) && a[i] == b[i] {
-		i++
-	}
-	return i
-}
-
-func (p *exporter) qualifiedName(obj types.Object) {
-	p.string(obj.Name())
-	p.pkg(obj.Pkg(), false)
-}
-
-func (p *exporter) typ(t types.Type) {
-	if t == nil {
-		panic(internalError("nil type"))
-	}
-
-	// Possible optimization: Anonymous pointer types *T where
-	// T is a named type are common. We could canonicalize all
-	// such types *T to a single type PT = *T. This would lead
-	// to at most one *T entry in typIndex, and all future *T's
-	// would be encoded as the respective index directly. Would
-	// save 1 byte (pointerTag) per *T and reduce the typIndex
-	// size (at the cost of a canonicalization map). We can do
-	// this later, without encoding format change.
-
-	// if we saw the type before, write its index (>= 0)
-	if i, ok := p.typIndex[t]; ok {
-		p.index('T', i)
-		return
-	}
-
-	// otherwise, remember the type, write the type tag (< 0) and type data
-	if trackAllTypes {
-		if trace {
-			p.tracef("T%d = {>\n", len(p.typIndex))
-			defer p.tracef("<\n} ")
-		}
-		p.typIndex[t] = len(p.typIndex)
-	}
-
-	switch t := t.(type) {
-	case *types.Named:
-		if !trackAllTypes {
-			// if we don't track all types, track named types now
-			p.typIndex[t] = len(p.typIndex)
-		}
-
-		p.tag(namedTag)
-		p.pos(t.Obj())
-		p.qualifiedName(t.Obj())
-		p.typ(t.Underlying())
-		if !types.IsInterface(t) {
-			p.assocMethods(t)
-		}
-
-	case *types.Array:
-		p.tag(arrayTag)
-		p.int64(t.Len())
-		p.typ(t.Elem())
-
-	case *types.Slice:
-		p.tag(sliceTag)
-		p.typ(t.Elem())
-
-	case *dddSlice:
-		p.tag(dddTag)
-		p.typ(t.elem)
-
-	case *types.Struct:
-		p.tag(structTag)
-		p.fieldList(t)
-
-	case *types.Pointer:
-		p.tag(pointerTag)
-		p.typ(t.Elem())
-
-	case *types.Signature:
-		p.tag(signatureTag)
-		p.paramList(t.Params(), t.Variadic())
-		p.paramList(t.Results(), false)
-
-	case *types.Interface:
-		p.tag(interfaceTag)
-		p.iface(t)
-
-	case *types.Map:
-		p.tag(mapTag)
-		p.typ(t.Key())
-		p.typ(t.Elem())
-
-	case *types.Chan:
-		p.tag(chanTag)
-		p.int(int(3 - t.Dir())) // hack
-		p.typ(t.Elem())
-
-	default:
-		panic(internalErrorf("unexpected type %T: %s", t, t))
-	}
-}
-
-func (p *exporter) assocMethods(named *types.Named) {
-	// Sort methods (for determinism).
-	var methods []*types.Func
-	for i := 0; i < named.NumMethods(); i++ {
-		methods = append(methods, named.Method(i))
-	}
-	sort.Sort(methodsByName(methods))
-
-	p.int(len(methods))
-
-	if trace && methods != nil {
-		p.tracef("associated methods {>\n")
-	}
-
-	for i, m := range methods {
-		if trace && i > 0 {
-			p.tracef("\n")
-		}
-
-		p.pos(m)
-		name := m.Name()
-		p.string(name)
-		if !exported(name) {
-			p.pkg(m.Pkg(), false)
-		}
-
-		sig := m.Type().(*types.Signature)
-		p.paramList(types.NewTuple(sig.Recv()), false)
-		p.paramList(sig.Params(), sig.Variadic())
-		p.paramList(sig.Results(), false)
-		p.int(0) // dummy value for go:nointerface pragma - ignored by importer
-	}
-
-	if trace && methods != nil {
-		p.tracef("<\n} ")
-	}
-}
-
-type methodsByName []*types.Func
-
-func (x methodsByName) Len() int           { return len(x) }
-func (x methodsByName) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x methodsByName) Less(i, j int) bool { return x[i].Name() < x[j].Name() }
-
-func (p *exporter) fieldList(t *types.Struct) {
-	if trace && t.NumFields() > 0 {
-		p.tracef("fields {>\n")
-		defer p.tracef("<\n} ")
-	}
-
-	p.int(t.NumFields())
-	for i := 0; i < t.NumFields(); i++ {
-		if trace && i > 0 {
-			p.tracef("\n")
-		}
-		p.field(t.Field(i))
-		p.string(t.Tag(i))
-	}
-}
-
-func (p *exporter) field(f *types.Var) {
-	if !f.IsField() {
-		panic(internalError("field expected"))
-	}
-
-	p.pos(f)
-	p.fieldName(f)
-	p.typ(f.Type())
-}
-
-func (p *exporter) iface(t *types.Interface) {
-	// TODO(gri): enable importer to load embedded interfaces,
-	// then emit Embeddeds and ExplicitMethods separately here.
-	p.int(0)
-
-	n := t.NumMethods()
-	if trace && n > 0 {
-		p.tracef("methods {>\n")
-		defer p.tracef("<\n} ")
-	}
-	p.int(n)
-	for i := 0; i < n; i++ {
-		if trace && i > 0 {
-			p.tracef("\n")
-		}
-		p.method(t.Method(i))
-	}
-}
-
-func (p *exporter) method(m *types.Func) {
-	sig := m.Type().(*types.Signature)
-	if sig.Recv() == nil {
-		panic(internalError("method expected"))
-	}
-
-	p.pos(m)
-	p.string(m.Name())
-	if m.Name() != "_" && !ast.IsExported(m.Name()) {
-		p.pkg(m.Pkg(), false)
-	}
-
-	// interface method; no need to encode receiver.
-	p.paramList(sig.Params(), sig.Variadic())
-	p.paramList(sig.Results(), false)
-}
-
-func (p *exporter) fieldName(f *types.Var) {
-	name := f.Name()
-
-	if f.Anonymous() {
-		// anonymous field - we distinguish between 3 cases:
-		// 1) field name matches base type name and is exported
-		// 2) field name matches base type name and is not exported
-		// 3) field name doesn't match base type name (alias name)
-		bname := basetypeName(f.Type())
-		if name == bname {
-			if ast.IsExported(name) {
-				name = "" // 1) we don't need to know the field name or package
-			} else {
-				name = "?" // 2) use unexported name "?" to force package export
-			}
-		} else {
-			// 3) indicate alias and export name as is
-			// (this requires an extra "@" but this is a rare case)
-			p.string("@")
-		}
-	}
-
-	p.string(name)
-	if name != "" && !ast.IsExported(name) {
-		p.pkg(f.Pkg(), false)
-	}
-}
-
-func basetypeName(typ types.Type) string {
-	switch typ := deref(typ).(type) {
-	case *types.Basic:
-		return typ.Name()
-	case *types.Named:
-		return typ.Obj().Name()
-	default:
-		return "" // unnamed type
-	}
-}
-
-func (p *exporter) paramList(params *types.Tuple, variadic bool) {
-	// use negative length to indicate unnamed parameters
-	// (look at the first parameter only since either all
-	// names are present or all are absent)
-	n := params.Len()
-	if n > 0 && params.At(0).Name() == "" {
-		n = -n
-	}
-	p.int(n)
-	for i := 0; i < params.Len(); i++ {
-		q := params.At(i)
-		t := q.Type()
-		if variadic && i == params.Len()-1 {
-			t = &dddSlice{t.(*types.Slice).Elem()}
-		}
-		p.typ(t)
-		if n > 0 {
-			name := q.Name()
-			p.string(name)
-			if name != "_" {
-				p.pkg(q.Pkg(), false)
-			}
-		}
-		p.string("") // no compiler-specific info
-	}
-}
-
-func (p *exporter) value(x constant.Value) {
-	if trace {
-		p.tracef("= ")
-	}
-
-	switch x.Kind() {
-	case constant.Bool:
-		tag := falseTag
-		if constant.BoolVal(x) {
-			tag = trueTag
-		}
-		p.tag(tag)
-
-	case constant.Int:
-		if v, exact := constant.Int64Val(x); exact {
-			// common case: x fits into an int64 - use compact encoding
-			p.tag(int64Tag)
-			p.int64(v)
-			return
-		}
-		// uncommon case: large x - use float encoding
-		// (powers of 2 will be encoded efficiently with exponent)
-		p.tag(floatTag)
-		p.float(constant.ToFloat(x))
-
-	case constant.Float:
-		p.tag(floatTag)
-		p.float(x)
-
-	case constant.Complex:
-		p.tag(complexTag)
-		p.float(constant.Real(x))
-		p.float(constant.Imag(x))
-
-	case constant.String:
-		p.tag(stringTag)
-		p.string(constant.StringVal(x))
-
-	case constant.Unknown:
-		// package contains type errors
-		p.tag(unknownTag)
-
-	default:
-		panic(internalErrorf("unexpected value %v (%T)", x, x))
-	}
-}
-
-func (p *exporter) float(x constant.Value) {
-	if x.Kind() != constant.Float {
-		panic(internalErrorf("unexpected constant %v, want float", x))
-	}
-	// extract sign (there is no -0)
-	sign := constant.Sign(x)
-	if sign == 0 {
-		// x == 0
-		p.int(0)
-		return
-	}
-	// x != 0
-
-	var f big.Float
-	if v, exact := constant.Float64Val(x); exact {
-		// float64
-		f.SetFloat64(v)
-	} else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
-		// TODO(gri): add big.Rat accessor to constant.Value.
-		r := valueToRat(num)
-		f.SetRat(r.Quo(r, valueToRat(denom)))
-	} else {
-		// Value too large to represent as a fraction => inaccessible.
-		// TODO(gri): add big.Float accessor to constant.Value.
-		f.SetFloat64(math.MaxFloat64) // FIXME
-	}
-
-	// extract exponent such that 0.5 <= m < 1.0
-	var m big.Float
-	exp := f.MantExp(&m)
-
-	// extract mantissa as *big.Int
-	// - set exponent large enough so mant satisfies mant.IsInt()
-	// - get *big.Int from mant
-	m.SetMantExp(&m, int(m.MinPrec()))
-	mant, acc := m.Int(nil)
-	if acc != big.Exact {
-		panic(internalError("internal error"))
-	}
-
-	p.int(sign)
-	p.int(exp)
-	p.string(string(mant.Bytes()))
-}
-
-func valueToRat(x constant.Value) *big.Rat {
-	// Convert little-endian to big-endian.
-	// I can't believe this is necessary.
-	bytes := constant.Bytes(x)
-	for i := 0; i < len(bytes)/2; i++ {
-		bytes[i], bytes[len(bytes)-1-i] = bytes[len(bytes)-1-i], bytes[i]
-	}
-	return new(big.Rat).SetInt(new(big.Int).SetBytes(bytes))
-}
-
-func (p *exporter) bool(b bool) bool {
-	if trace {
-		p.tracef("[")
-		defer p.tracef("= %v] ", b)
-	}
-
-	x := 0
-	if b {
-		x = 1
-	}
-	p.int(x)
-	return b
-}
-
-// ----------------------------------------------------------------------------
-// Low-level encoders
-
-func (p *exporter) index(marker byte, index int) {
-	if index < 0 {
-		panic(internalError("invalid index < 0"))
-	}
-	if debugFormat {
-		p.marker('t')
-	}
-	if trace {
-		p.tracef("%c%d ", marker, index)
-	}
-	p.rawInt64(int64(index))
-}
-
-func (p *exporter) tag(tag int) {
-	if tag >= 0 {
-		panic(internalError("invalid tag >= 0"))
-	}
-	if debugFormat {
-		p.marker('t')
-	}
-	if trace {
-		p.tracef("%s ", tagString[-tag])
-	}
-	p.rawInt64(int64(tag))
-}
-
-func (p *exporter) int(x int) {
-	p.int64(int64(x))
-}
-
-func (p *exporter) int64(x int64) {
-	if debugFormat {
-		p.marker('i')
-	}
-	if trace {
-		p.tracef("%d ", x)
-	}
-	p.rawInt64(x)
-}
-
-func (p *exporter) string(s string) {
-	if debugFormat {
-		p.marker('s')
-	}
-	if trace {
-		p.tracef("%q ", s)
-	}
-	// if we saw the string before, write its index (>= 0)
-	// (the empty string is mapped to 0)
-	if i, ok := p.strIndex[s]; ok {
-		p.rawInt64(int64(i))
-		return
-	}
-	// otherwise, remember string and write its negative length and bytes
-	p.strIndex[s] = len(p.strIndex)
-	p.rawInt64(-int64(len(s)))
-	for i := 0; i < len(s); i++ {
-		p.rawByte(s[i])
-	}
-}
-
-// marker emits a marker byte and position information which makes
-// it easy for a reader to detect if it is "out of sync". Used for
-// debugFormat format only.
-func (p *exporter) marker(m byte) {
-	p.rawByte(m)
-	// Enable this for help tracking down the location
-	// of an incorrect marker when running in debugFormat.
-	if false && trace {
-		p.tracef("#%d ", p.written)
-	}
-	p.rawInt64(int64(p.written))
-}
-
-// rawInt64 should only be used by low-level encoders.
-func (p *exporter) rawInt64(x int64) {
-	var tmp [binary.MaxVarintLen64]byte
-	n := binary.PutVarint(tmp[:], x)
-	for i := 0; i < n; i++ {
-		p.rawByte(tmp[i])
-	}
-}
-
-// rawStringln should only be used to emit the initial version string.
-func (p *exporter) rawStringln(s string) {
-	for i := 0; i < len(s); i++ {
-		p.rawByte(s[i])
-	}
-	p.rawByte('\n')
-}
-
-// rawByte is the bottleneck interface to write to p.out.
-// rawByte escapes b as follows (any encoding does that
-// hides '$'):
-//
-//	'$'  => '|' 'S'
-//	'|'  => '|' '|'
-//
-// Necessary so other tools can find the end of the
-// export data by searching for "$$".
-// rawByte should only be used by low-level encoders.
-func (p *exporter) rawByte(b byte) {
-	switch b {
-	case '$':
-		// write '$' as '|' 'S'
-		b = 'S'
-		fallthrough
-	case '|':
-		// write '|' as '|' '|'
-		p.out.WriteByte('|')
-		p.written++
-	}
-	p.out.WriteByte(b)
-	p.written++
-}
-
-// tracef is like fmt.Printf but it rewrites the format string
-// to take care of indentation.
-func (p *exporter) tracef(format string, args ...interface{}) {
-	if strings.ContainsAny(format, "<>\n") {
-		var buf bytes.Buffer
-		for i := 0; i < len(format); i++ {
-			// no need to deal with runes
-			ch := format[i]
-			switch ch {
-			case '>':
-				p.indent++
-				continue
-			case '<':
-				p.indent--
-				continue
-			}
-			buf.WriteByte(ch)
-			if ch == '\n' {
-				for j := p.indent; j > 0; j-- {
-					buf.WriteString(".  ")
-				}
-			}
-		}
-		format = buf.String()
-	}
-	fmt.Printf(format, args...)
-}
-
-// Debugging support.
-// (tagString is only used when tracing is enabled)
-var tagString = [...]string{
-	// Packages
-	-packageTag: "package",
-
-	// Types
-	-namedTag:     "named type",
-	-arrayTag:     "array",
-	-sliceTag:     "slice",
-	-dddTag:       "ddd",
-	-structTag:    "struct",
-	-pointerTag:   "pointer",
-	-signatureTag: "signature",
-	-interfaceTag: "interface",
-	-mapTag:       "map",
-	-chanTag:      "chan",
-
-	// Values
-	-falseTag:    "false",
-	-trueTag:     "true",
-	-int64Tag:    "int64",
-	-floatTag:    "float",
-	-fractionTag: "fraction",
-	-complexTag:  "complex",
-	-stringTag:   "string",
-	-unknownTag:  "unknown",
-
-	// Type aliases
-	-aliasTag: "alias",
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go
deleted file mode 100644
index e9f73d14a1..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go
+++ /dev/null
@@ -1,1039 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file is a copy of $GOROOT/src/go/internal/gcimporter/bimport.go.
-
-package gcimporter
-
-import (
-	"encoding/binary"
-	"fmt"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"sort"
-	"strconv"
-	"strings"
-	"sync"
-	"unicode"
-	"unicode/utf8"
-)
-
-type importer struct {
-	imports    map[string]*types.Package
-	data       []byte
-	importpath string
-	buf        []byte // for reading strings
-	version    int    // export format version
-
-	// object lists
-	strList       []string           // in order of appearance
-	pathList      []string           // in order of appearance
-	pkgList       []*types.Package   // in order of appearance
-	typList       []types.Type       // in order of appearance
-	interfaceList []*types.Interface // for delayed completion only
-	trackAllTypes bool
-
-	// position encoding
-	posInfoFormat bool
-	prevFile      string
-	prevLine      int
-	fake          fakeFileSet
-
-	// debugging support
-	debugFormat bool
-	read        int // bytes read
-}
-
-// BImportData imports a package from the serialized package data
-// and returns the number of bytes consumed and a reference to the package.
-// If the export data version is not recognized or the format is otherwise
-// compromised, an error is returned.
-func BImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (_ int, pkg *types.Package, err error) {
-	// catch panics and return them as errors
-	const currentVersion = 6
-	version := -1 // unknown version
-	defer func() {
-		if e := recover(); e != nil {
-			// Return a (possibly nil or incomplete) package unchanged (see #16088).
-			if version > currentVersion {
-				err = fmt.Errorf("cannot import %q (%v), export data is newer version - update tool", path, e)
-			} else {
-				err = fmt.Errorf("cannot import %q (%v), possibly version skew - reinstall package", path, e)
-			}
-		}
-	}()
-
-	p := importer{
-		imports:    imports,
-		data:       data,
-		importpath: path,
-		version:    version,
-		strList:    []string{""}, // empty string is mapped to 0
-		pathList:   []string{""}, // empty string is mapped to 0
-		fake: fakeFileSet{
-			fset:  fset,
-			files: make(map[string]*token.File),
-		},
-	}
-
-	// read version info
-	var versionstr string
-	if b := p.rawByte(); b == 'c' || b == 'd' {
-		// Go1.7 encoding; first byte encodes low-level
-		// encoding format (compact vs debug).
-		// For backward-compatibility only (avoid problems with
-		// old installed packages). Newly compiled packages use
-		// the extensible format string.
-		// TODO(gri) Remove this support eventually; after Go1.8.
-		if b == 'd' {
-			p.debugFormat = true
-		}
-		p.trackAllTypes = p.rawByte() == 'a'
-		p.posInfoFormat = p.int() != 0
-		versionstr = p.string()
-		if versionstr == "v1" {
-			version = 0
-		}
-	} else {
-		// Go1.8 extensible encoding
-		// read version string and extract version number (ignore anything after the version number)
-		versionstr = p.rawStringln(b)
-		if s := strings.SplitN(versionstr, " ", 3); len(s) >= 2 && s[0] == "version" {
-			if v, err := strconv.Atoi(s[1]); err == nil && v > 0 {
-				version = v
-			}
-		}
-	}
-	p.version = version
-
-	// read version specific flags - extend as necessary
-	switch p.version {
-	// case currentVersion:
-	// 	...
-	//	fallthrough
-	case currentVersion, 5, 4, 3, 2, 1:
-		p.debugFormat = p.rawStringln(p.rawByte()) == "debug"
-		p.trackAllTypes = p.int() != 0
-		p.posInfoFormat = p.int() != 0
-	case 0:
-		// Go1.7 encoding format - nothing to do here
-	default:
-		errorf("unknown bexport format version %d (%q)", p.version, versionstr)
-	}
-
-	// --- generic export data ---
-
-	// populate typList with predeclared "known" types
-	p.typList = append(p.typList, predeclared()...)
-
-	// read package data
-	pkg = p.pkg()
-
-	// read objects of phase 1 only (see cmd/compile/internal/gc/bexport.go)
-	objcount := 0
-	for {
-		tag := p.tagOrIndex()
-		if tag == endTag {
-			break
-		}
-		p.obj(tag)
-		objcount++
-	}
-
-	// self-verification
-	if count := p.int(); count != objcount {
-		errorf("got %d objects; want %d", objcount, count)
-	}
-
-	// ignore compiler-specific import data
-
-	// complete interfaces
-	// TODO(gri) re-investigate if we still need to do this in a delayed fashion
-	for _, typ := range p.interfaceList {
-		typ.Complete()
-	}
-
-	// record all referenced packages as imports
-	list := append(([]*types.Package)(nil), p.pkgList[1:]...)
-	sort.Sort(byPath(list))
-	pkg.SetImports(list)
-
-	// package was imported completely and without errors
-	pkg.MarkComplete()
-
-	return p.read, pkg, nil
-}
-
-func errorf(format string, args ...interface{}) {
-	panic(fmt.Sprintf(format, args...))
-}
-
-func (p *importer) pkg() *types.Package {
-	// if the package was seen before, i is its index (>= 0)
-	i := p.tagOrIndex()
-	if i >= 0 {
-		return p.pkgList[i]
-	}
-
-	// otherwise, i is the package tag (< 0)
-	if i != packageTag {
-		errorf("unexpected package tag %d version %d", i, p.version)
-	}
-
-	// read package data
-	name := p.string()
-	var path string
-	if p.version >= 5 {
-		path = p.path()
-	} else {
-		path = p.string()
-	}
-	if p.version >= 6 {
-		p.int() // package height; unused by go/types
-	}
-
-	// we should never see an empty package name
-	if name == "" {
-		errorf("empty package name in import")
-	}
-
-	// an empty path denotes the package we are currently importing;
-	// it must be the first package we see
-	if (path == "") != (len(p.pkgList) == 0) {
-		errorf("package path %q for pkg index %d", path, len(p.pkgList))
-	}
-
-	// if the package was imported before, use that one; otherwise create a new one
-	if path == "" {
-		path = p.importpath
-	}
-	pkg := p.imports[path]
-	if pkg == nil {
-		pkg = types.NewPackage(path, name)
-		p.imports[path] = pkg
-	} else if pkg.Name() != name {
-		errorf("conflicting names %s and %s for package %q", pkg.Name(), name, path)
-	}
-	p.pkgList = append(p.pkgList, pkg)
-
-	return pkg
-}
-
-// objTag returns the tag value for each object kind.
-func objTag(obj types.Object) int {
-	switch obj.(type) {
-	case *types.Const:
-		return constTag
-	case *types.TypeName:
-		return typeTag
-	case *types.Var:
-		return varTag
-	case *types.Func:
-		return funcTag
-	default:
-		errorf("unexpected object: %v (%T)", obj, obj) // panics
-		panic("unreachable")
-	}
-}
-
-func sameObj(a, b types.Object) bool {
-	// Because unnamed types are not canonicalized, we cannot simply compare types for
-	// (pointer) identity.
-	// Ideally we'd check equality of constant values as well, but this is good enough.
-	return objTag(a) == objTag(b) && types.Identical(a.Type(), b.Type())
-}
-
-func (p *importer) declare(obj types.Object) {
-	pkg := obj.Pkg()
-	if alt := pkg.Scope().Insert(obj); alt != nil {
-		// This can only trigger if we import a (non-type) object a second time.
-		// Excluding type aliases, this cannot happen because 1) we only import a package
-		// once; and b) we ignore compiler-specific export data which may contain
-		// functions whose inlined function bodies refer to other functions that
-		// were already imported.
-		// However, type aliases require reexporting the original type, so we need
-		// to allow it (see also the comment in cmd/compile/internal/gc/bimport.go,
-		// method importer.obj, switch case importing functions).
-		// TODO(gri) review/update this comment once the gc compiler handles type aliases.
-		if !sameObj(obj, alt) {
-			errorf("inconsistent import:\n\t%v\npreviously imported as:\n\t%v\n", obj, alt)
-		}
-	}
-}
-
-func (p *importer) obj(tag int) {
-	switch tag {
-	case constTag:
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		typ := p.typ(nil, nil)
-		val := p.value()
-		p.declare(types.NewConst(pos, pkg, name, typ, val))
-
-	case aliasTag:
-		// TODO(gri) verify type alias hookup is correct
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		typ := p.typ(nil, nil)
-		p.declare(types.NewTypeName(pos, pkg, name, typ))
-
-	case typeTag:
-		p.typ(nil, nil)
-
-	case varTag:
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		typ := p.typ(nil, nil)
-		p.declare(types.NewVar(pos, pkg, name, typ))
-
-	case funcTag:
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		params, isddd := p.paramList()
-		result, _ := p.paramList()
-		sig := types.NewSignature(nil, params, result, isddd)
-		p.declare(types.NewFunc(pos, pkg, name, sig))
-
-	default:
-		errorf("unexpected object tag %d", tag)
-	}
-}
-
-const deltaNewFile = -64 // see cmd/compile/internal/gc/bexport.go
-
-func (p *importer) pos() token.Pos {
-	if !p.posInfoFormat {
-		return token.NoPos
-	}
-
-	file := p.prevFile
-	line := p.prevLine
-	delta := p.int()
-	line += delta
-	if p.version >= 5 {
-		if delta == deltaNewFile {
-			if n := p.int(); n >= 0 {
-				// file changed
-				file = p.path()
-				line = n
-			}
-		}
-	} else {
-		if delta == 0 {
-			if n := p.int(); n >= 0 {
-				// file changed
-				file = p.prevFile[:n] + p.string()
-				line = p.int()
-			}
-		}
-	}
-	p.prevFile = file
-	p.prevLine = line
-
-	return p.fake.pos(file, line, 0)
-}
-
-// Synthesize a token.Pos
-type fakeFileSet struct {
-	fset  *token.FileSet
-	files map[string]*token.File
-}
-
-func (s *fakeFileSet) pos(file string, line, column int) token.Pos {
-	// TODO(mdempsky): Make use of column.
-
-	// Since we don't know the set of needed file positions, we
-	// reserve maxlines positions per file.
-	const maxlines = 64 * 1024
-	f := s.files[file]
-	if f == nil {
-		f = s.fset.AddFile(file, -1, maxlines)
-		s.files[file] = f
-		// Allocate the fake linebreak indices on first use.
-		// TODO(adonovan): opt: save ~512KB using a more complex scheme?
-		fakeLinesOnce.Do(func() {
-			fakeLines = make([]int, maxlines)
-			for i := range fakeLines {
-				fakeLines[i] = i
-			}
-		})
-		f.SetLines(fakeLines)
-	}
-
-	if line > maxlines {
-		line = 1
-	}
-
-	// Treat the file as if it contained only newlines
-	// and column=1: use the line number as the offset.
-	return f.Pos(line - 1)
-}
-
-var (
-	fakeLines     []int
-	fakeLinesOnce sync.Once
-)
-
-func (p *importer) qualifiedName() (pkg *types.Package, name string) {
-	name = p.string()
-	pkg = p.pkg()
-	return
-}
-
-func (p *importer) record(t types.Type) {
-	p.typList = append(p.typList, t)
-}
-
-// A dddSlice is a types.Type representing ...T parameters.
-// It only appears for parameter types and does not escape
-// the importer.
-type dddSlice struct {
-	elem types.Type
-}
-
-func (t *dddSlice) Underlying() types.Type { return t }
-func (t *dddSlice) String() string         { return "..." + t.elem.String() }
-
-// parent is the package which declared the type; parent == nil means
-// the package currently imported. The parent package is needed for
-// exported struct fields and interface methods which don't contain
-// explicit package information in the export data.
-//
-// A non-nil tname is used as the "owner" of the result type; i.e.,
-// the result type is the underlying type of tname. tname is used
-// to give interface methods a named receiver type where possible.
-func (p *importer) typ(parent *types.Package, tname *types.Named) types.Type {
-	// if the type was seen before, i is its index (>= 0)
-	i := p.tagOrIndex()
-	if i >= 0 {
-		return p.typList[i]
-	}
-
-	// otherwise, i is the type tag (< 0)
-	switch i {
-	case namedTag:
-		// read type object
-		pos := p.pos()
-		parent, name := p.qualifiedName()
-		scope := parent.Scope()
-		obj := scope.Lookup(name)
-
-		// if the object doesn't exist yet, create and insert it
-		if obj == nil {
-			obj = types.NewTypeName(pos, parent, name, nil)
-			scope.Insert(obj)
-		}
-
-		if _, ok := obj.(*types.TypeName); !ok {
-			errorf("pkg = %s, name = %s => %s", parent, name, obj)
-		}
-
-		// associate new named type with obj if it doesn't exist yet
-		t0 := types.NewNamed(obj.(*types.TypeName), nil, nil)
-
-		// but record the existing type, if any
-		tname := obj.Type().(*types.Named) // tname is either t0 or the existing type
-		p.record(tname)
-
-		// read underlying type
-		t0.SetUnderlying(p.typ(parent, t0))
-
-		// interfaces don't have associated methods
-		if types.IsInterface(t0) {
-			return tname
-		}
-
-		// read associated methods
-		for i := p.int(); i > 0; i-- {
-			// TODO(gri) replace this with something closer to fieldName
-			pos := p.pos()
-			name := p.string()
-			if !exported(name) {
-				p.pkg()
-			}
-
-			recv, _ := p.paramList() // TODO(gri) do we need a full param list for the receiver?
-			params, isddd := p.paramList()
-			result, _ := p.paramList()
-			p.int() // go:nointerface pragma - discarded
-
-			sig := types.NewSignature(recv.At(0), params, result, isddd)
-			t0.AddMethod(types.NewFunc(pos, parent, name, sig))
-		}
-
-		return tname
-
-	case arrayTag:
-		t := new(types.Array)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		n := p.int64()
-		*t = *types.NewArray(p.typ(parent, nil), n)
-		return t
-
-	case sliceTag:
-		t := new(types.Slice)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		*t = *types.NewSlice(p.typ(parent, nil))
-		return t
-
-	case dddTag:
-		t := new(dddSlice)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		t.elem = p.typ(parent, nil)
-		return t
-
-	case structTag:
-		t := new(types.Struct)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		*t = *types.NewStruct(p.fieldList(parent))
-		return t
-
-	case pointerTag:
-		t := new(types.Pointer)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		*t = *types.NewPointer(p.typ(parent, nil))
-		return t
-
-	case signatureTag:
-		t := new(types.Signature)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		params, isddd := p.paramList()
-		result, _ := p.paramList()
-		*t = *types.NewSignature(nil, params, result, isddd)
-		return t
-
-	case interfaceTag:
-		// Create a dummy entry in the type list. This is safe because we
-		// cannot expect the interface type to appear in a cycle, as any
-		// such cycle must contain a named type which would have been
-		// first defined earlier.
-		// TODO(gri) Is this still true now that we have type aliases?
-		// See issue #23225.
-		n := len(p.typList)
-		if p.trackAllTypes {
-			p.record(nil)
-		}
-
-		var embeddeds []types.Type
-		for n := p.int(); n > 0; n-- {
-			p.pos()
-			embeddeds = append(embeddeds, p.typ(parent, nil))
-		}
-
-		t := newInterface(p.methodList(parent, tname), embeddeds)
-		p.interfaceList = append(p.interfaceList, t)
-		if p.trackAllTypes {
-			p.typList[n] = t
-		}
-		return t
-
-	case mapTag:
-		t := new(types.Map)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		key := p.typ(parent, nil)
-		val := p.typ(parent, nil)
-		*t = *types.NewMap(key, val)
-		return t
-
-	case chanTag:
-		t := new(types.Chan)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		dir := chanDir(p.int())
-		val := p.typ(parent, nil)
-		*t = *types.NewChan(dir, val)
-		return t
-
-	default:
-		errorf("unexpected type tag %d", i) // panics
-		panic("unreachable")
-	}
-}
-
-func chanDir(d int) types.ChanDir {
-	// tag values must match the constants in cmd/compile/internal/gc/go.go
-	switch d {
-	case 1 /* Crecv */ :
-		return types.RecvOnly
-	case 2 /* Csend */ :
-		return types.SendOnly
-	case 3 /* Cboth */ :
-		return types.SendRecv
-	default:
-		errorf("unexpected channel dir %d", d)
-		return 0
-	}
-}
-
-func (p *importer) fieldList(parent *types.Package) (fields []*types.Var, tags []string) {
-	if n := p.int(); n > 0 {
-		fields = make([]*types.Var, n)
-		tags = make([]string, n)
-		for i := range fields {
-			fields[i], tags[i] = p.field(parent)
-		}
-	}
-	return
-}
-
-func (p *importer) field(parent *types.Package) (*types.Var, string) {
-	pos := p.pos()
-	pkg, name, alias := p.fieldName(parent)
-	typ := p.typ(parent, nil)
-	tag := p.string()
-
-	anonymous := false
-	if name == "" {
-		// anonymous field - typ must be T or *T and T must be a type name
-		switch typ := deref(typ).(type) {
-		case *types.Basic: // basic types are named types
-			pkg = nil // // objects defined in Universe scope have no package
-			name = typ.Name()
-		case *types.Named:
-			name = typ.Obj().Name()
-		default:
-			errorf("named base type expected")
-		}
-		anonymous = true
-	} else if alias {
-		// anonymous field: we have an explicit name because it's an alias
-		anonymous = true
-	}
-
-	return types.NewField(pos, pkg, name, typ, anonymous), tag
-}
-
-func (p *importer) methodList(parent *types.Package, baseType *types.Named) (methods []*types.Func) {
-	if n := p.int(); n > 0 {
-		methods = make([]*types.Func, n)
-		for i := range methods {
-			methods[i] = p.method(parent, baseType)
-		}
-	}
-	return
-}
-
-func (p *importer) method(parent *types.Package, baseType *types.Named) *types.Func {
-	pos := p.pos()
-	pkg, name, _ := p.fieldName(parent)
-	// If we don't have a baseType, use a nil receiver.
-	// A receiver using the actual interface type (which
-	// we don't know yet) will be filled in when we call
-	// types.Interface.Complete.
-	var recv *types.Var
-	if baseType != nil {
-		recv = types.NewVar(token.NoPos, parent, "", baseType)
-	}
-	params, isddd := p.paramList()
-	result, _ := p.paramList()
-	sig := types.NewSignature(recv, params, result, isddd)
-	return types.NewFunc(pos, pkg, name, sig)
-}
-
-func (p *importer) fieldName(parent *types.Package) (pkg *types.Package, name string, alias bool) {
-	name = p.string()
-	pkg = parent
-	if pkg == nil {
-		// use the imported package instead
-		pkg = p.pkgList[0]
-	}
-	if p.version == 0 && name == "_" {
-		// version 0 didn't export a package for _ fields
-		return
-	}
-	switch name {
-	case "":
-		// 1) field name matches base type name and is exported: nothing to do
-	case "?":
-		// 2) field name matches base type name and is not exported: need package
-		name = ""
-		pkg = p.pkg()
-	case "@":
-		// 3) field name doesn't match type name (alias)
-		name = p.string()
-		alias = true
-		fallthrough
-	default:
-		if !exported(name) {
-			pkg = p.pkg()
-		}
-	}
-	return
-}
-
-func (p *importer) paramList() (*types.Tuple, bool) {
-	n := p.int()
-	if n == 0 {
-		return nil, false
-	}
-	// negative length indicates unnamed parameters
-	named := true
-	if n < 0 {
-		n = -n
-		named = false
-	}
-	// n > 0
-	params := make([]*types.Var, n)
-	isddd := false
-	for i := range params {
-		params[i], isddd = p.param(named)
-	}
-	return types.NewTuple(params...), isddd
-}
-
-func (p *importer) param(named bool) (*types.Var, bool) {
-	t := p.typ(nil, nil)
-	td, isddd := t.(*dddSlice)
-	if isddd {
-		t = types.NewSlice(td.elem)
-	}
-
-	var pkg *types.Package
-	var name string
-	if named {
-		name = p.string()
-		if name == "" {
-			errorf("expected named parameter")
-		}
-		if name != "_" {
-			pkg = p.pkg()
-		}
-		if i := strings.Index(name, "·"); i > 0 {
-			name = name[:i] // cut off gc-specific parameter numbering
-		}
-	}
-
-	// read and discard compiler-specific info
-	p.string()
-
-	return types.NewVar(token.NoPos, pkg, name, t), isddd
-}
-
-func exported(name string) bool {
-	ch, _ := utf8.DecodeRuneInString(name)
-	return unicode.IsUpper(ch)
-}
-
-func (p *importer) value() constant.Value {
-	switch tag := p.tagOrIndex(); tag {
-	case falseTag:
-		return constant.MakeBool(false)
-	case trueTag:
-		return constant.MakeBool(true)
-	case int64Tag:
-		return constant.MakeInt64(p.int64())
-	case floatTag:
-		return p.float()
-	case complexTag:
-		re := p.float()
-		im := p.float()
-		return constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
-	case stringTag:
-		return constant.MakeString(p.string())
-	case unknownTag:
-		return constant.MakeUnknown()
-	default:
-		errorf("unexpected value tag %d", tag) // panics
-		panic("unreachable")
-	}
-}
-
-func (p *importer) float() constant.Value {
-	sign := p.int()
-	if sign == 0 {
-		return constant.MakeInt64(0)
-	}
-
-	exp := p.int()
-	mant := []byte(p.string()) // big endian
-
-	// remove leading 0's if any
-	for len(mant) > 0 && mant[0] == 0 {
-		mant = mant[1:]
-	}
-
-	// convert to little endian
-	// TODO(gri) go/constant should have a more direct conversion function
-	//           (e.g., once it supports a big.Float based implementation)
-	for i, j := 0, len(mant)-1; i < j; i, j = i+1, j-1 {
-		mant[i], mant[j] = mant[j], mant[i]
-	}
-
-	// adjust exponent (constant.MakeFromBytes creates an integer value,
-	// but mant represents the mantissa bits such that 0.5 <= mant < 1.0)
-	exp -= len(mant) << 3
-	if len(mant) > 0 {
-		for msd := mant[len(mant)-1]; msd&0x80 == 0; msd <<= 1 {
-			exp++
-		}
-	}
-
-	x := constant.MakeFromBytes(mant)
-	switch {
-	case exp < 0:
-		d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp))
-		x = constant.BinaryOp(x, token.QUO, d)
-	case exp > 0:
-		x = constant.Shift(x, token.SHL, uint(exp))
-	}
-
-	if sign < 0 {
-		x = constant.UnaryOp(token.SUB, x, 0)
-	}
-	return x
-}
-
-// ----------------------------------------------------------------------------
-// Low-level decoders
-
-func (p *importer) tagOrIndex() int {
-	if p.debugFormat {
-		p.marker('t')
-	}
-
-	return int(p.rawInt64())
-}
-
-func (p *importer) int() int {
-	x := p.int64()
-	if int64(int(x)) != x {
-		errorf("exported integer too large")
-	}
-	return int(x)
-}
-
-func (p *importer) int64() int64 {
-	if p.debugFormat {
-		p.marker('i')
-	}
-
-	return p.rawInt64()
-}
-
-func (p *importer) path() string {
-	if p.debugFormat {
-		p.marker('p')
-	}
-	// if the path was seen before, i is its index (>= 0)
-	// (the empty string is at index 0)
-	i := p.rawInt64()
-	if i >= 0 {
-		return p.pathList[i]
-	}
-	// otherwise, i is the negative path length (< 0)
-	a := make([]string, -i)
-	for n := range a {
-		a[n] = p.string()
-	}
-	s := strings.Join(a, "/")
-	p.pathList = append(p.pathList, s)
-	return s
-}
-
-func (p *importer) string() string {
-	if p.debugFormat {
-		p.marker('s')
-	}
-	// if the string was seen before, i is its index (>= 0)
-	// (the empty string is at index 0)
-	i := p.rawInt64()
-	if i >= 0 {
-		return p.strList[i]
-	}
-	// otherwise, i is the negative string length (< 0)
-	if n := int(-i); n <= cap(p.buf) {
-		p.buf = p.buf[:n]
-	} else {
-		p.buf = make([]byte, n)
-	}
-	for i := range p.buf {
-		p.buf[i] = p.rawByte()
-	}
-	s := string(p.buf)
-	p.strList = append(p.strList, s)
-	return s
-}
-
-func (p *importer) marker(want byte) {
-	if got := p.rawByte(); got != want {
-		errorf("incorrect marker: got %c; want %c (pos = %d)", got, want, p.read)
-	}
-
-	pos := p.read
-	if n := int(p.rawInt64()); n != pos {
-		errorf("incorrect position: got %d; want %d", n, pos)
-	}
-}
-
-// rawInt64 should only be used by low-level decoders.
-func (p *importer) rawInt64() int64 {
-	i, err := binary.ReadVarint(p)
-	if err != nil {
-		errorf("read error: %v", err)
-	}
-	return i
-}
-
-// rawStringln should only be used to read the initial version string.
-func (p *importer) rawStringln(b byte) string {
-	p.buf = p.buf[:0]
-	for b != '\n' {
-		p.buf = append(p.buf, b)
-		b = p.rawByte()
-	}
-	return string(p.buf)
-}
-
-// needed for binary.ReadVarint in rawInt64
-func (p *importer) ReadByte() (byte, error) {
-	return p.rawByte(), nil
-}
-
-// byte is the bottleneck interface for reading p.data.
-// It unescapes '|' 'S' to '$' and '|' '|' to '|'.
-// rawByte should only be used by low-level decoders.
-func (p *importer) rawByte() byte {
-	b := p.data[0]
-	r := 1
-	if b == '|' {
-		b = p.data[1]
-		r = 2
-		switch b {
-		case 'S':
-			b = '$'
-		case '|':
-			// nothing to do
-		default:
-			errorf("unexpected escape sequence in export data")
-		}
-	}
-	p.data = p.data[r:]
-	p.read += r
-	return b
-
-}
-
-// ----------------------------------------------------------------------------
-// Export format
-
-// Tags. Must be < 0.
-const (
-	// Objects
-	packageTag = -(iota + 1)
-	constTag
-	typeTag
-	varTag
-	funcTag
-	endTag
-
-	// Types
-	namedTag
-	arrayTag
-	sliceTag
-	dddTag
-	structTag
-	pointerTag
-	signatureTag
-	interfaceTag
-	mapTag
-	chanTag
-
-	// Values
-	falseTag
-	trueTag
-	int64Tag
-	floatTag
-	fractionTag // not used by gc
-	complexTag
-	stringTag
-	nilTag     // only used by gc (appears in exported inlined function bodies)
-	unknownTag // not used by gc (only appears in packages with errors)
-
-	// Type aliases
-	aliasTag
-)
-
-var predeclOnce sync.Once
-var predecl []types.Type // initialized lazily
-
-func predeclared() []types.Type {
-	predeclOnce.Do(func() {
-		// initialize lazily to be sure that all
-		// elements have been initialized before
-		predecl = []types.Type{ // basic types
-			types.Typ[types.Bool],
-			types.Typ[types.Int],
-			types.Typ[types.Int8],
-			types.Typ[types.Int16],
-			types.Typ[types.Int32],
-			types.Typ[types.Int64],
-			types.Typ[types.Uint],
-			types.Typ[types.Uint8],
-			types.Typ[types.Uint16],
-			types.Typ[types.Uint32],
-			types.Typ[types.Uint64],
-			types.Typ[types.Uintptr],
-			types.Typ[types.Float32],
-			types.Typ[types.Float64],
-			types.Typ[types.Complex64],
-			types.Typ[types.Complex128],
-			types.Typ[types.String],
-
-			// basic type aliases
-			types.Universe.Lookup("byte").Type(),
-			types.Universe.Lookup("rune").Type(),
-
-			// error
-			types.Universe.Lookup("error").Type(),
-
-			// untyped types
-			types.Typ[types.UntypedBool],
-			types.Typ[types.UntypedInt],
-			types.Typ[types.UntypedRune],
-			types.Typ[types.UntypedFloat],
-			types.Typ[types.UntypedComplex],
-			types.Typ[types.UntypedString],
-			types.Typ[types.UntypedNil],
-
-			// package unsafe
-			types.Typ[types.UnsafePointer],
-
-			// invalid type
-			types.Typ[types.Invalid], // only appears in packages with errors
-
-			// used internally by gc; never used by this package or in .a files
-			anyType{},
-		}
-	})
-	return predecl
-}
-
-type anyType struct{}
-
-func (t anyType) Underlying() types.Type { return t }
-func (t anyType) String() string         { return "any" }
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/exportdata.go b/vendor/golang.org/x/tools/go/internal/gcimporter/exportdata.go
deleted file mode 100644
index f33dc5613e..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/exportdata.go
+++ /dev/null
@@ -1,93 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file is a copy of $GOROOT/src/go/internal/gcimporter/exportdata.go.
-
-// This file implements FindExportData.
-
-package gcimporter
-
-import (
-	"bufio"
-	"fmt"
-	"io"
-	"strconv"
-	"strings"
-)
-
-func readGopackHeader(r *bufio.Reader) (name string, size int, err error) {
-	// See $GOROOT/include/ar.h.
-	hdr := make([]byte, 16+12+6+6+8+10+2)
-	_, err = io.ReadFull(r, hdr)
-	if err != nil {
-		return
-	}
-	// leave for debugging
-	if false {
-		fmt.Printf("header: %s", hdr)
-	}
-	s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))
-	size, err = strconv.Atoi(s)
-	if err != nil || hdr[len(hdr)-2] != '`' || hdr[len(hdr)-1] != '\n' {
-		err = fmt.Errorf("invalid archive header")
-		return
-	}
-	name = strings.TrimSpace(string(hdr[:16]))
-	return
-}
-
-// FindExportData positions the reader r at the beginning of the
-// export data section of an underlying GC-created object/archive
-// file by reading from it. The reader must be positioned at the
-// start of the file before calling this function. The hdr result
-// is the string before the export data, either "$$" or "$$B".
-//
-func FindExportData(r *bufio.Reader) (hdr string, err error) {
-	// Read first line to make sure this is an object file.
-	line, err := r.ReadSlice('\n')
-	if err != nil {
-		err = fmt.Errorf("can't find export data (%v)", err)
-		return
-	}
-
-	if string(line) == "!<arch>\n" {
-		// Archive file. Scan to __.PKGDEF.
-		var name string
-		if name, _, err = readGopackHeader(r); err != nil {
-			return
-		}
-
-		// First entry should be __.PKGDEF.
-		if name != "__.PKGDEF" {
-			err = fmt.Errorf("go archive is missing __.PKGDEF")
-			return
-		}
-
-		// Read first line of __.PKGDEF data, so that line
-		// is once again the first line of the input.
-		if line, err = r.ReadSlice('\n'); err != nil {
-			err = fmt.Errorf("can't find export data (%v)", err)
-			return
-		}
-	}
-
-	// Now at __.PKGDEF in archive or still at beginning of file.
-	// Either way, line should begin with "go object ".
-	if !strings.HasPrefix(string(line), "go object ") {
-		err = fmt.Errorf("not a Go object file")
-		return
-	}
-
-	// Skip over object header to export data.
-	// Begins after first line starting with $$.
-	for line[0] != '$' {
-		if line, err = r.ReadSlice('\n'); err != nil {
-			err = fmt.Errorf("can't find export data (%v)", err)
-			return
-		}
-	}
-	hdr = string(line)
-
-	return
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go b/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go
deleted file mode 100644
index e8cba6b237..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go
+++ /dev/null
@@ -1,1078 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file is a modified copy of $GOROOT/src/go/internal/gcimporter/gcimporter.go,
-// but it also contains the original source-based importer code for Go1.6.
-// Once we stop supporting 1.6, we can remove that code.
-
-// Package gcimporter provides various functions for reading
-// gc-generated object files that can be used to implement the
-// Importer interface defined by the Go 1.5 standard library package.
-package gcimporter // import "golang.org/x/tools/go/internal/gcimporter"
-
-import (
-	"bufio"
-	"errors"
-	"fmt"
-	"go/build"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"io"
-	"io/ioutil"
-	"os"
-	"path/filepath"
-	"sort"
-	"strconv"
-	"strings"
-	"text/scanner"
-)
-
-// debugging/development support
-const debug = false
-
-var pkgExts = [...]string{".a", ".o"}
-
-// FindPkg returns the filename and unique package id for an import
-// path based on package information provided by build.Import (using
-// the build.Default build.Context). A relative srcDir is interpreted
-// relative to the current working directory.
-// If no file was found, an empty filename is returned.
-//
-func FindPkg(path, srcDir string) (filename, id string) {
-	if path == "" {
-		return
-	}
-
-	var noext string
-	switch {
-	default:
-		// "x" -> "$GOPATH/pkg/$GOOS_$GOARCH/x.ext", "x"
-		// Don't require the source files to be present.
-		if abs, err := filepath.Abs(srcDir); err == nil { // see issue 14282
-			srcDir = abs
-		}
-		bp, _ := build.Import(path, srcDir, build.FindOnly|build.AllowBinary)
-		if bp.PkgObj == "" {
-			id = path // make sure we have an id to print in error message
-			return
-		}
-		noext = strings.TrimSuffix(bp.PkgObj, ".a")
-		id = bp.ImportPath
-
-	case build.IsLocalImport(path):
-		// "./x" -> "/this/directory/x.ext", "/this/directory/x"
-		noext = filepath.Join(srcDir, path)
-		id = noext
-
-	case filepath.IsAbs(path):
-		// for completeness only - go/build.Import
-		// does not support absolute imports
-		// "/x" -> "/x.ext", "/x"
-		noext = path
-		id = path
-	}
-
-	if false { // for debugging
-		if path != id {
-			fmt.Printf("%s -> %s\n", path, id)
-		}
-	}
-
-	// try extensions
-	for _, ext := range pkgExts {
-		filename = noext + ext
-		if f, err := os.Stat(filename); err == nil && !f.IsDir() {
-			return
-		}
-	}
-
-	filename = "" // not found
-	return
-}
-
-// ImportData imports a package by reading the gc-generated export data,
-// adds the corresponding package object to the packages map indexed by id,
-// and returns the object.
-//
-// The packages map must contains all packages already imported. The data
-// reader position must be the beginning of the export data section. The
-// filename is only used in error messages.
-//
-// If packages[id] contains the completely imported package, that package
-// can be used directly, and there is no need to call this function (but
-// there is also no harm but for extra time used).
-//
-func ImportData(packages map[string]*types.Package, filename, id string, data io.Reader) (pkg *types.Package, err error) {
-	// support for parser error handling
-	defer func() {
-		switch r := recover().(type) {
-		case nil:
-			// nothing to do
-		case importError:
-			err = r
-		default:
-			panic(r) // internal error
-		}
-	}()
-
-	var p parser
-	p.init(filename, id, data, packages)
-	pkg = p.parseExport()
-
-	return
-}
-
-// Import imports a gc-generated package given its import path and srcDir, adds
-// the corresponding package object to the packages map, and returns the object.
-// The packages map must contain all packages already imported.
-//
-func Import(packages map[string]*types.Package, path, srcDir string, lookup func(path string) (io.ReadCloser, error)) (pkg *types.Package, err error) {
-	var rc io.ReadCloser
-	var filename, id string
-	if lookup != nil {
-		// With custom lookup specified, assume that caller has
-		// converted path to a canonical import path for use in the map.
-		if path == "unsafe" {
-			return types.Unsafe, nil
-		}
-		id = path
-
-		// No need to re-import if the package was imported completely before.
-		if pkg = packages[id]; pkg != nil && pkg.Complete() {
-			return
-		}
-		f, err := lookup(path)
-		if err != nil {
-			return nil, err
-		}
-		rc = f
-	} else {
-		filename, id = FindPkg(path, srcDir)
-		if filename == "" {
-			if path == "unsafe" {
-				return types.Unsafe, nil
-			}
-			return nil, fmt.Errorf("can't find import: %q", id)
-		}
-
-		// no need to re-import if the package was imported completely before
-		if pkg = packages[id]; pkg != nil && pkg.Complete() {
-			return
-		}
-
-		// open file
-		f, err := os.Open(filename)
-		if err != nil {
-			return nil, err
-		}
-		defer func() {
-			if err != nil {
-				// add file name to error
-				err = fmt.Errorf("%s: %v", filename, err)
-			}
-		}()
-		rc = f
-	}
-	defer rc.Close()
-
-	var hdr string
-	buf := bufio.NewReader(rc)
-	if hdr, err = FindExportData(buf); err != nil {
-		return
-	}
-
-	switch hdr {
-	case "$$\n":
-		// Work-around if we don't have a filename; happens only if lookup != nil.
-		// Either way, the filename is only needed for importer error messages, so
-		// this is fine.
-		if filename == "" {
-			filename = path
-		}
-		return ImportData(packages, filename, id, buf)
-
-	case "$$B\n":
-		var data []byte
-		data, err = ioutil.ReadAll(buf)
-		if err != nil {
-			break
-		}
-
-		// TODO(gri): allow clients of go/importer to provide a FileSet.
-		// Or, define a new standard go/types/gcexportdata package.
-		fset := token.NewFileSet()
-
-		// The indexed export format starts with an 'i'; the older
-		// binary export format starts with a 'c', 'd', or 'v'
-		// (from "version"). Select appropriate importer.
-		if len(data) > 0 && data[0] == 'i' {
-			_, pkg, err = IImportData(fset, packages, data[1:], id)
-		} else {
-			_, pkg, err = BImportData(fset, packages, data, id)
-		}
-
-	default:
-		err = fmt.Errorf("unknown export data header: %q", hdr)
-	}
-
-	return
-}
-
-// ----------------------------------------------------------------------------
-// Parser
-
-// TODO(gri) Imported objects don't have position information.
-//           Ideally use the debug table line info; alternatively
-//           create some fake position (or the position of the
-//           import). That way error messages referring to imported
-//           objects can print meaningful information.
-
-// parser parses the exports inside a gc compiler-produced
-// object/archive file and populates its scope with the results.
-type parser struct {
-	scanner    scanner.Scanner
-	tok        rune                      // current token
-	lit        string                    // literal string; only valid for Ident, Int, String tokens
-	id         string                    // package id of imported package
-	sharedPkgs map[string]*types.Package // package id -> package object (across importer)
-	localPkgs  map[string]*types.Package // package id -> package object (just this package)
-}
-
-func (p *parser) init(filename, id string, src io.Reader, packages map[string]*types.Package) {
-	p.scanner.Init(src)
-	p.scanner.Error = func(_ *scanner.Scanner, msg string) { p.error(msg) }
-	p.scanner.Mode = scanner.ScanIdents | scanner.ScanInts | scanner.ScanChars | scanner.ScanStrings | scanner.ScanComments | scanner.SkipComments
-	p.scanner.Whitespace = 1<<'\t' | 1<<' '
-	p.scanner.Filename = filename // for good error messages
-	p.next()
-	p.id = id
-	p.sharedPkgs = packages
-	if debug {
-		// check consistency of packages map
-		for _, pkg := range packages {
-			if pkg.Name() == "" {
-				fmt.Printf("no package name for %s\n", pkg.Path())
-			}
-		}
-	}
-}
-
-func (p *parser) next() {
-	p.tok = p.scanner.Scan()
-	switch p.tok {
-	case scanner.Ident, scanner.Int, scanner.Char, scanner.String, '·':
-		p.lit = p.scanner.TokenText()
-	default:
-		p.lit = ""
-	}
-	if debug {
-		fmt.Printf("%s: %q -> %q\n", scanner.TokenString(p.tok), p.scanner.TokenText(), p.lit)
-	}
-}
-
-func declTypeName(pkg *types.Package, name string) *types.TypeName {
-	scope := pkg.Scope()
-	if obj := scope.Lookup(name); obj != nil {
-		return obj.(*types.TypeName)
-	}
-	obj := types.NewTypeName(token.NoPos, pkg, name, nil)
-	// a named type may be referred to before the underlying type
-	// is known - set it up
-	types.NewNamed(obj, nil, nil)
-	scope.Insert(obj)
-	return obj
-}
-
-// ----------------------------------------------------------------------------
-// Error handling
-
-// Internal errors are boxed as importErrors.
-type importError struct {
-	pos scanner.Position
-	err error
-}
-
-func (e importError) Error() string {
-	return fmt.Sprintf("import error %s (byte offset = %d): %s", e.pos, e.pos.Offset, e.err)
-}
-
-func (p *parser) error(err interface{}) {
-	if s, ok := err.(string); ok {
-		err = errors.New(s)
-	}
-	// panic with a runtime.Error if err is not an error
-	panic(importError{p.scanner.Pos(), err.(error)})
-}
-
-func (p *parser) errorf(format string, args ...interface{}) {
-	p.error(fmt.Sprintf(format, args...))
-}
-
-func (p *parser) expect(tok rune) string {
-	lit := p.lit
-	if p.tok != tok {
-		p.errorf("expected %s, got %s (%s)", scanner.TokenString(tok), scanner.TokenString(p.tok), lit)
-	}
-	p.next()
-	return lit
-}
-
-func (p *parser) expectSpecial(tok string) {
-	sep := 'x' // not white space
-	i := 0
-	for i < len(tok) && p.tok == rune(tok[i]) && sep > ' ' {
-		sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token
-		p.next()
-		i++
-	}
-	if i < len(tok) {
-		p.errorf("expected %q, got %q", tok, tok[0:i])
-	}
-}
-
-func (p *parser) expectKeyword(keyword string) {
-	lit := p.expect(scanner.Ident)
-	if lit != keyword {
-		p.errorf("expected keyword %s, got %q", keyword, lit)
-	}
-}
-
-// ----------------------------------------------------------------------------
-// Qualified and unqualified names
-
-// PackageId = string_lit .
-//
-func (p *parser) parsePackageID() string {
-	id, err := strconv.Unquote(p.expect(scanner.String))
-	if err != nil {
-		p.error(err)
-	}
-	// id == "" stands for the imported package id
-	// (only known at time of package installation)
-	if id == "" {
-		id = p.id
-	}
-	return id
-}
-
-// PackageName = ident .
-//
-func (p *parser) parsePackageName() string {
-	return p.expect(scanner.Ident)
-}
-
-// dotIdentifier = ( ident | '·' ) { ident | int | '·' } .
-func (p *parser) parseDotIdent() string {
-	ident := ""
-	if p.tok != scanner.Int {
-		sep := 'x' // not white space
-		for (p.tok == scanner.Ident || p.tok == scanner.Int || p.tok == '·') && sep > ' ' {
-			ident += p.lit
-			sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token
-			p.next()
-		}
-	}
-	if ident == "" {
-		p.expect(scanner.Ident) // use expect() for error handling
-	}
-	return ident
-}
-
-// QualifiedName = "@" PackageId "." ( "?" | dotIdentifier ) .
-//
-func (p *parser) parseQualifiedName() (id, name string) {
-	p.expect('@')
-	id = p.parsePackageID()
-	p.expect('.')
-	// Per rev f280b8a485fd (10/2/2013), qualified names may be used for anonymous fields.
-	if p.tok == '?' {
-		p.next()
-	} else {
-		name = p.parseDotIdent()
-	}
-	return
-}
-
-// getPkg returns the package for a given id. If the package is
-// not found, create the package and add it to the p.localPkgs
-// and p.sharedPkgs maps. name is the (expected) name of the
-// package. If name == "", the package name is expected to be
-// set later via an import clause in the export data.
-//
-// id identifies a package, usually by a canonical package path like
-// "encoding/json" but possibly by a non-canonical import path like
-// "./json".
-//
-func (p *parser) getPkg(id, name string) *types.Package {
-	// package unsafe is not in the packages maps - handle explicitly
-	if id == "unsafe" {
-		return types.Unsafe
-	}
-
-	pkg := p.localPkgs[id]
-	if pkg == nil {
-		// first import of id from this package
-		pkg = p.sharedPkgs[id]
-		if pkg == nil {
-			// first import of id by this importer;
-			// add (possibly unnamed) pkg to shared packages
-			pkg = types.NewPackage(id, name)
-			p.sharedPkgs[id] = pkg
-		}
-		// add (possibly unnamed) pkg to local packages
-		if p.localPkgs == nil {
-			p.localPkgs = make(map[string]*types.Package)
-		}
-		p.localPkgs[id] = pkg
-	} else if name != "" {
-		// package exists already and we have an expected package name;
-		// make sure names match or set package name if necessary
-		if pname := pkg.Name(); pname == "" {
-			pkg.SetName(name)
-		} else if pname != name {
-			p.errorf("%s package name mismatch: %s (given) vs %s (expected)", id, pname, name)
-		}
-	}
-	return pkg
-}
-
-// parseExportedName is like parseQualifiedName, but
-// the package id is resolved to an imported *types.Package.
-//
-func (p *parser) parseExportedName() (pkg *types.Package, name string) {
-	id, name := p.parseQualifiedName()
-	pkg = p.getPkg(id, "")
-	return
-}
-
-// ----------------------------------------------------------------------------
-// Types
-
-// BasicType = identifier .
-//
-func (p *parser) parseBasicType() types.Type {
-	id := p.expect(scanner.Ident)
-	obj := types.Universe.Lookup(id)
-	if obj, ok := obj.(*types.TypeName); ok {
-		return obj.Type()
-	}
-	p.errorf("not a basic type: %s", id)
-	return nil
-}
-
-// ArrayType = "[" int_lit "]" Type .
-//
-func (p *parser) parseArrayType(parent *types.Package) types.Type {
-	// "[" already consumed and lookahead known not to be "]"
-	lit := p.expect(scanner.Int)
-	p.expect(']')
-	elem := p.parseType(parent)
-	n, err := strconv.ParseInt(lit, 10, 64)
-	if err != nil {
-		p.error(err)
-	}
-	return types.NewArray(elem, n)
-}
-
-// MapType = "map" "[" Type "]" Type .
-//
-func (p *parser) parseMapType(parent *types.Package) types.Type {
-	p.expectKeyword("map")
-	p.expect('[')
-	key := p.parseType(parent)
-	p.expect(']')
-	elem := p.parseType(parent)
-	return types.NewMap(key, elem)
-}
-
-// Name = identifier | "?" | QualifiedName .
-//
-// For unqualified and anonymous names, the returned package is the parent
-// package unless parent == nil, in which case the returned package is the
-// package being imported. (The parent package is not nil if the name
-// is an unqualified struct field or interface method name belonging to a
-// type declared in another package.)
-//
-// For qualified names, the returned package is nil (and not created if
-// it doesn't exist yet) unless materializePkg is set (which creates an
-// unnamed package with valid package path). In the latter case, a
-// subsequent import clause is expected to provide a name for the package.
-//
-func (p *parser) parseName(parent *types.Package, materializePkg bool) (pkg *types.Package, name string) {
-	pkg = parent
-	if pkg == nil {
-		pkg = p.sharedPkgs[p.id]
-	}
-	switch p.tok {
-	case scanner.Ident:
-		name = p.lit
-		p.next()
-	case '?':
-		// anonymous
-		p.next()
-	case '@':
-		// exported name prefixed with package path
-		pkg = nil
-		var id string
-		id, name = p.parseQualifiedName()
-		if materializePkg {
-			pkg = p.getPkg(id, "")
-		}
-	default:
-		p.error("name expected")
-	}
-	return
-}
-
-func deref(typ types.Type) types.Type {
-	if p, _ := typ.(*types.Pointer); p != nil {
-		return p.Elem()
-	}
-	return typ
-}
-
-// Field = Name Type [ string_lit ] .
-//
-func (p *parser) parseField(parent *types.Package) (*types.Var, string) {
-	pkg, name := p.parseName(parent, true)
-
-	if name == "_" {
-		// Blank fields should be package-qualified because they
-		// are unexported identifiers, but gc does not qualify them.
-		// Assuming that the ident belongs to the current package
-		// causes types to change during re-exporting, leading
-		// to spurious "can't assign A to B" errors from go/types.
-		// As a workaround, pretend all blank fields belong
-		// to the same unique dummy package.
-		const blankpkg = "<_>"
-		pkg = p.getPkg(blankpkg, blankpkg)
-	}
-
-	typ := p.parseType(parent)
-	anonymous := false
-	if name == "" {
-		// anonymous field - typ must be T or *T and T must be a type name
-		switch typ := deref(typ).(type) {
-		case *types.Basic: // basic types are named types
-			pkg = nil // objects defined in Universe scope have no package
-			name = typ.Name()
-		case *types.Named:
-			name = typ.Obj().Name()
-		default:
-			p.errorf("anonymous field expected")
-		}
-		anonymous = true
-	}
-	tag := ""
-	if p.tok == scanner.String {
-		s := p.expect(scanner.String)
-		var err error
-		tag, err = strconv.Unquote(s)
-		if err != nil {
-			p.errorf("invalid struct tag %s: %s", s, err)
-		}
-	}
-	return types.NewField(token.NoPos, pkg, name, typ, anonymous), tag
-}
-
-// StructType = "struct" "{" [ FieldList ] "}" .
-// FieldList  = Field { ";" Field } .
-//
-func (p *parser) parseStructType(parent *types.Package) types.Type {
-	var fields []*types.Var
-	var tags []string
-
-	p.expectKeyword("struct")
-	p.expect('{')
-	for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ {
-		if i > 0 {
-			p.expect(';')
-		}
-		fld, tag := p.parseField(parent)
-		if tag != "" && tags == nil {
-			tags = make([]string, i)
-		}
-		if tags != nil {
-			tags = append(tags, tag)
-		}
-		fields = append(fields, fld)
-	}
-	p.expect('}')
-
-	return types.NewStruct(fields, tags)
-}
-
-// Parameter = ( identifier | "?" ) [ "..." ] Type [ string_lit ] .
-//
-func (p *parser) parseParameter() (par *types.Var, isVariadic bool) {
-	_, name := p.parseName(nil, false)
-	// remove gc-specific parameter numbering
-	if i := strings.Index(name, "·"); i >= 0 {
-		name = name[:i]
-	}
-	if p.tok == '.' {
-		p.expectSpecial("...")
-		isVariadic = true
-	}
-	typ := p.parseType(nil)
-	if isVariadic {
-		typ = types.NewSlice(typ)
-	}
-	// ignore argument tag (e.g. "noescape")
-	if p.tok == scanner.String {
-		p.next()
-	}
-	// TODO(gri) should we provide a package?
-	par = types.NewVar(token.NoPos, nil, name, typ)
-	return
-}
-
-// Parameters    = "(" [ ParameterList ] ")" .
-// ParameterList = { Parameter "," } Parameter .
-//
-func (p *parser) parseParameters() (list []*types.Var, isVariadic bool) {
-	p.expect('(')
-	for p.tok != ')' && p.tok != scanner.EOF {
-		if len(list) > 0 {
-			p.expect(',')
-		}
-		par, variadic := p.parseParameter()
-		list = append(list, par)
-		if variadic {
-			if isVariadic {
-				p.error("... not on final argument")
-			}
-			isVariadic = true
-		}
-	}
-	p.expect(')')
-
-	return
-}
-
-// Signature = Parameters [ Result ] .
-// Result    = Type | Parameters .
-//
-func (p *parser) parseSignature(recv *types.Var) *types.Signature {
-	params, isVariadic := p.parseParameters()
-
-	// optional result type
-	var results []*types.Var
-	if p.tok == '(' {
-		var variadic bool
-		results, variadic = p.parseParameters()
-		if variadic {
-			p.error("... not permitted on result type")
-		}
-	}
-
-	return types.NewSignature(recv, types.NewTuple(params...), types.NewTuple(results...), isVariadic)
-}
-
-// InterfaceType = "interface" "{" [ MethodList ] "}" .
-// MethodList    = Method { ";" Method } .
-// Method        = Name Signature .
-//
-// The methods of embedded interfaces are always "inlined"
-// by the compiler and thus embedded interfaces are never
-// visible in the export data.
-//
-func (p *parser) parseInterfaceType(parent *types.Package) types.Type {
-	var methods []*types.Func
-
-	p.expectKeyword("interface")
-	p.expect('{')
-	for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ {
-		if i > 0 {
-			p.expect(';')
-		}
-		pkg, name := p.parseName(parent, true)
-		sig := p.parseSignature(nil)
-		methods = append(methods, types.NewFunc(token.NoPos, pkg, name, sig))
-	}
-	p.expect('}')
-
-	// Complete requires the type's embedded interfaces to be fully defined,
-	// but we do not define any
-	return newInterface(methods, nil).Complete()
-}
-
-// ChanType = ( "chan" [ "<-" ] | "<-" "chan" ) Type .
-//
-func (p *parser) parseChanType(parent *types.Package) types.Type {
-	dir := types.SendRecv
-	if p.tok == scanner.Ident {
-		p.expectKeyword("chan")
-		if p.tok == '<' {
-			p.expectSpecial("<-")
-			dir = types.SendOnly
-		}
-	} else {
-		p.expectSpecial("<-")
-		p.expectKeyword("chan")
-		dir = types.RecvOnly
-	}
-	elem := p.parseType(parent)
-	return types.NewChan(dir, elem)
-}
-
-// Type =
-//	BasicType | TypeName | ArrayType | SliceType | StructType |
-//      PointerType | FuncType | InterfaceType | MapType | ChanType |
-//      "(" Type ")" .
-//
-// BasicType   = ident .
-// TypeName    = ExportedName .
-// SliceType   = "[" "]" Type .
-// PointerType = "*" Type .
-// FuncType    = "func" Signature .
-//
-func (p *parser) parseType(parent *types.Package) types.Type {
-	switch p.tok {
-	case scanner.Ident:
-		switch p.lit {
-		default:
-			return p.parseBasicType()
-		case "struct":
-			return p.parseStructType(parent)
-		case "func":
-			// FuncType
-			p.next()
-			return p.parseSignature(nil)
-		case "interface":
-			return p.parseInterfaceType(parent)
-		case "map":
-			return p.parseMapType(parent)
-		case "chan":
-			return p.parseChanType(parent)
-		}
-	case '@':
-		// TypeName
-		pkg, name := p.parseExportedName()
-		return declTypeName(pkg, name).Type()
-	case '[':
-		p.next() // look ahead
-		if p.tok == ']' {
-			// SliceType
-			p.next()
-			return types.NewSlice(p.parseType(parent))
-		}
-		return p.parseArrayType(parent)
-	case '*':
-		// PointerType
-		p.next()
-		return types.NewPointer(p.parseType(parent))
-	case '<':
-		return p.parseChanType(parent)
-	case '(':
-		// "(" Type ")"
-		p.next()
-		typ := p.parseType(parent)
-		p.expect(')')
-		return typ
-	}
-	p.errorf("expected type, got %s (%q)", scanner.TokenString(p.tok), p.lit)
-	return nil
-}
-
-// ----------------------------------------------------------------------------
-// Declarations
-
-// ImportDecl = "import" PackageName PackageId .
-//
-func (p *parser) parseImportDecl() {
-	p.expectKeyword("import")
-	name := p.parsePackageName()
-	p.getPkg(p.parsePackageID(), name)
-}
-
-// int_lit = [ "+" | "-" ] { "0" ... "9" } .
-//
-func (p *parser) parseInt() string {
-	s := ""
-	switch p.tok {
-	case '-':
-		s = "-"
-		p.next()
-	case '+':
-		p.next()
-	}
-	return s + p.expect(scanner.Int)
-}
-
-// number = int_lit [ "p" int_lit ] .
-//
-func (p *parser) parseNumber() (typ *types.Basic, val constant.Value) {
-	// mantissa
-	mant := constant.MakeFromLiteral(p.parseInt(), token.INT, 0)
-	if mant == nil {
-		panic("invalid mantissa")
-	}
-
-	if p.lit == "p" {
-		// exponent (base 2)
-		p.next()
-		exp, err := strconv.ParseInt(p.parseInt(), 10, 0)
-		if err != nil {
-			p.error(err)
-		}
-		if exp < 0 {
-			denom := constant.MakeInt64(1)
-			denom = constant.Shift(denom, token.SHL, uint(-exp))
-			typ = types.Typ[types.UntypedFloat]
-			val = constant.BinaryOp(mant, token.QUO, denom)
-			return
-		}
-		if exp > 0 {
-			mant = constant.Shift(mant, token.SHL, uint(exp))
-		}
-		typ = types.Typ[types.UntypedFloat]
-		val = mant
-		return
-	}
-
-	typ = types.Typ[types.UntypedInt]
-	val = mant
-	return
-}
-
-// ConstDecl   = "const" ExportedName [ Type ] "=" Literal .
-// Literal     = bool_lit | int_lit | float_lit | complex_lit | rune_lit | string_lit .
-// bool_lit    = "true" | "false" .
-// complex_lit = "(" float_lit "+" float_lit "i" ")" .
-// rune_lit    = "(" int_lit "+" int_lit ")" .
-// string_lit  = `"` { unicode_char } `"` .
-//
-func (p *parser) parseConstDecl() {
-	p.expectKeyword("const")
-	pkg, name := p.parseExportedName()
-
-	var typ0 types.Type
-	if p.tok != '=' {
-		// constant types are never structured - no need for parent type
-		typ0 = p.parseType(nil)
-	}
-
-	p.expect('=')
-	var typ types.Type
-	var val constant.Value
-	switch p.tok {
-	case scanner.Ident:
-		// bool_lit
-		if p.lit != "true" && p.lit != "false" {
-			p.error("expected true or false")
-		}
-		typ = types.Typ[types.UntypedBool]
-		val = constant.MakeBool(p.lit == "true")
-		p.next()
-
-	case '-', scanner.Int:
-		// int_lit
-		typ, val = p.parseNumber()
-
-	case '(':
-		// complex_lit or rune_lit
-		p.next()
-		if p.tok == scanner.Char {
-			p.next()
-			p.expect('+')
-			typ = types.Typ[types.UntypedRune]
-			_, val = p.parseNumber()
-			p.expect(')')
-			break
-		}
-		_, re := p.parseNumber()
-		p.expect('+')
-		_, im := p.parseNumber()
-		p.expectKeyword("i")
-		p.expect(')')
-		typ = types.Typ[types.UntypedComplex]
-		val = constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
-
-	case scanner.Char:
-		// rune_lit
-		typ = types.Typ[types.UntypedRune]
-		val = constant.MakeFromLiteral(p.lit, token.CHAR, 0)
-		p.next()
-
-	case scanner.String:
-		// string_lit
-		typ = types.Typ[types.UntypedString]
-		val = constant.MakeFromLiteral(p.lit, token.STRING, 0)
-		p.next()
-
-	default:
-		p.errorf("expected literal got %s", scanner.TokenString(p.tok))
-	}
-
-	if typ0 == nil {
-		typ0 = typ
-	}
-
-	pkg.Scope().Insert(types.NewConst(token.NoPos, pkg, name, typ0, val))
-}
-
-// TypeDecl = "type" ExportedName Type .
-//
-func (p *parser) parseTypeDecl() {
-	p.expectKeyword("type")
-	pkg, name := p.parseExportedName()
-	obj := declTypeName(pkg, name)
-
-	// The type object may have been imported before and thus already
-	// have a type associated with it. We still need to parse the type
-	// structure, but throw it away if the object already has a type.
-	// This ensures that all imports refer to the same type object for
-	// a given type declaration.
-	typ := p.parseType(pkg)
-
-	if name := obj.Type().(*types.Named); name.Underlying() == nil {
-		name.SetUnderlying(typ)
-	}
-}
-
-// VarDecl = "var" ExportedName Type .
-//
-func (p *parser) parseVarDecl() {
-	p.expectKeyword("var")
-	pkg, name := p.parseExportedName()
-	typ := p.parseType(pkg)
-	pkg.Scope().Insert(types.NewVar(token.NoPos, pkg, name, typ))
-}
-
-// Func = Signature [ Body ] .
-// Body = "{" ... "}" .
-//
-func (p *parser) parseFunc(recv *types.Var) *types.Signature {
-	sig := p.parseSignature(recv)
-	if p.tok == '{' {
-		p.next()
-		for i := 1; i > 0; p.next() {
-			switch p.tok {
-			case '{':
-				i++
-			case '}':
-				i--
-			}
-		}
-	}
-	return sig
-}
-
-// MethodDecl = "func" Receiver Name Func .
-// Receiver   = "(" ( identifier | "?" ) [ "*" ] ExportedName ")" .
-//
-func (p *parser) parseMethodDecl() {
-	// "func" already consumed
-	p.expect('(')
-	recv, _ := p.parseParameter() // receiver
-	p.expect(')')
-
-	// determine receiver base type object
-	base := deref(recv.Type()).(*types.Named)
-
-	// parse method name, signature, and possibly inlined body
-	_, name := p.parseName(nil, false)
-	sig := p.parseFunc(recv)
-
-	// methods always belong to the same package as the base type object
-	pkg := base.Obj().Pkg()
-
-	// add method to type unless type was imported before
-	// and method exists already
-	// TODO(gri) This leads to a quadratic algorithm - ok for now because method counts are small.
-	base.AddMethod(types.NewFunc(token.NoPos, pkg, name, sig))
-}
-
-// FuncDecl = "func" ExportedName Func .
-//
-func (p *parser) parseFuncDecl() {
-	// "func" already consumed
-	pkg, name := p.parseExportedName()
-	typ := p.parseFunc(nil)
-	pkg.Scope().Insert(types.NewFunc(token.NoPos, pkg, name, typ))
-}
-
-// Decl = [ ImportDecl | ConstDecl | TypeDecl | VarDecl | FuncDecl | MethodDecl ] "\n" .
-//
-func (p *parser) parseDecl() {
-	if p.tok == scanner.Ident {
-		switch p.lit {
-		case "import":
-			p.parseImportDecl()
-		case "const":
-			p.parseConstDecl()
-		case "type":
-			p.parseTypeDecl()
-		case "var":
-			p.parseVarDecl()
-		case "func":
-			p.next() // look ahead
-			if p.tok == '(' {
-				p.parseMethodDecl()
-			} else {
-				p.parseFuncDecl()
-			}
-		}
-	}
-	p.expect('\n')
-}
-
-// ----------------------------------------------------------------------------
-// Export
-
-// Export        = "PackageClause { Decl } "$$" .
-// PackageClause = "package" PackageName [ "safe" ] "\n" .
-//
-func (p *parser) parseExport() *types.Package {
-	p.expectKeyword("package")
-	name := p.parsePackageName()
-	if p.tok == scanner.Ident && p.lit == "safe" {
-		// package was compiled with -u option - ignore
-		p.next()
-	}
-	p.expect('\n')
-
-	pkg := p.getPkg(p.id, name)
-
-	for p.tok != '$' && p.tok != scanner.EOF {
-		p.parseDecl()
-	}
-
-	if ch := p.scanner.Peek(); p.tok != '$' || ch != '$' {
-		// don't call next()/expect() since reading past the
-		// export data may cause scanner errors (e.g. NUL chars)
-		p.errorf("expected '$$', got %s %c", scanner.TokenString(p.tok), ch)
-	}
-
-	if n := p.scanner.ErrorCount; n != 0 {
-		p.errorf("expected no scanner errors, got %d", n)
-	}
-
-	// Record all locally referenced packages as imports.
-	var imports []*types.Package
-	for id, pkg2 := range p.localPkgs {
-		if pkg2.Name() == "" {
-			p.errorf("%s package has no name", id)
-		}
-		if id == p.id {
-			continue // avoid self-edge
-		}
-		imports = append(imports, pkg2)
-	}
-	sort.Sort(byPath(imports))
-	pkg.SetImports(imports)
-
-	// package was imported completely and without errors
-	pkg.MarkComplete()
-
-	return pkg
-}
-
-type byPath []*types.Package
-
-func (a byPath) Len() int           { return len(a) }
-func (a byPath) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-func (a byPath) Less(i, j int) bool { return a[i].Path() < a[j].Path() }
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go
deleted file mode 100644
index 4be32a2e55..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go
+++ /dev/null
@@ -1,739 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Indexed binary package export.
-// This file was derived from $GOROOT/src/cmd/compile/internal/gc/iexport.go;
-// see that file for specification of the format.
-
-package gcimporter
-
-import (
-	"bytes"
-	"encoding/binary"
-	"go/ast"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"io"
-	"math/big"
-	"reflect"
-	"sort"
-)
-
-// Current indexed export format version. Increase with each format change.
-// 0: Go1.11 encoding
-const iexportVersion = 0
-
-// IExportData returns the binary export data for pkg.
-//
-// If no file set is provided, position info will be missing.
-// The package path of the top-level package will not be recorded,
-// so that calls to IImportData can override with a provided package path.
-func IExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
-	defer func() {
-		if e := recover(); e != nil {
-			if ierr, ok := e.(internalError); ok {
-				err = ierr
-				return
-			}
-			// Not an internal error; panic again.
-			panic(e)
-		}
-	}()
-
-	p := iexporter{
-		out:         bytes.NewBuffer(nil),
-		fset:        fset,
-		allPkgs:     map[*types.Package]bool{},
-		stringIndex: map[string]uint64{},
-		declIndex:   map[types.Object]uint64{},
-		typIndex:    map[types.Type]uint64{},
-		localpkg:    pkg,
-	}
-
-	for i, pt := range predeclared() {
-		p.typIndex[pt] = uint64(i)
-	}
-	if len(p.typIndex) > predeclReserved {
-		panic(internalErrorf("too many predeclared types: %d > %d", len(p.typIndex), predeclReserved))
-	}
-
-	// Initialize work queue with exported declarations.
-	scope := pkg.Scope()
-	for _, name := range scope.Names() {
-		if ast.IsExported(name) {
-			p.pushDecl(scope.Lookup(name))
-		}
-	}
-
-	// Loop until no more work.
-	for !p.declTodo.empty() {
-		p.doDecl(p.declTodo.popHead())
-	}
-
-	// Append indices to data0 section.
-	dataLen := uint64(p.data0.Len())
-	w := p.newWriter()
-	w.writeIndex(p.declIndex)
-	w.flush()
-
-	// Assemble header.
-	var hdr intWriter
-	hdr.WriteByte('i')
-	hdr.uint64(iexportVersion)
-	hdr.uint64(uint64(p.strings.Len()))
-	hdr.uint64(dataLen)
-
-	// Flush output.
-	io.Copy(p.out, &hdr)
-	io.Copy(p.out, &p.strings)
-	io.Copy(p.out, &p.data0)
-
-	return p.out.Bytes(), nil
-}
-
-// writeIndex writes out an object index. mainIndex indicates whether
-// we're writing out the main index, which is also read by
-// non-compiler tools and includes a complete package description
-// (i.e., name and height).
-func (w *exportWriter) writeIndex(index map[types.Object]uint64) {
-	// Build a map from packages to objects from that package.
-	pkgObjs := map[*types.Package][]types.Object{}
-
-	// For the main index, make sure to include every package that
-	// we reference, even if we're not exporting (or reexporting)
-	// any symbols from it.
-	pkgObjs[w.p.localpkg] = nil
-	for pkg := range w.p.allPkgs {
-		pkgObjs[pkg] = nil
-	}
-
-	for obj := range index {
-		pkgObjs[obj.Pkg()] = append(pkgObjs[obj.Pkg()], obj)
-	}
-
-	var pkgs []*types.Package
-	for pkg, objs := range pkgObjs {
-		pkgs = append(pkgs, pkg)
-
-		sort.Slice(objs, func(i, j int) bool {
-			return objs[i].Name() < objs[j].Name()
-		})
-	}
-
-	sort.Slice(pkgs, func(i, j int) bool {
-		return w.exportPath(pkgs[i]) < w.exportPath(pkgs[j])
-	})
-
-	w.uint64(uint64(len(pkgs)))
-	for _, pkg := range pkgs {
-		w.string(w.exportPath(pkg))
-		w.string(pkg.Name())
-		w.uint64(uint64(0)) // package height is not needed for go/types
-
-		objs := pkgObjs[pkg]
-		w.uint64(uint64(len(objs)))
-		for _, obj := range objs {
-			w.string(obj.Name())
-			w.uint64(index[obj])
-		}
-	}
-}
-
-type iexporter struct {
-	fset *token.FileSet
-	out  *bytes.Buffer
-
-	localpkg *types.Package
-
-	// allPkgs tracks all packages that have been referenced by
-	// the export data, so we can ensure to include them in the
-	// main index.
-	allPkgs map[*types.Package]bool
-
-	declTodo objQueue
-
-	strings     intWriter
-	stringIndex map[string]uint64
-
-	data0     intWriter
-	declIndex map[types.Object]uint64
-	typIndex  map[types.Type]uint64
-}
-
-// stringOff returns the offset of s within the string section.
-// If not already present, it's added to the end.
-func (p *iexporter) stringOff(s string) uint64 {
-	off, ok := p.stringIndex[s]
-	if !ok {
-		off = uint64(p.strings.Len())
-		p.stringIndex[s] = off
-
-		p.strings.uint64(uint64(len(s)))
-		p.strings.WriteString(s)
-	}
-	return off
-}
-
-// pushDecl adds n to the declaration work queue, if not already present.
-func (p *iexporter) pushDecl(obj types.Object) {
-	// Package unsafe is known to the compiler and predeclared.
-	assert(obj.Pkg() != types.Unsafe)
-
-	if _, ok := p.declIndex[obj]; ok {
-		return
-	}
-
-	p.declIndex[obj] = ^uint64(0) // mark n present in work queue
-	p.declTodo.pushTail(obj)
-}
-
-// exportWriter handles writing out individual data section chunks.
-type exportWriter struct {
-	p *iexporter
-
-	data     intWriter
-	currPkg  *types.Package
-	prevFile string
-	prevLine int64
-}
-
-func (w *exportWriter) exportPath(pkg *types.Package) string {
-	if pkg == w.p.localpkg {
-		return ""
-	}
-	return pkg.Path()
-}
-
-func (p *iexporter) doDecl(obj types.Object) {
-	w := p.newWriter()
-	w.setPkg(obj.Pkg(), false)
-
-	switch obj := obj.(type) {
-	case *types.Var:
-		w.tag('V')
-		w.pos(obj.Pos())
-		w.typ(obj.Type(), obj.Pkg())
-
-	case *types.Func:
-		sig, _ := obj.Type().(*types.Signature)
-		if sig.Recv() != nil {
-			panic(internalErrorf("unexpected method: %v", sig))
-		}
-		w.tag('F')
-		w.pos(obj.Pos())
-		w.signature(sig)
-
-	case *types.Const:
-		w.tag('C')
-		w.pos(obj.Pos())
-		w.value(obj.Type(), obj.Val())
-
-	case *types.TypeName:
-		if obj.IsAlias() {
-			w.tag('A')
-			w.pos(obj.Pos())
-			w.typ(obj.Type(), obj.Pkg())
-			break
-		}
-
-		// Defined type.
-		w.tag('T')
-		w.pos(obj.Pos())
-
-		underlying := obj.Type().Underlying()
-		w.typ(underlying, obj.Pkg())
-
-		t := obj.Type()
-		if types.IsInterface(t) {
-			break
-		}
-
-		named, ok := t.(*types.Named)
-		if !ok {
-			panic(internalErrorf("%s is not a defined type", t))
-		}
-
-		n := named.NumMethods()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			m := named.Method(i)
-			w.pos(m.Pos())
-			w.string(m.Name())
-			sig, _ := m.Type().(*types.Signature)
-			w.param(sig.Recv())
-			w.signature(sig)
-		}
-
-	default:
-		panic(internalErrorf("unexpected object: %v", obj))
-	}
-
-	p.declIndex[obj] = w.flush()
-}
-
-func (w *exportWriter) tag(tag byte) {
-	w.data.WriteByte(tag)
-}
-
-func (w *exportWriter) pos(pos token.Pos) {
-	if w.p.fset == nil {
-		w.int64(0)
-		return
-	}
-
-	p := w.p.fset.Position(pos)
-	file := p.Filename
-	line := int64(p.Line)
-
-	// When file is the same as the last position (common case),
-	// we can save a few bytes by delta encoding just the line
-	// number.
-	//
-	// Note: Because data objects may be read out of order (or not
-	// at all), we can only apply delta encoding within a single
-	// object. This is handled implicitly by tracking prevFile and
-	// prevLine as fields of exportWriter.
-
-	if file == w.prevFile {
-		delta := line - w.prevLine
-		w.int64(delta)
-		if delta == deltaNewFile {
-			w.int64(-1)
-		}
-	} else {
-		w.int64(deltaNewFile)
-		w.int64(line) // line >= 0
-		w.string(file)
-		w.prevFile = file
-	}
-	w.prevLine = line
-}
-
-func (w *exportWriter) pkg(pkg *types.Package) {
-	// Ensure any referenced packages are declared in the main index.
-	w.p.allPkgs[pkg] = true
-
-	w.string(w.exportPath(pkg))
-}
-
-func (w *exportWriter) qualifiedIdent(obj types.Object) {
-	// Ensure any referenced declarations are written out too.
-	w.p.pushDecl(obj)
-
-	w.string(obj.Name())
-	w.pkg(obj.Pkg())
-}
-
-func (w *exportWriter) typ(t types.Type, pkg *types.Package) {
-	w.data.uint64(w.p.typOff(t, pkg))
-}
-
-func (p *iexporter) newWriter() *exportWriter {
-	return &exportWriter{p: p}
-}
-
-func (w *exportWriter) flush() uint64 {
-	off := uint64(w.p.data0.Len())
-	io.Copy(&w.p.data0, &w.data)
-	return off
-}
-
-func (p *iexporter) typOff(t types.Type, pkg *types.Package) uint64 {
-	off, ok := p.typIndex[t]
-	if !ok {
-		w := p.newWriter()
-		w.doTyp(t, pkg)
-		off = predeclReserved + w.flush()
-		p.typIndex[t] = off
-	}
-	return off
-}
-
-func (w *exportWriter) startType(k itag) {
-	w.data.uint64(uint64(k))
-}
-
-func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
-	switch t := t.(type) {
-	case *types.Named:
-		w.startType(definedType)
-		w.qualifiedIdent(t.Obj())
-
-	case *types.Pointer:
-		w.startType(pointerType)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Slice:
-		w.startType(sliceType)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Array:
-		w.startType(arrayType)
-		w.uint64(uint64(t.Len()))
-		w.typ(t.Elem(), pkg)
-
-	case *types.Chan:
-		w.startType(chanType)
-		// 1 RecvOnly; 2 SendOnly; 3 SendRecv
-		var dir uint64
-		switch t.Dir() {
-		case types.RecvOnly:
-			dir = 1
-		case types.SendOnly:
-			dir = 2
-		case types.SendRecv:
-			dir = 3
-		}
-		w.uint64(dir)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Map:
-		w.startType(mapType)
-		w.typ(t.Key(), pkg)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Signature:
-		w.startType(signatureType)
-		w.setPkg(pkg, true)
-		w.signature(t)
-
-	case *types.Struct:
-		w.startType(structType)
-		w.setPkg(pkg, true)
-
-		n := t.NumFields()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			f := t.Field(i)
-			w.pos(f.Pos())
-			w.string(f.Name())
-			w.typ(f.Type(), pkg)
-			w.bool(f.Anonymous())
-			w.string(t.Tag(i)) // note (or tag)
-		}
-
-	case *types.Interface:
-		w.startType(interfaceType)
-		w.setPkg(pkg, true)
-
-		n := t.NumEmbeddeds()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			f := t.Embedded(i)
-			w.pos(f.Obj().Pos())
-			w.typ(f.Obj().Type(), f.Obj().Pkg())
-		}
-
-		n = t.NumExplicitMethods()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			m := t.ExplicitMethod(i)
-			w.pos(m.Pos())
-			w.string(m.Name())
-			sig, _ := m.Type().(*types.Signature)
-			w.signature(sig)
-		}
-
-	default:
-		panic(internalErrorf("unexpected type: %v, %v", t, reflect.TypeOf(t)))
-	}
-}
-
-func (w *exportWriter) setPkg(pkg *types.Package, write bool) {
-	if write {
-		w.pkg(pkg)
-	}
-
-	w.currPkg = pkg
-}
-
-func (w *exportWriter) signature(sig *types.Signature) {
-	w.paramList(sig.Params())
-	w.paramList(sig.Results())
-	if sig.Params().Len() > 0 {
-		w.bool(sig.Variadic())
-	}
-}
-
-func (w *exportWriter) paramList(tup *types.Tuple) {
-	n := tup.Len()
-	w.uint64(uint64(n))
-	for i := 0; i < n; i++ {
-		w.param(tup.At(i))
-	}
-}
-
-func (w *exportWriter) param(obj types.Object) {
-	w.pos(obj.Pos())
-	w.localIdent(obj)
-	w.typ(obj.Type(), obj.Pkg())
-}
-
-func (w *exportWriter) value(typ types.Type, v constant.Value) {
-	w.typ(typ, nil)
-
-	switch v.Kind() {
-	case constant.Bool:
-		w.bool(constant.BoolVal(v))
-	case constant.Int:
-		var i big.Int
-		if i64, exact := constant.Int64Val(v); exact {
-			i.SetInt64(i64)
-		} else if ui64, exact := constant.Uint64Val(v); exact {
-			i.SetUint64(ui64)
-		} else {
-			i.SetString(v.ExactString(), 10)
-		}
-		w.mpint(&i, typ)
-	case constant.Float:
-		f := constantToFloat(v)
-		w.mpfloat(f, typ)
-	case constant.Complex:
-		w.mpfloat(constantToFloat(constant.Real(v)), typ)
-		w.mpfloat(constantToFloat(constant.Imag(v)), typ)
-	case constant.String:
-		w.string(constant.StringVal(v))
-	case constant.Unknown:
-		// package contains type errors
-	default:
-		panic(internalErrorf("unexpected value %v (%T)", v, v))
-	}
-}
-
-// constantToFloat converts a constant.Value with kind constant.Float to a
-// big.Float.
-func constantToFloat(x constant.Value) *big.Float {
-	assert(x.Kind() == constant.Float)
-	// Use the same floating-point precision (512) as cmd/compile
-	// (see Mpprec in cmd/compile/internal/gc/mpfloat.go).
-	const mpprec = 512
-	var f big.Float
-	f.SetPrec(mpprec)
-	if v, exact := constant.Float64Val(x); exact {
-		// float64
-		f.SetFloat64(v)
-	} else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
-		// TODO(gri): add big.Rat accessor to constant.Value.
-		n := valueToRat(num)
-		d := valueToRat(denom)
-		f.SetRat(n.Quo(n, d))
-	} else {
-		// Value too large to represent as a fraction => inaccessible.
-		// TODO(gri): add big.Float accessor to constant.Value.
-		_, ok := f.SetString(x.ExactString())
-		assert(ok)
-	}
-	return &f
-}
-
-// mpint exports a multi-precision integer.
-//
-// For unsigned types, small values are written out as a single
-// byte. Larger values are written out as a length-prefixed big-endian
-// byte string, where the length prefix is encoded as its complement.
-// For example, bytes 0, 1, and 2 directly represent the integer
-// values 0, 1, and 2; while bytes 255, 254, and 253 indicate a 1-,
-// 2-, and 3-byte big-endian string follow.
-//
-// Encoding for signed types use the same general approach as for
-// unsigned types, except small values use zig-zag encoding and the
-// bottom bit of length prefix byte for large values is reserved as a
-// sign bit.
-//
-// The exact boundary between small and large encodings varies
-// according to the maximum number of bytes needed to encode a value
-// of type typ. As a special case, 8-bit types are always encoded as a
-// single byte.
-//
-// TODO(mdempsky): Is this level of complexity really worthwhile?
-func (w *exportWriter) mpint(x *big.Int, typ types.Type) {
-	basic, ok := typ.Underlying().(*types.Basic)
-	if !ok {
-		panic(internalErrorf("unexpected type %v (%T)", typ.Underlying(), typ.Underlying()))
-	}
-
-	signed, maxBytes := intSize(basic)
-
-	negative := x.Sign() < 0
-	if !signed && negative {
-		panic(internalErrorf("negative unsigned integer; type %v, value %v", typ, x))
-	}
-
-	b := x.Bytes()
-	if len(b) > 0 && b[0] == 0 {
-		panic(internalErrorf("leading zeros"))
-	}
-	if uint(len(b)) > maxBytes {
-		panic(internalErrorf("bad mpint length: %d > %d (type %v, value %v)", len(b), maxBytes, typ, x))
-	}
-
-	maxSmall := 256 - maxBytes
-	if signed {
-		maxSmall = 256 - 2*maxBytes
-	}
-	if maxBytes == 1 {
-		maxSmall = 256
-	}
-
-	// Check if x can use small value encoding.
-	if len(b) <= 1 {
-		var ux uint
-		if len(b) == 1 {
-			ux = uint(b[0])
-		}
-		if signed {
-			ux <<= 1
-			if negative {
-				ux--
-			}
-		}
-		if ux < maxSmall {
-			w.data.WriteByte(byte(ux))
-			return
-		}
-	}
-
-	n := 256 - uint(len(b))
-	if signed {
-		n = 256 - 2*uint(len(b))
-		if negative {
-			n |= 1
-		}
-	}
-	if n < maxSmall || n >= 256 {
-		panic(internalErrorf("encoding mistake: %d, %v, %v => %d", len(b), signed, negative, n))
-	}
-
-	w.data.WriteByte(byte(n))
-	w.data.Write(b)
-}
-
-// mpfloat exports a multi-precision floating point number.
-//
-// The number's value is decomposed into mantissa × 2**exponent, where
-// mantissa is an integer. The value is written out as mantissa (as a
-// multi-precision integer) and then the exponent, except exponent is
-// omitted if mantissa is zero.
-func (w *exportWriter) mpfloat(f *big.Float, typ types.Type) {
-	if f.IsInf() {
-		panic("infinite constant")
-	}
-
-	// Break into f = mant × 2**exp, with 0.5 <= mant < 1.
-	var mant big.Float
-	exp := int64(f.MantExp(&mant))
-
-	// Scale so that mant is an integer.
-	prec := mant.MinPrec()
-	mant.SetMantExp(&mant, int(prec))
-	exp -= int64(prec)
-
-	manti, acc := mant.Int(nil)
-	if acc != big.Exact {
-		panic(internalErrorf("mantissa scaling failed for %f (%s)", f, acc))
-	}
-	w.mpint(manti, typ)
-	if manti.Sign() != 0 {
-		w.int64(exp)
-	}
-}
-
-func (w *exportWriter) bool(b bool) bool {
-	var x uint64
-	if b {
-		x = 1
-	}
-	w.uint64(x)
-	return b
-}
-
-func (w *exportWriter) int64(x int64)   { w.data.int64(x) }
-func (w *exportWriter) uint64(x uint64) { w.data.uint64(x) }
-func (w *exportWriter) string(s string) { w.uint64(w.p.stringOff(s)) }
-
-func (w *exportWriter) localIdent(obj types.Object) {
-	// Anonymous parameters.
-	if obj == nil {
-		w.string("")
-		return
-	}
-
-	name := obj.Name()
-	if name == "_" {
-		w.string("_")
-		return
-	}
-
-	w.string(name)
-}
-
-type intWriter struct {
-	bytes.Buffer
-}
-
-func (w *intWriter) int64(x int64) {
-	var buf [binary.MaxVarintLen64]byte
-	n := binary.PutVarint(buf[:], x)
-	w.Write(buf[:n])
-}
-
-func (w *intWriter) uint64(x uint64) {
-	var buf [binary.MaxVarintLen64]byte
-	n := binary.PutUvarint(buf[:], x)
-	w.Write(buf[:n])
-}
-
-func assert(cond bool) {
-	if !cond {
-		panic("internal error: assertion failed")
-	}
-}
-
-// The below is copied from go/src/cmd/compile/internal/gc/syntax.go.
-
-// objQueue is a FIFO queue of types.Object. The zero value of objQueue is
-// a ready-to-use empty queue.
-type objQueue struct {
-	ring       []types.Object
-	head, tail int
-}
-
-// empty returns true if q contains no Nodes.
-func (q *objQueue) empty() bool {
-	return q.head == q.tail
-}
-
-// pushTail appends n to the tail of the queue.
-func (q *objQueue) pushTail(obj types.Object) {
-	if len(q.ring) == 0 {
-		q.ring = make([]types.Object, 16)
-	} else if q.head+len(q.ring) == q.tail {
-		// Grow the ring.
-		nring := make([]types.Object, len(q.ring)*2)
-		// Copy the old elements.
-		part := q.ring[q.head%len(q.ring):]
-		if q.tail-q.head <= len(part) {
-			part = part[:q.tail-q.head]
-			copy(nring, part)
-		} else {
-			pos := copy(nring, part)
-			copy(nring[pos:], q.ring[:q.tail%len(q.ring)])
-		}
-		q.ring, q.head, q.tail = nring, 0, q.tail-q.head
-	}
-
-	q.ring[q.tail%len(q.ring)] = obj
-	q.tail++
-}
-
-// popHead pops a node from the head of the queue. It panics if q is empty.
-func (q *objQueue) popHead() types.Object {
-	if q.empty() {
-		panic("dequeue empty")
-	}
-	obj := q.ring[q.head%len(q.ring)]
-	q.head++
-	return obj
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go
deleted file mode 100644
index a31a880263..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go
+++ /dev/null
@@ -1,630 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Indexed package import.
-// See cmd/compile/internal/gc/iexport.go for the export data format.
-
-// This file is a copy of $GOROOT/src/go/internal/gcimporter/iimport.go.
-
-package gcimporter
-
-import (
-	"bytes"
-	"encoding/binary"
-	"fmt"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"io"
-	"sort"
-)
-
-type intReader struct {
-	*bytes.Reader
-	path string
-}
-
-func (r *intReader) int64() int64 {
-	i, err := binary.ReadVarint(r.Reader)
-	if err != nil {
-		errorf("import %q: read varint error: %v", r.path, err)
-	}
-	return i
-}
-
-func (r *intReader) uint64() uint64 {
-	i, err := binary.ReadUvarint(r.Reader)
-	if err != nil {
-		errorf("import %q: read varint error: %v", r.path, err)
-	}
-	return i
-}
-
-const predeclReserved = 32
-
-type itag uint64
-
-const (
-	// Types
-	definedType itag = iota
-	pointerType
-	sliceType
-	arrayType
-	chanType
-	mapType
-	signatureType
-	structType
-	interfaceType
-)
-
-// IImportData imports a package from the serialized package data
-// and returns the number of bytes consumed and a reference to the package.
-// If the export data version is not recognized or the format is otherwise
-// compromised, an error is returned.
-func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (_ int, pkg *types.Package, err error) {
-	const currentVersion = 1
-	version := int64(-1)
-	defer func() {
-		if e := recover(); e != nil {
-			if version > currentVersion {
-				err = fmt.Errorf("cannot import %q (%v), export data is newer version - update tool", path, e)
-			} else {
-				err = fmt.Errorf("cannot import %q (%v), possibly version skew - reinstall package", path, e)
-			}
-		}
-	}()
-
-	r := &intReader{bytes.NewReader(data), path}
-
-	version = int64(r.uint64())
-	switch version {
-	case currentVersion, 0:
-	default:
-		errorf("unknown iexport format version %d", version)
-	}
-
-	sLen := int64(r.uint64())
-	dLen := int64(r.uint64())
-
-	whence, _ := r.Seek(0, io.SeekCurrent)
-	stringData := data[whence : whence+sLen]
-	declData := data[whence+sLen : whence+sLen+dLen]
-	r.Seek(sLen+dLen, io.SeekCurrent)
-
-	p := iimporter{
-		ipath:   path,
-		version: int(version),
-
-		stringData:  stringData,
-		stringCache: make(map[uint64]string),
-		pkgCache:    make(map[uint64]*types.Package),
-
-		declData: declData,
-		pkgIndex: make(map[*types.Package]map[string]uint64),
-		typCache: make(map[uint64]types.Type),
-
-		fake: fakeFileSet{
-			fset:  fset,
-			files: make(map[string]*token.File),
-		},
-	}
-
-	for i, pt := range predeclared() {
-		p.typCache[uint64(i)] = pt
-	}
-
-	pkgList := make([]*types.Package, r.uint64())
-	for i := range pkgList {
-		pkgPathOff := r.uint64()
-		pkgPath := p.stringAt(pkgPathOff)
-		pkgName := p.stringAt(r.uint64())
-		_ = r.uint64() // package height; unused by go/types
-
-		if pkgPath == "" {
-			pkgPath = path
-		}
-		pkg := imports[pkgPath]
-		if pkg == nil {
-			pkg = types.NewPackage(pkgPath, pkgName)
-			imports[pkgPath] = pkg
-		} else if pkg.Name() != pkgName {
-			errorf("conflicting names %s and %s for package %q", pkg.Name(), pkgName, path)
-		}
-
-		p.pkgCache[pkgPathOff] = pkg
-
-		nameIndex := make(map[string]uint64)
-		for nSyms := r.uint64(); nSyms > 0; nSyms-- {
-			name := p.stringAt(r.uint64())
-			nameIndex[name] = r.uint64()
-		}
-
-		p.pkgIndex[pkg] = nameIndex
-		pkgList[i] = pkg
-	}
-	if len(pkgList) == 0 {
-		errorf("no packages found for %s", path)
-		panic("unreachable")
-	}
-	p.ipkg = pkgList[0]
-	names := make([]string, 0, len(p.pkgIndex[p.ipkg]))
-	for name := range p.pkgIndex[p.ipkg] {
-		names = append(names, name)
-	}
-	sort.Strings(names)
-	for _, name := range names {
-		p.doDecl(p.ipkg, name)
-	}
-
-	for _, typ := range p.interfaceList {
-		typ.Complete()
-	}
-
-	// record all referenced packages as imports
-	list := append(([]*types.Package)(nil), pkgList[1:]...)
-	sort.Sort(byPath(list))
-	p.ipkg.SetImports(list)
-
-	// package was imported completely and without errors
-	p.ipkg.MarkComplete()
-
-	consumed, _ := r.Seek(0, io.SeekCurrent)
-	return int(consumed), p.ipkg, nil
-}
-
-type iimporter struct {
-	ipath   string
-	ipkg    *types.Package
-	version int
-
-	stringData  []byte
-	stringCache map[uint64]string
-	pkgCache    map[uint64]*types.Package
-
-	declData []byte
-	pkgIndex map[*types.Package]map[string]uint64
-	typCache map[uint64]types.Type
-
-	fake          fakeFileSet
-	interfaceList []*types.Interface
-}
-
-func (p *iimporter) doDecl(pkg *types.Package, name string) {
-	// See if we've already imported this declaration.
-	if obj := pkg.Scope().Lookup(name); obj != nil {
-		return
-	}
-
-	off, ok := p.pkgIndex[pkg][name]
-	if !ok {
-		errorf("%v.%v not in index", pkg, name)
-	}
-
-	r := &importReader{p: p, currPkg: pkg}
-	r.declReader.Reset(p.declData[off:])
-
-	r.obj(name)
-}
-
-func (p *iimporter) stringAt(off uint64) string {
-	if s, ok := p.stringCache[off]; ok {
-		return s
-	}
-
-	slen, n := binary.Uvarint(p.stringData[off:])
-	if n <= 0 {
-		errorf("varint failed")
-	}
-	spos := off + uint64(n)
-	s := string(p.stringData[spos : spos+slen])
-	p.stringCache[off] = s
-	return s
-}
-
-func (p *iimporter) pkgAt(off uint64) *types.Package {
-	if pkg, ok := p.pkgCache[off]; ok {
-		return pkg
-	}
-	path := p.stringAt(off)
-	if path == p.ipath {
-		return p.ipkg
-	}
-	errorf("missing package %q in %q", path, p.ipath)
-	return nil
-}
-
-func (p *iimporter) typAt(off uint64, base *types.Named) types.Type {
-	if t, ok := p.typCache[off]; ok && (base == nil || !isInterface(t)) {
-		return t
-	}
-
-	if off < predeclReserved {
-		errorf("predeclared type missing from cache: %v", off)
-	}
-
-	r := &importReader{p: p}
-	r.declReader.Reset(p.declData[off-predeclReserved:])
-	t := r.doType(base)
-
-	if base == nil || !isInterface(t) {
-		p.typCache[off] = t
-	}
-	return t
-}
-
-type importReader struct {
-	p          *iimporter
-	declReader bytes.Reader
-	currPkg    *types.Package
-	prevFile   string
-	prevLine   int64
-	prevColumn int64
-}
-
-func (r *importReader) obj(name string) {
-	tag := r.byte()
-	pos := r.pos()
-
-	switch tag {
-	case 'A':
-		typ := r.typ()
-
-		r.declare(types.NewTypeName(pos, r.currPkg, name, typ))
-
-	case 'C':
-		typ, val := r.value()
-
-		r.declare(types.NewConst(pos, r.currPkg, name, typ, val))
-
-	case 'F':
-		sig := r.signature(nil)
-
-		r.declare(types.NewFunc(pos, r.currPkg, name, sig))
-
-	case 'T':
-		// Types can be recursive. We need to setup a stub
-		// declaration before recursing.
-		obj := types.NewTypeName(pos, r.currPkg, name, nil)
-		named := types.NewNamed(obj, nil, nil)
-		r.declare(obj)
-
-		underlying := r.p.typAt(r.uint64(), named).Underlying()
-		named.SetUnderlying(underlying)
-
-		if !isInterface(underlying) {
-			for n := r.uint64(); n > 0; n-- {
-				mpos := r.pos()
-				mname := r.ident()
-				recv := r.param()
-				msig := r.signature(recv)
-
-				named.AddMethod(types.NewFunc(mpos, r.currPkg, mname, msig))
-			}
-		}
-
-	case 'V':
-		typ := r.typ()
-
-		r.declare(types.NewVar(pos, r.currPkg, name, typ))
-
-	default:
-		errorf("unexpected tag: %v", tag)
-	}
-}
-
-func (r *importReader) declare(obj types.Object) {
-	obj.Pkg().Scope().Insert(obj)
-}
-
-func (r *importReader) value() (typ types.Type, val constant.Value) {
-	typ = r.typ()
-
-	switch b := typ.Underlying().(*types.Basic); b.Info() & types.IsConstType {
-	case types.IsBoolean:
-		val = constant.MakeBool(r.bool())
-
-	case types.IsString:
-		val = constant.MakeString(r.string())
-
-	case types.IsInteger:
-		val = r.mpint(b)
-
-	case types.IsFloat:
-		val = r.mpfloat(b)
-
-	case types.IsComplex:
-		re := r.mpfloat(b)
-		im := r.mpfloat(b)
-		val = constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
-
-	default:
-		if b.Kind() == types.Invalid {
-			val = constant.MakeUnknown()
-			return
-		}
-		errorf("unexpected type %v", typ) // panics
-		panic("unreachable")
-	}
-
-	return
-}
-
-func intSize(b *types.Basic) (signed bool, maxBytes uint) {
-	if (b.Info() & types.IsUntyped) != 0 {
-		return true, 64
-	}
-
-	switch b.Kind() {
-	case types.Float32, types.Complex64:
-		return true, 3
-	case types.Float64, types.Complex128:
-		return true, 7
-	}
-
-	signed = (b.Info() & types.IsUnsigned) == 0
-	switch b.Kind() {
-	case types.Int8, types.Uint8:
-		maxBytes = 1
-	case types.Int16, types.Uint16:
-		maxBytes = 2
-	case types.Int32, types.Uint32:
-		maxBytes = 4
-	default:
-		maxBytes = 8
-	}
-
-	return
-}
-
-func (r *importReader) mpint(b *types.Basic) constant.Value {
-	signed, maxBytes := intSize(b)
-
-	maxSmall := 256 - maxBytes
-	if signed {
-		maxSmall = 256 - 2*maxBytes
-	}
-	if maxBytes == 1 {
-		maxSmall = 256
-	}
-
-	n, _ := r.declReader.ReadByte()
-	if uint(n) < maxSmall {
-		v := int64(n)
-		if signed {
-			v >>= 1
-			if n&1 != 0 {
-				v = ^v
-			}
-		}
-		return constant.MakeInt64(v)
-	}
-
-	v := -n
-	if signed {
-		v = -(n &^ 1) >> 1
-	}
-	if v < 1 || uint(v) > maxBytes {
-		errorf("weird decoding: %v, %v => %v", n, signed, v)
-	}
-
-	buf := make([]byte, v)
-	io.ReadFull(&r.declReader, buf)
-
-	// convert to little endian
-	// TODO(gri) go/constant should have a more direct conversion function
-	//           (e.g., once it supports a big.Float based implementation)
-	for i, j := 0, len(buf)-1; i < j; i, j = i+1, j-1 {
-		buf[i], buf[j] = buf[j], buf[i]
-	}
-
-	x := constant.MakeFromBytes(buf)
-	if signed && n&1 != 0 {
-		x = constant.UnaryOp(token.SUB, x, 0)
-	}
-	return x
-}
-
-func (r *importReader) mpfloat(b *types.Basic) constant.Value {
-	x := r.mpint(b)
-	if constant.Sign(x) == 0 {
-		return x
-	}
-
-	exp := r.int64()
-	switch {
-	case exp > 0:
-		x = constant.Shift(x, token.SHL, uint(exp))
-	case exp < 0:
-		d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp))
-		x = constant.BinaryOp(x, token.QUO, d)
-	}
-	return x
-}
-
-func (r *importReader) ident() string {
-	return r.string()
-}
-
-func (r *importReader) qualifiedIdent() (*types.Package, string) {
-	name := r.string()
-	pkg := r.pkg()
-	return pkg, name
-}
-
-func (r *importReader) pos() token.Pos {
-	if r.p.version >= 1 {
-		r.posv1()
-	} else {
-		r.posv0()
-	}
-
-	if r.prevFile == "" && r.prevLine == 0 && r.prevColumn == 0 {
-		return token.NoPos
-	}
-	return r.p.fake.pos(r.prevFile, int(r.prevLine), int(r.prevColumn))
-}
-
-func (r *importReader) posv0() {
-	delta := r.int64()
-	if delta != deltaNewFile {
-		r.prevLine += delta
-	} else if l := r.int64(); l == -1 {
-		r.prevLine += deltaNewFile
-	} else {
-		r.prevFile = r.string()
-		r.prevLine = l
-	}
-}
-
-func (r *importReader) posv1() {
-	delta := r.int64()
-	r.prevColumn += delta >> 1
-	if delta&1 != 0 {
-		delta = r.int64()
-		r.prevLine += delta >> 1
-		if delta&1 != 0 {
-			r.prevFile = r.string()
-		}
-	}
-}
-
-func (r *importReader) typ() types.Type {
-	return r.p.typAt(r.uint64(), nil)
-}
-
-func isInterface(t types.Type) bool {
-	_, ok := t.(*types.Interface)
-	return ok
-}
-
-func (r *importReader) pkg() *types.Package { return r.p.pkgAt(r.uint64()) }
-func (r *importReader) string() string      { return r.p.stringAt(r.uint64()) }
-
-func (r *importReader) doType(base *types.Named) types.Type {
-	switch k := r.kind(); k {
-	default:
-		errorf("unexpected kind tag in %q: %v", r.p.ipath, k)
-		return nil
-
-	case definedType:
-		pkg, name := r.qualifiedIdent()
-		r.p.doDecl(pkg, name)
-		return pkg.Scope().Lookup(name).(*types.TypeName).Type()
-	case pointerType:
-		return types.NewPointer(r.typ())
-	case sliceType:
-		return types.NewSlice(r.typ())
-	case arrayType:
-		n := r.uint64()
-		return types.NewArray(r.typ(), int64(n))
-	case chanType:
-		dir := chanDir(int(r.uint64()))
-		return types.NewChan(dir, r.typ())
-	case mapType:
-		return types.NewMap(r.typ(), r.typ())
-	case signatureType:
-		r.currPkg = r.pkg()
-		return r.signature(nil)
-
-	case structType:
-		r.currPkg = r.pkg()
-
-		fields := make([]*types.Var, r.uint64())
-		tags := make([]string, len(fields))
-		for i := range fields {
-			fpos := r.pos()
-			fname := r.ident()
-			ftyp := r.typ()
-			emb := r.bool()
-			tag := r.string()
-
-			fields[i] = types.NewField(fpos, r.currPkg, fname, ftyp, emb)
-			tags[i] = tag
-		}
-		return types.NewStruct(fields, tags)
-
-	case interfaceType:
-		r.currPkg = r.pkg()
-
-		embeddeds := make([]types.Type, r.uint64())
-		for i := range embeddeds {
-			_ = r.pos()
-			embeddeds[i] = r.typ()
-		}
-
-		methods := make([]*types.Func, r.uint64())
-		for i := range methods {
-			mpos := r.pos()
-			mname := r.ident()
-
-			// TODO(mdempsky): Matches bimport.go, but I
-			// don't agree with this.
-			var recv *types.Var
-			if base != nil {
-				recv = types.NewVar(token.NoPos, r.currPkg, "", base)
-			}
-
-			msig := r.signature(recv)
-			methods[i] = types.NewFunc(mpos, r.currPkg, mname, msig)
-		}
-
-		typ := newInterface(methods, embeddeds)
-		r.p.interfaceList = append(r.p.interfaceList, typ)
-		return typ
-	}
-}
-
-func (r *importReader) kind() itag {
-	return itag(r.uint64())
-}
-
-func (r *importReader) signature(recv *types.Var) *types.Signature {
-	params := r.paramList()
-	results := r.paramList()
-	variadic := params.Len() > 0 && r.bool()
-	return types.NewSignature(recv, params, results, variadic)
-}
-
-func (r *importReader) paramList() *types.Tuple {
-	xs := make([]*types.Var, r.uint64())
-	for i := range xs {
-		xs[i] = r.param()
-	}
-	return types.NewTuple(xs...)
-}
-
-func (r *importReader) param() *types.Var {
-	pos := r.pos()
-	name := r.ident()
-	typ := r.typ()
-	return types.NewParam(pos, r.currPkg, name, typ)
-}
-
-func (r *importReader) bool() bool {
-	return r.uint64() != 0
-}
-
-func (r *importReader) int64() int64 {
-	n, err := binary.ReadVarint(&r.declReader)
-	if err != nil {
-		errorf("readVarint: %v", err)
-	}
-	return n
-}
-
-func (r *importReader) uint64() uint64 {
-	n, err := binary.ReadUvarint(&r.declReader)
-	if err != nil {
-		errorf("readUvarint: %v", err)
-	}
-	return n
-}
-
-func (r *importReader) byte() byte {
-	x, err := r.declReader.ReadByte()
-	if err != nil {
-		errorf("declReader.ReadByte: %v", err)
-	}
-	return x
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface10.go b/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface10.go
deleted file mode 100644
index 463f252271..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface10.go
+++ /dev/null
@@ -1,21 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build !go1.11
-
-package gcimporter
-
-import "go/types"
-
-func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
-	named := make([]*types.Named, len(embeddeds))
-	for i, e := range embeddeds {
-		var ok bool
-		named[i], ok = e.(*types.Named)
-		if !ok {
-			panic("embedding of non-defined interfaces in interfaces is not supported before Go 1.11")
-		}
-	}
-	return types.NewInterface(methods, named)
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface11.go b/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface11.go
deleted file mode 100644
index ab28b95cbb..0000000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface11.go
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build go1.11
-
-package gcimporter
-
-import "go/types"
-
-func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
-	return types.NewInterfaceType(methods, embeddeds)
-}
diff --git a/vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go b/vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go
deleted file mode 100644
index f4d73b2339..0000000000
--- a/vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package packagesdriver fetches type sizes for go/packages and go/analysis.
-package packagesdriver
-
-import (
-	"context"
-	"fmt"
-	"go/types"
-	"strings"
-
-	"golang.org/x/tools/internal/gocommand"
-)
-
-var debug = false
-
-func GetSizesGolist(ctx context.Context, inv gocommand.Invocation, gocmdRunner *gocommand.Runner) (types.Sizes, error) {
-	inv.Verb = "list"
-	inv.Args = []string{"-f", "{{context.GOARCH}} {{context.Compiler}}", "--", "unsafe"}
-	stdout, stderr, friendlyErr, rawErr := gocmdRunner.RunRaw(ctx, inv)
-	var goarch, compiler string
-	if rawErr != nil {
-		if strings.Contains(rawErr.Error(), "cannot find main module") {
-			// User's running outside of a module. All bets are off. Get GOARCH and guess compiler is gc.
-			// TODO(matloob): Is this a problem in practice?
-			inv.Verb = "env"
-			inv.Args = []string{"GOARCH"}
-			envout, enverr := gocmdRunner.Run(ctx, inv)
-			if enverr != nil {
-				return nil, enverr
-			}
-			goarch = strings.TrimSpace(envout.String())
-			compiler = "gc"
-		} else {
-			return nil, friendlyErr
-		}
-	} else {
-		fields := strings.Fields(stdout.String())
-		if len(fields) < 2 {
-			return nil, fmt.Errorf("could not parse GOARCH and Go compiler in format \"<GOARCH> <compiler>\":\nstdout: <<%s>>\nstderr: <<%s>>",
-				stdout.String(), stderr.String())
-		}
-		goarch = fields[0]
-		compiler = fields[1]
-	}
-	return types.SizesFor(compiler, goarch), nil
-}
diff --git a/vendor/golang.org/x/tools/go/loader/doc.go b/vendor/golang.org/x/tools/go/loader/doc.go
deleted file mode 100644
index c5aa31c1a0..0000000000
--- a/vendor/golang.org/x/tools/go/loader/doc.go
+++ /dev/null
@@ -1,204 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package loader loads a complete Go program from source code, parsing
-// and type-checking the initial packages plus their transitive closure
-// of dependencies.  The ASTs and the derived facts are retained for
-// later use.
-//
-// Deprecated: This is an older API and does not have support
-// for modules. Use golang.org/x/tools/go/packages instead.
-//
-// The package defines two primary types: Config, which specifies a
-// set of initial packages to load and various other options; and
-// Program, which is the result of successfully loading the packages
-// specified by a configuration.
-//
-// The configuration can be set directly, but *Config provides various
-// convenience methods to simplify the common cases, each of which can
-// be called any number of times.  Finally, these are followed by a
-// call to Load() to actually load and type-check the program.
-//
-//      var conf loader.Config
-//
-//      // Use the command-line arguments to specify
-//      // a set of initial packages to load from source.
-//      // See FromArgsUsage for help.
-//      rest, err := conf.FromArgs(os.Args[1:], wantTests)
-//
-//      // Parse the specified files and create an ad hoc package with path "foo".
-//      // All files must have the same 'package' declaration.
-//      conf.CreateFromFilenames("foo", "foo.go", "bar.go")
-//
-//      // Create an ad hoc package with path "foo" from
-//      // the specified already-parsed files.
-//      // All ASTs must have the same 'package' declaration.
-//      conf.CreateFromFiles("foo", parsedFiles)
-//
-//      // Add "runtime" to the set of packages to be loaded.
-//      conf.Import("runtime")
-//
-//      // Adds "fmt" and "fmt_test" to the set of packages
-//      // to be loaded.  "fmt" will include *_test.go files.
-//      conf.ImportWithTests("fmt")
-//
-//      // Finally, load all the packages specified by the configuration.
-//      prog, err := conf.Load()
-//
-// See examples_test.go for examples of API usage.
-//
-//
-// CONCEPTS AND TERMINOLOGY
-//
-// The WORKSPACE is the set of packages accessible to the loader.  The
-// workspace is defined by Config.Build, a *build.Context.  The
-// default context treats subdirectories of $GOROOT and $GOPATH as
-// packages, but this behavior may be overridden.
-//
-// An AD HOC package is one specified as a set of source files on the
-// command line.  In the simplest case, it may consist of a single file
-// such as $GOROOT/src/net/http/triv.go.
-//
-// EXTERNAL TEST packages are those comprised of a set of *_test.go
-// files all with the same 'package foo_test' declaration, all in the
-// same directory.  (go/build.Package calls these files XTestFiles.)
-//
-// An IMPORTABLE package is one that can be referred to by some import
-// spec.  Every importable package is uniquely identified by its
-// PACKAGE PATH or just PATH, a string such as "fmt", "encoding/json",
-// or "cmd/vendor/golang.org/x/arch/x86/x86asm".  A package path
-// typically denotes a subdirectory of the workspace.
-//
-// An import declaration uses an IMPORT PATH to refer to a package.
-// Most import declarations use the package path as the import path.
-//
-// Due to VENDORING (https://golang.org/s/go15vendor), the
-// interpretation of an import path may depend on the directory in which
-// it appears.  To resolve an import path to a package path, go/build
-// must search the enclosing directories for a subdirectory named
-// "vendor".
-//
-// ad hoc packages and external test packages are NON-IMPORTABLE.  The
-// path of an ad hoc package is inferred from the package
-// declarations of its files and is therefore not a unique package key.
-// For example, Config.CreatePkgs may specify two initial ad hoc
-// packages, both with path "main".
-//
-// An AUGMENTED package is an importable package P plus all the
-// *_test.go files with same 'package foo' declaration as P.
-// (go/build.Package calls these files TestFiles.)
-//
-// The INITIAL packages are those specified in the configuration.  A
-// DEPENDENCY is a package loaded to satisfy an import in an initial
-// package or another dependency.
-//
-package loader
-
-// IMPLEMENTATION NOTES
-//
-// 'go test', in-package test files, and import cycles
-// ---------------------------------------------------
-//
-// An external test package may depend upon members of the augmented
-// package that are not in the unaugmented package, such as functions
-// that expose internals.  (See bufio/export_test.go for an example.)
-// So, the loader must ensure that for each external test package
-// it loads, it also augments the corresponding non-test package.
-//
-// The import graph over n unaugmented packages must be acyclic; the
-// import graph over n-1 unaugmented packages plus one augmented
-// package must also be acyclic.  ('go test' relies on this.)  But the
-// import graph over n augmented packages may contain cycles.
-//
-// First, all the (unaugmented) non-test packages and their
-// dependencies are imported in the usual way; the loader reports an
-// error if it detects an import cycle.
-//
-// Then, each package P for which testing is desired is augmented by
-// the list P' of its in-package test files, by calling
-// (*types.Checker).Files.  This arrangement ensures that P' may
-// reference definitions within P, but P may not reference definitions
-// within P'.  Furthermore, P' may import any other package, including
-// ones that depend upon P, without an import cycle error.
-//
-// Consider two packages A and B, both of which have lists of
-// in-package test files we'll call A' and B', and which have the
-// following import graph edges:
-//    B  imports A
-//    B' imports A
-//    A' imports B
-// This last edge would be expected to create an error were it not
-// for the special type-checking discipline above.
-// Cycles of size greater than two are possible.  For example:
-//   compress/bzip2/bzip2_test.go (package bzip2)  imports "io/ioutil"
-//   io/ioutil/tempfile_test.go   (package ioutil) imports "regexp"
-//   regexp/exec_test.go          (package regexp) imports "compress/bzip2"
-//
-//
-// Concurrency
-// -----------
-//
-// Let us define the import dependency graph as follows.  Each node is a
-// list of files passed to (Checker).Files at once.  Many of these lists
-// are the production code of an importable Go package, so those nodes
-// are labelled by the package's path.  The remaining nodes are
-// ad hoc packages and lists of in-package *_test.go files that augment
-// an importable package; those nodes have no label.
-//
-// The edges of the graph represent import statements appearing within a
-// file.  An edge connects a node (a list of files) to the node it
-// imports, which is importable and thus always labelled.
-//
-// Loading is controlled by this dependency graph.
-//
-// To reduce I/O latency, we start loading a package's dependencies
-// asynchronously as soon as we've parsed its files and enumerated its
-// imports (scanImports).  This performs a preorder traversal of the
-// import dependency graph.
-//
-// To exploit hardware parallelism, we type-check unrelated packages in
-// parallel, where "unrelated" means not ordered by the partial order of
-// the import dependency graph.
-//
-// We use a concurrency-safe non-blocking cache (importer.imported) to
-// record the results of type-checking, whether success or failure.  An
-// entry is created in this cache by startLoad the first time the
-// package is imported.  The first goroutine to request an entry becomes
-// responsible for completing the task and broadcasting completion to
-// subsequent requestors, which block until then.
-//
-// Type checking occurs in (parallel) postorder: we cannot type-check a
-// set of files until we have loaded and type-checked all of their
-// immediate dependencies (and thus all of their transitive
-// dependencies). If the input were guaranteed free of import cycles,
-// this would be trivial: we could simply wait for completion of the
-// dependencies and then invoke the typechecker.
-//
-// But as we saw in the 'go test' section above, some cycles in the
-// import graph over packages are actually legal, so long as the
-// cycle-forming edge originates in the in-package test files that
-// augment the package.  This explains why the nodes of the import
-// dependency graph are not packages, but lists of files: the unlabelled
-// nodes avoid the cycles.  Consider packages A and B where B imports A
-// and A's in-package tests AT import B.  The naively constructed import
-// graph over packages would contain a cycle (A+AT) --> B --> (A+AT) but
-// the graph over lists of files is AT --> B --> A, where AT is an
-// unlabelled node.
-//
-// Awaiting completion of the dependencies in a cyclic graph would
-// deadlock, so we must materialize the import dependency graph (as
-// importer.graph) and check whether each import edge forms a cycle.  If
-// x imports y, and the graph already contains a path from y to x, then
-// there is an import cycle, in which case the processing of x must not
-// wait for the completion of processing of y.
-//
-// When the type-checker makes a callback (doImport) to the loader for a
-// given import edge, there are two possible cases.  In the normal case,
-// the dependency has already been completely type-checked; doImport
-// does a cache lookup and returns it.  In the cyclic case, the entry in
-// the cache is still necessarily incomplete, indicating a cycle.  We
-// perform the cycle check again to obtain the error message, and return
-// the error.
-//
-// The result of using concurrency is about a 2.5x speedup for stdlib_test.
diff --git a/vendor/golang.org/x/tools/go/loader/loader.go b/vendor/golang.org/x/tools/go/loader/loader.go
deleted file mode 100644
index bc12ca33d1..0000000000
--- a/vendor/golang.org/x/tools/go/loader/loader.go
+++ /dev/null
@@ -1,1086 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package loader
-
-// See doc.go for package documentation and implementation notes.
-
-import (
-	"errors"
-	"fmt"
-	"go/ast"
-	"go/build"
-	"go/parser"
-	"go/token"
-	"go/types"
-	"os"
-	"path/filepath"
-	"sort"
-	"strings"
-	"sync"
-	"time"
-
-	"golang.org/x/tools/go/ast/astutil"
-	"golang.org/x/tools/go/internal/cgo"
-)
-
-var ignoreVendor build.ImportMode
-
-const trace = false // show timing info for type-checking
-
-// Config specifies the configuration for loading a whole program from
-// Go source code.
-// The zero value for Config is a ready-to-use default configuration.
-type Config struct {
-	// Fset is the file set for the parser to use when loading the
-	// program.  If nil, it may be lazily initialized by any
-	// method of Config.
-	Fset *token.FileSet
-
-	// ParserMode specifies the mode to be used by the parser when
-	// loading source packages.
-	ParserMode parser.Mode
-
-	// TypeChecker contains options relating to the type checker.
-	//
-	// The supplied IgnoreFuncBodies is not used; the effective
-	// value comes from the TypeCheckFuncBodies func below.
-	// The supplied Import function is not used either.
-	TypeChecker types.Config
-
-	// TypeCheckFuncBodies is a predicate over package paths.
-	// A package for which the predicate is false will
-	// have its package-level declarations type checked, but not
-	// its function bodies; this can be used to quickly load
-	// dependencies from source.  If nil, all func bodies are type
-	// checked.
-	TypeCheckFuncBodies func(path string) bool
-
-	// If Build is non-nil, it is used to locate source packages.
-	// Otherwise &build.Default is used.
-	//
-	// By default, cgo is invoked to preprocess Go files that
-	// import the fake package "C".  This behaviour can be
-	// disabled by setting CGO_ENABLED=0 in the environment prior
-	// to startup, or by setting Build.CgoEnabled=false.
-	Build *build.Context
-
-	// The current directory, used for resolving relative package
-	// references such as "./go/loader".  If empty, os.Getwd will be
-	// used instead.
-	Cwd string
-
-	// If DisplayPath is non-nil, it is used to transform each
-	// file name obtained from Build.Import().  This can be used
-	// to prevent a virtualized build.Config's file names from
-	// leaking into the user interface.
-	DisplayPath func(path string) string
-
-	// If AllowErrors is true, Load will return a Program even
-	// if some of the its packages contained I/O, parser or type
-	// errors; such errors are accessible via PackageInfo.Errors.  If
-	// false, Load will fail if any package had an error.
-	AllowErrors bool
-
-	// CreatePkgs specifies a list of non-importable initial
-	// packages to create.  The resulting packages will appear in
-	// the corresponding elements of the Program.Created slice.
-	CreatePkgs []PkgSpec
-
-	// ImportPkgs specifies a set of initial packages to load.
-	// The map keys are package paths.
-	//
-	// The map value indicates whether to load tests.  If true, Load
-	// will add and type-check two lists of files to the package:
-	// non-test files followed by in-package *_test.go files.  In
-	// addition, it will append the external test package (if any)
-	// to Program.Created.
-	ImportPkgs map[string]bool
-
-	// FindPackage is called during Load to create the build.Package
-	// for a given import path from a given directory.
-	// If FindPackage is nil, (*build.Context).Import is used.
-	// A client may use this hook to adapt to a proprietary build
-	// system that does not follow the "go build" layout
-	// conventions, for example.
-	//
-	// It must be safe to call concurrently from multiple goroutines.
-	FindPackage func(ctxt *build.Context, importPath, fromDir string, mode build.ImportMode) (*build.Package, error)
-
-	// AfterTypeCheck is called immediately after a list of files
-	// has been type-checked and appended to info.Files.
-	//
-	// This optional hook function is the earliest opportunity for
-	// the client to observe the output of the type checker,
-	// which may be useful to reduce analysis latency when loading
-	// a large program.
-	//
-	// The function is permitted to modify info.Info, for instance
-	// to clear data structures that are no longer needed, which can
-	// dramatically reduce peak memory consumption.
-	//
-	// The function may be called twice for the same PackageInfo:
-	// once for the files of the package and again for the
-	// in-package test files.
-	//
-	// It must be safe to call concurrently from multiple goroutines.
-	AfterTypeCheck func(info *PackageInfo, files []*ast.File)
-}
-
-// A PkgSpec specifies a non-importable package to be created by Load.
-// Files are processed first, but typically only one of Files and
-// Filenames is provided.  The path needn't be globally unique.
-//
-// For vendoring purposes, the package's directory is the one that
-// contains the first file.
-type PkgSpec struct {
-	Path      string      // package path ("" => use package declaration)
-	Files     []*ast.File // ASTs of already-parsed files
-	Filenames []string    // names of files to be parsed
-}
-
-// A Program is a Go program loaded from source as specified by a Config.
-type Program struct {
-	Fset *token.FileSet // the file set for this program
-
-	// Created[i] contains the initial package whose ASTs or
-	// filenames were supplied by Config.CreatePkgs[i], followed by
-	// the external test package, if any, of each package in
-	// Config.ImportPkgs ordered by ImportPath.
-	//
-	// NOTE: these files must not import "C".  Cgo preprocessing is
-	// only performed on imported packages, not ad hoc packages.
-	//
-	// TODO(adonovan): we need to copy and adapt the logic of
-	// goFilesPackage (from $GOROOT/src/cmd/go/build.go) and make
-	// Config.Import and Config.Create methods return the same kind
-	// of entity, essentially a build.Package.
-	// Perhaps we can even reuse that type directly.
-	Created []*PackageInfo
-
-	// Imported contains the initially imported packages,
-	// as specified by Config.ImportPkgs.
-	Imported map[string]*PackageInfo
-
-	// AllPackages contains the PackageInfo of every package
-	// encountered by Load: all initial packages and all
-	// dependencies, including incomplete ones.
-	AllPackages map[*types.Package]*PackageInfo
-
-	// importMap is the canonical mapping of package paths to
-	// packages.  It contains all Imported initial packages, but not
-	// Created ones, and all imported dependencies.
-	importMap map[string]*types.Package
-}
-
-// PackageInfo holds the ASTs and facts derived by the type-checker
-// for a single package.
-//
-// Not mutated once exposed via the API.
-//
-type PackageInfo struct {
-	Pkg                   *types.Package
-	Importable            bool        // true if 'import "Pkg.Path()"' would resolve to this
-	TransitivelyErrorFree bool        // true if Pkg and all its dependencies are free of errors
-	Files                 []*ast.File // syntax trees for the package's files
-	Errors                []error     // non-nil if the package had errors
-	types.Info                        // type-checker deductions.
-	dir                   string      // package directory
-
-	checker   *types.Checker // transient type-checker state
-	errorFunc func(error)
-}
-
-func (info *PackageInfo) String() string { return info.Pkg.Path() }
-
-func (info *PackageInfo) appendError(err error) {
-	if info.errorFunc != nil {
-		info.errorFunc(err)
-	} else {
-		fmt.Fprintln(os.Stderr, err)
-	}
-	info.Errors = append(info.Errors, err)
-}
-
-func (conf *Config) fset() *token.FileSet {
-	if conf.Fset == nil {
-		conf.Fset = token.NewFileSet()
-	}
-	return conf.Fset
-}
-
-// ParseFile is a convenience function (intended for testing) that invokes
-// the parser using the Config's FileSet, which is initialized if nil.
-//
-// src specifies the parser input as a string, []byte, or io.Reader, and
-// filename is its apparent name.  If src is nil, the contents of
-// filename are read from the file system.
-//
-func (conf *Config) ParseFile(filename string, src interface{}) (*ast.File, error) {
-	// TODO(adonovan): use conf.build() etc like parseFiles does.
-	return parser.ParseFile(conf.fset(), filename, src, conf.ParserMode)
-}
-
-// FromArgsUsage is a partial usage message that applications calling
-// FromArgs may wish to include in their -help output.
-const FromArgsUsage = `
-<args> is a list of arguments denoting a set of initial packages.
-It may take one of two forms:
-
-1. A list of *.go source files.
-
-   All of the specified files are loaded, parsed and type-checked
-   as a single package.  All the files must belong to the same directory.
-
-2. A list of import paths, each denoting a package.
-
-   The package's directory is found relative to the $GOROOT and
-   $GOPATH using similar logic to 'go build', and the *.go files in
-   that directory are loaded, parsed and type-checked as a single
-   package.
-
-   In addition, all *_test.go files in the directory are then loaded
-   and parsed.  Those files whose package declaration equals that of
-   the non-*_test.go files are included in the primary package.  Test
-   files whose package declaration ends with "_test" are type-checked
-   as another package, the 'external' test package, so that a single
-   import path may denote two packages.  (Whether this behaviour is
-   enabled is tool-specific, and may depend on additional flags.)
-
-A '--' argument terminates the list of packages.
-`
-
-// FromArgs interprets args as a set of initial packages to load from
-// source and updates the configuration.  It returns the list of
-// unconsumed arguments.
-//
-// It is intended for use in command-line interfaces that require a
-// set of initial packages to be specified; see FromArgsUsage message
-// for details.
-//
-// Only superficial errors are reported at this stage; errors dependent
-// on I/O are detected during Load.
-//
-func (conf *Config) FromArgs(args []string, xtest bool) ([]string, error) {
-	var rest []string
-	for i, arg := range args {
-		if arg == "--" {
-			rest = args[i+1:]
-			args = args[:i]
-			break // consume "--" and return the remaining args
-		}
-	}
-
-	if len(args) > 0 && strings.HasSuffix(args[0], ".go") {
-		// Assume args is a list of a *.go files
-		// denoting a single ad hoc package.
-		for _, arg := range args {
-			if !strings.HasSuffix(arg, ".go") {
-				return nil, fmt.Errorf("named files must be .go files: %s", arg)
-			}
-		}
-		conf.CreateFromFilenames("", args...)
-	} else {
-		// Assume args are directories each denoting a
-		// package and (perhaps) an external test, iff xtest.
-		for _, arg := range args {
-			if xtest {
-				conf.ImportWithTests(arg)
-			} else {
-				conf.Import(arg)
-			}
-		}
-	}
-
-	return rest, nil
-}
-
-// CreateFromFilenames is a convenience function that adds
-// a conf.CreatePkgs entry to create a package of the specified *.go
-// files.
-//
-func (conf *Config) CreateFromFilenames(path string, filenames ...string) {
-	conf.CreatePkgs = append(conf.CreatePkgs, PkgSpec{Path: path, Filenames: filenames})
-}
-
-// CreateFromFiles is a convenience function that adds a conf.CreatePkgs
-// entry to create package of the specified path and parsed files.
-//
-func (conf *Config) CreateFromFiles(path string, files ...*ast.File) {
-	conf.CreatePkgs = append(conf.CreatePkgs, PkgSpec{Path: path, Files: files})
-}
-
-// ImportWithTests is a convenience function that adds path to
-// ImportPkgs, the set of initial source packages located relative to
-// $GOPATH.  The package will be augmented by any *_test.go files in
-// its directory that contain a "package x" (not "package x_test")
-// declaration.
-//
-// In addition, if any *_test.go files contain a "package x_test"
-// declaration, an additional package comprising just those files will
-// be added to CreatePkgs.
-//
-func (conf *Config) ImportWithTests(path string) { conf.addImport(path, true) }
-
-// Import is a convenience function that adds path to ImportPkgs, the
-// set of initial packages that will be imported from source.
-//
-func (conf *Config) Import(path string) { conf.addImport(path, false) }
-
-func (conf *Config) addImport(path string, tests bool) {
-	if path == "C" {
-		return // ignore; not a real package
-	}
-	if conf.ImportPkgs == nil {
-		conf.ImportPkgs = make(map[string]bool)
-	}
-	conf.ImportPkgs[path] = conf.ImportPkgs[path] || tests
-}
-
-// PathEnclosingInterval returns the PackageInfo and ast.Node that
-// contain source interval [start, end), and all the node's ancestors
-// up to the AST root.  It searches all ast.Files of all packages in prog.
-// exact is defined as for astutil.PathEnclosingInterval.
-//
-// The zero value is returned if not found.
-//
-func (prog *Program) PathEnclosingInterval(start, end token.Pos) (pkg *PackageInfo, path []ast.Node, exact bool) {
-	for _, info := range prog.AllPackages {
-		for _, f := range info.Files {
-			if f.Pos() == token.NoPos {
-				// This can happen if the parser saw
-				// too many errors and bailed out.
-				// (Use parser.AllErrors to prevent that.)
-				continue
-			}
-			if !tokenFileContainsPos(prog.Fset.File(f.Pos()), start) {
-				continue
-			}
-			if path, exact := astutil.PathEnclosingInterval(f, start, end); path != nil {
-				return info, path, exact
-			}
-		}
-	}
-	return nil, nil, false
-}
-
-// InitialPackages returns a new slice containing the set of initial
-// packages (Created + Imported) in unspecified order.
-//
-func (prog *Program) InitialPackages() []*PackageInfo {
-	infos := make([]*PackageInfo, 0, len(prog.Created)+len(prog.Imported))
-	infos = append(infos, prog.Created...)
-	for _, info := range prog.Imported {
-		infos = append(infos, info)
-	}
-	return infos
-}
-
-// Package returns the ASTs and results of type checking for the
-// specified package.
-func (prog *Program) Package(path string) *PackageInfo {
-	if info, ok := prog.AllPackages[prog.importMap[path]]; ok {
-		return info
-	}
-	for _, info := range prog.Created {
-		if path == info.Pkg.Path() {
-			return info
-		}
-	}
-	return nil
-}
-
-// ---------- Implementation ----------
-
-// importer holds the working state of the algorithm.
-type importer struct {
-	conf  *Config   // the client configuration
-	start time.Time // for logging
-
-	progMu sync.Mutex // guards prog
-	prog   *Program   // the resulting program
-
-	// findpkg is a memoization of FindPackage.
-	findpkgMu sync.Mutex // guards findpkg
-	findpkg   map[findpkgKey]*findpkgValue
-
-	importedMu sync.Mutex             // guards imported
-	imported   map[string]*importInfo // all imported packages (incl. failures) by import path
-
-	// import dependency graph: graph[x][y] => x imports y
-	//
-	// Since non-importable packages cannot be cyclic, we ignore
-	// their imports, thus we only need the subgraph over importable
-	// packages.  Nodes are identified by their import paths.
-	graphMu sync.Mutex
-	graph   map[string]map[string]bool
-}
-
-type findpkgKey struct {
-	importPath string
-	fromDir    string
-	mode       build.ImportMode
-}
-
-type findpkgValue struct {
-	ready chan struct{} // closed to broadcast readiness
-	bp    *build.Package
-	err   error
-}
-
-// importInfo tracks the success or failure of a single import.
-//
-// Upon completion, exactly one of info and err is non-nil:
-// info on successful creation of a package, err otherwise.
-// A successful package may still contain type errors.
-//
-type importInfo struct {
-	path     string        // import path
-	info     *PackageInfo  // results of typechecking (including errors)
-	complete chan struct{} // closed to broadcast that info is set.
-}
-
-// awaitCompletion blocks until ii is complete,
-// i.e. the info field is safe to inspect.
-func (ii *importInfo) awaitCompletion() {
-	<-ii.complete // wait for close
-}
-
-// Complete marks ii as complete.
-// Its info and err fields will not be subsequently updated.
-func (ii *importInfo) Complete(info *PackageInfo) {
-	if info == nil {
-		panic("info == nil")
-	}
-	ii.info = info
-	close(ii.complete)
-}
-
-type importError struct {
-	path string // import path
-	err  error  // reason for failure to create a package
-}
-
-// Load creates the initial packages specified by conf.{Create,Import}Pkgs,
-// loading their dependencies packages as needed.
-//
-// On success, Load returns a Program containing a PackageInfo for
-// each package.  On failure, it returns an error.
-//
-// If AllowErrors is true, Load will return a Program even if some
-// packages contained I/O, parser or type errors, or if dependencies
-// were missing.  (Such errors are accessible via PackageInfo.Errors.  If
-// false, Load will fail if any package had an error.
-//
-// It is an error if no packages were loaded.
-//
-func (conf *Config) Load() (*Program, error) {
-	// Create a simple default error handler for parse/type errors.
-	if conf.TypeChecker.Error == nil {
-		conf.TypeChecker.Error = func(e error) { fmt.Fprintln(os.Stderr, e) }
-	}
-
-	// Set default working directory for relative package references.
-	if conf.Cwd == "" {
-		var err error
-		conf.Cwd, err = os.Getwd()
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	// Install default FindPackage hook using go/build logic.
-	if conf.FindPackage == nil {
-		conf.FindPackage = (*build.Context).Import
-	}
-
-	prog := &Program{
-		Fset:        conf.fset(),
-		Imported:    make(map[string]*PackageInfo),
-		importMap:   make(map[string]*types.Package),
-		AllPackages: make(map[*types.Package]*PackageInfo),
-	}
-
-	imp := importer{
-		conf:     conf,
-		prog:     prog,
-		findpkg:  make(map[findpkgKey]*findpkgValue),
-		imported: make(map[string]*importInfo),
-		start:    time.Now(),
-		graph:    make(map[string]map[string]bool),
-	}
-
-	// -- loading proper (concurrent phase) --------------------------------
-
-	var errpkgs []string // packages that contained errors
-
-	// Load the initially imported packages and their dependencies,
-	// in parallel.
-	// No vendor check on packages imported from the command line.
-	infos, importErrors := imp.importAll("", conf.Cwd, conf.ImportPkgs, ignoreVendor)
-	for _, ie := range importErrors {
-		conf.TypeChecker.Error(ie.err) // failed to create package
-		errpkgs = append(errpkgs, ie.path)
-	}
-	for _, info := range infos {
-		prog.Imported[info.Pkg.Path()] = info
-	}
-
-	// Augment the designated initial packages by their tests.
-	// Dependencies are loaded in parallel.
-	var xtestPkgs []*build.Package
-	for importPath, augment := range conf.ImportPkgs {
-		if !augment {
-			continue
-		}
-
-		// No vendor check on packages imported from command line.
-		bp, err := imp.findPackage(importPath, conf.Cwd, ignoreVendor)
-		if err != nil {
-			// Package not found, or can't even parse package declaration.
-			// Already reported by previous loop; ignore it.
-			continue
-		}
-
-		// Needs external test package?
-		if len(bp.XTestGoFiles) > 0 {
-			xtestPkgs = append(xtestPkgs, bp)
-		}
-
-		// Consult the cache using the canonical package path.
-		path := bp.ImportPath
-		imp.importedMu.Lock() // (unnecessary, we're sequential here)
-		ii, ok := imp.imported[path]
-		// Paranoid checks added due to issue #11012.
-		if !ok {
-			// Unreachable.
-			// The previous loop called importAll and thus
-			// startLoad for each path in ImportPkgs, which
-			// populates imp.imported[path] with a non-zero value.
-			panic(fmt.Sprintf("imported[%q] not found", path))
-		}
-		if ii == nil {
-			// Unreachable.
-			// The ii values in this loop are the same as in
-			// the previous loop, which enforced the invariant
-			// that at least one of ii.err and ii.info is non-nil.
-			panic(fmt.Sprintf("imported[%q] == nil", path))
-		}
-		if ii.info == nil {
-			// Unreachable.
-			// awaitCompletion has the postcondition
-			// ii.info != nil.
-			panic(fmt.Sprintf("imported[%q].info = nil", path))
-		}
-		info := ii.info
-		imp.importedMu.Unlock()
-
-		// Parse the in-package test files.
-		files, errs := imp.conf.parsePackageFiles(bp, 't')
-		for _, err := range errs {
-			info.appendError(err)
-		}
-
-		// The test files augmenting package P cannot be imported,
-		// but may import packages that import P,
-		// so we must disable the cycle check.
-		imp.addFiles(info, files, false)
-	}
-
-	createPkg := func(path, dir string, files []*ast.File, errs []error) {
-		info := imp.newPackageInfo(path, dir)
-		for _, err := range errs {
-			info.appendError(err)
-		}
-
-		// Ad hoc packages are non-importable,
-		// so no cycle check is needed.
-		// addFiles loads dependencies in parallel.
-		imp.addFiles(info, files, false)
-		prog.Created = append(prog.Created, info)
-	}
-
-	// Create packages specified by conf.CreatePkgs.
-	for _, cp := range conf.CreatePkgs {
-		files, errs := parseFiles(conf.fset(), conf.build(), nil, conf.Cwd, cp.Filenames, conf.ParserMode)
-		files = append(files, cp.Files...)
-
-		path := cp.Path
-		if path == "" {
-			if len(files) > 0 {
-				path = files[0].Name.Name
-			} else {
-				path = "(unnamed)"
-			}
-		}
-
-		dir := conf.Cwd
-		if len(files) > 0 && files[0].Pos().IsValid() {
-			dir = filepath.Dir(conf.fset().File(files[0].Pos()).Name())
-		}
-		createPkg(path, dir, files, errs)
-	}
-
-	// Create external test packages.
-	sort.Sort(byImportPath(xtestPkgs))
-	for _, bp := range xtestPkgs {
-		files, errs := imp.conf.parsePackageFiles(bp, 'x')
-		createPkg(bp.ImportPath+"_test", bp.Dir, files, errs)
-	}
-
-	// -- finishing up (sequential) ----------------------------------------
-
-	if len(prog.Imported)+len(prog.Created) == 0 {
-		return nil, errors.New("no initial packages were loaded")
-	}
-
-	// Create infos for indirectly imported packages.
-	// e.g. incomplete packages without syntax, loaded from export data.
-	for _, obj := range prog.importMap {
-		info := prog.AllPackages[obj]
-		if info == nil {
-			prog.AllPackages[obj] = &PackageInfo{Pkg: obj, Importable: true}
-		} else {
-			// finished
-			info.checker = nil
-			info.errorFunc = nil
-		}
-	}
-
-	if !conf.AllowErrors {
-		// Report errors in indirectly imported packages.
-		for _, info := range prog.AllPackages {
-			if len(info.Errors) > 0 {
-				errpkgs = append(errpkgs, info.Pkg.Path())
-			}
-		}
-		if errpkgs != nil {
-			var more string
-			if len(errpkgs) > 3 {
-				more = fmt.Sprintf(" and %d more", len(errpkgs)-3)
-				errpkgs = errpkgs[:3]
-			}
-			return nil, fmt.Errorf("couldn't load packages due to errors: %s%s",
-				strings.Join(errpkgs, ", "), more)
-		}
-	}
-
-	markErrorFreePackages(prog.AllPackages)
-
-	return prog, nil
-}
-
-type byImportPath []*build.Package
-
-func (b byImportPath) Len() int           { return len(b) }
-func (b byImportPath) Less(i, j int) bool { return b[i].ImportPath < b[j].ImportPath }
-func (b byImportPath) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
-
-// markErrorFreePackages sets the TransitivelyErrorFree flag on all
-// applicable packages.
-func markErrorFreePackages(allPackages map[*types.Package]*PackageInfo) {
-	// Build the transpose of the import graph.
-	importedBy := make(map[*types.Package]map[*types.Package]bool)
-	for P := range allPackages {
-		for _, Q := range P.Imports() {
-			clients, ok := importedBy[Q]
-			if !ok {
-				clients = make(map[*types.Package]bool)
-				importedBy[Q] = clients
-			}
-			clients[P] = true
-		}
-	}
-
-	// Find all packages reachable from some error package.
-	reachable := make(map[*types.Package]bool)
-	var visit func(*types.Package)
-	visit = func(p *types.Package) {
-		if !reachable[p] {
-			reachable[p] = true
-			for q := range importedBy[p] {
-				visit(q)
-			}
-		}
-	}
-	for _, info := range allPackages {
-		if len(info.Errors) > 0 {
-			visit(info.Pkg)
-		}
-	}
-
-	// Mark the others as "transitively error-free".
-	for _, info := range allPackages {
-		if !reachable[info.Pkg] {
-			info.TransitivelyErrorFree = true
-		}
-	}
-}
-
-// build returns the effective build context.
-func (conf *Config) build() *build.Context {
-	if conf.Build != nil {
-		return conf.Build
-	}
-	return &build.Default
-}
-
-// parsePackageFiles enumerates the files belonging to package path,
-// then loads, parses and returns them, plus a list of I/O or parse
-// errors that were encountered.
-//
-// 'which' indicates which files to include:
-//    'g': include non-test *.go source files (GoFiles + processed CgoFiles)
-//    't': include in-package *_test.go source files (TestGoFiles)
-//    'x': include external *_test.go source files. (XTestGoFiles)
-//
-func (conf *Config) parsePackageFiles(bp *build.Package, which rune) ([]*ast.File, []error) {
-	if bp.ImportPath == "unsafe" {
-		return nil, nil
-	}
-	var filenames []string
-	switch which {
-	case 'g':
-		filenames = bp.GoFiles
-	case 't':
-		filenames = bp.TestGoFiles
-	case 'x':
-		filenames = bp.XTestGoFiles
-	default:
-		panic(which)
-	}
-
-	files, errs := parseFiles(conf.fset(), conf.build(), conf.DisplayPath, bp.Dir, filenames, conf.ParserMode)
-
-	// Preprocess CgoFiles and parse the outputs (sequentially).
-	if which == 'g' && bp.CgoFiles != nil {
-		cgofiles, err := cgo.ProcessFiles(bp, conf.fset(), conf.DisplayPath, conf.ParserMode)
-		if err != nil {
-			errs = append(errs, err)
-		} else {
-			files = append(files, cgofiles...)
-		}
-	}
-
-	return files, errs
-}
-
-// doImport imports the package denoted by path.
-// It implements the types.Importer signature.
-//
-// It returns an error if a package could not be created
-// (e.g. go/build or parse error), but type errors are reported via
-// the types.Config.Error callback (the first of which is also saved
-// in the package's PackageInfo).
-//
-// Idempotent.
-//
-func (imp *importer) doImport(from *PackageInfo, to string) (*types.Package, error) {
-	if to == "C" {
-		// This should be unreachable, but ad hoc packages are
-		// not currently subject to cgo preprocessing.
-		// See https://golang.org/issue/11627.
-		return nil, fmt.Errorf(`the loader doesn't cgo-process ad hoc packages like %q; see Go issue 11627`,
-			from.Pkg.Path())
-	}
-
-	bp, err := imp.findPackage(to, from.dir, 0)
-	if err != nil {
-		return nil, err
-	}
-
-	// The standard unsafe package is handled specially,
-	// and has no PackageInfo.
-	if bp.ImportPath == "unsafe" {
-		return types.Unsafe, nil
-	}
-
-	// Look for the package in the cache using its canonical path.
-	path := bp.ImportPath
-	imp.importedMu.Lock()
-	ii := imp.imported[path]
-	imp.importedMu.Unlock()
-	if ii == nil {
-		panic("internal error: unexpected import: " + path)
-	}
-	if ii.info != nil {
-		return ii.info.Pkg, nil
-	}
-
-	// Import of incomplete package: this indicates a cycle.
-	fromPath := from.Pkg.Path()
-	if cycle := imp.findPath(path, fromPath); cycle != nil {
-		// Normalize cycle: start from alphabetically largest node.
-		pos, start := -1, ""
-		for i, s := range cycle {
-			if pos < 0 || s > start {
-				pos, start = i, s
-			}
-		}
-		cycle = append(cycle, cycle[:pos]...)[pos:] // rotate cycle to start from largest
-		cycle = append(cycle, cycle[0])             // add start node to end to show cycliness
-		return nil, fmt.Errorf("import cycle: %s", strings.Join(cycle, " -> "))
-	}
-
-	panic("internal error: import of incomplete (yet acyclic) package: " + fromPath)
-}
-
-// findPackage locates the package denoted by the importPath in the
-// specified directory.
-func (imp *importer) findPackage(importPath, fromDir string, mode build.ImportMode) (*build.Package, error) {
-	// We use a non-blocking duplicate-suppressing cache (gopl.io §9.7)
-	// to avoid holding the lock around FindPackage.
-	key := findpkgKey{importPath, fromDir, mode}
-	imp.findpkgMu.Lock()
-	v, ok := imp.findpkg[key]
-	if ok {
-		// cache hit
-		imp.findpkgMu.Unlock()
-
-		<-v.ready // wait for entry to become ready
-	} else {
-		// Cache miss: this goroutine becomes responsible for
-		// populating the map entry and broadcasting its readiness.
-		v = &findpkgValue{ready: make(chan struct{})}
-		imp.findpkg[key] = v
-		imp.findpkgMu.Unlock()
-
-		ioLimit <- true
-		v.bp, v.err = imp.conf.FindPackage(imp.conf.build(), importPath, fromDir, mode)
-		<-ioLimit
-
-		if _, ok := v.err.(*build.NoGoError); ok {
-			v.err = nil // empty directory is not an error
-		}
-
-		close(v.ready) // broadcast ready condition
-	}
-	return v.bp, v.err
-}
-
-// importAll loads, parses, and type-checks the specified packages in
-// parallel and returns their completed importInfos in unspecified order.
-//
-// fromPath is the package path of the importing package, if it is
-// importable, "" otherwise.  It is used for cycle detection.
-//
-// fromDir is the directory containing the import declaration that
-// caused these imports.
-//
-func (imp *importer) importAll(fromPath, fromDir string, imports map[string]bool, mode build.ImportMode) (infos []*PackageInfo, errors []importError) {
-	// TODO(adonovan): opt: do the loop in parallel once
-	// findPackage is non-blocking.
-	var pending []*importInfo
-	for importPath := range imports {
-		bp, err := imp.findPackage(importPath, fromDir, mode)
-		if err != nil {
-			errors = append(errors, importError{
-				path: importPath,
-				err:  err,
-			})
-			continue
-		}
-		pending = append(pending, imp.startLoad(bp))
-	}
-
-	if fromPath != "" {
-		// We're loading a set of imports.
-		//
-		// We must record graph edges from the importing package
-		// to its dependencies, and check for cycles.
-		imp.graphMu.Lock()
-		deps, ok := imp.graph[fromPath]
-		if !ok {
-			deps = make(map[string]bool)
-			imp.graph[fromPath] = deps
-		}
-		for _, ii := range pending {
-			deps[ii.path] = true
-		}
-		imp.graphMu.Unlock()
-	}
-
-	for _, ii := range pending {
-		if fromPath != "" {
-			if cycle := imp.findPath(ii.path, fromPath); cycle != nil {
-				// Cycle-forming import: we must not await its
-				// completion since it would deadlock.
-				//
-				// We don't record the error in ii since
-				// the error is really associated with the
-				// cycle-forming edge, not the package itself.
-				// (Also it would complicate the
-				// invariants of importPath completion.)
-				if trace {
-					fmt.Fprintf(os.Stderr, "import cycle: %q\n", cycle)
-				}
-				continue
-			}
-		}
-		ii.awaitCompletion()
-		infos = append(infos, ii.info)
-	}
-
-	return infos, errors
-}
-
-// findPath returns an arbitrary path from 'from' to 'to' in the import
-// graph, or nil if there was none.
-func (imp *importer) findPath(from, to string) []string {
-	imp.graphMu.Lock()
-	defer imp.graphMu.Unlock()
-
-	seen := make(map[string]bool)
-	var search func(stack []string, importPath string) []string
-	search = func(stack []string, importPath string) []string {
-		if !seen[importPath] {
-			seen[importPath] = true
-			stack = append(stack, importPath)
-			if importPath == to {
-				return stack
-			}
-			for x := range imp.graph[importPath] {
-				if p := search(stack, x); p != nil {
-					return p
-				}
-			}
-		}
-		return nil
-	}
-	return search(make([]string, 0, 20), from)
-}
-
-// startLoad initiates the loading, parsing and type-checking of the
-// specified package and its dependencies, if it has not already begun.
-//
-// It returns an importInfo, not necessarily in a completed state.  The
-// caller must call awaitCompletion() before accessing its info field.
-//
-// startLoad is concurrency-safe and idempotent.
-//
-func (imp *importer) startLoad(bp *build.Package) *importInfo {
-	path := bp.ImportPath
-	imp.importedMu.Lock()
-	ii, ok := imp.imported[path]
-	if !ok {
-		ii = &importInfo{path: path, complete: make(chan struct{})}
-		imp.imported[path] = ii
-		go func() {
-			info := imp.load(bp)
-			ii.Complete(info)
-		}()
-	}
-	imp.importedMu.Unlock()
-
-	return ii
-}
-
-// load implements package loading by parsing Go source files
-// located by go/build.
-func (imp *importer) load(bp *build.Package) *PackageInfo {
-	info := imp.newPackageInfo(bp.ImportPath, bp.Dir)
-	info.Importable = true
-	files, errs := imp.conf.parsePackageFiles(bp, 'g')
-	for _, err := range errs {
-		info.appendError(err)
-	}
-
-	imp.addFiles(info, files, true)
-
-	imp.progMu.Lock()
-	imp.prog.importMap[bp.ImportPath] = info.Pkg
-	imp.progMu.Unlock()
-
-	return info
-}
-
-// addFiles adds and type-checks the specified files to info, loading
-// their dependencies if needed.  The order of files determines the
-// package initialization order.  It may be called multiple times on the
-// same package.  Errors are appended to the info.Errors field.
-//
-// cycleCheck determines whether the imports within files create
-// dependency edges that should be checked for potential cycles.
-//
-func (imp *importer) addFiles(info *PackageInfo, files []*ast.File, cycleCheck bool) {
-	// Ensure the dependencies are loaded, in parallel.
-	var fromPath string
-	if cycleCheck {
-		fromPath = info.Pkg.Path()
-	}
-	// TODO(adonovan): opt: make the caller do scanImports.
-	// Callers with a build.Package can skip it.
-	imp.importAll(fromPath, info.dir, scanImports(files), 0)
-
-	if trace {
-		fmt.Fprintf(os.Stderr, "%s: start %q (%d)\n",
-			time.Since(imp.start), info.Pkg.Path(), len(files))
-	}
-
-	// Don't call checker.Files on Unsafe, even with zero files,
-	// because it would mutate the package, which is a global.
-	if info.Pkg == types.Unsafe {
-		if len(files) > 0 {
-			panic(`"unsafe" package contains unexpected files`)
-		}
-	} else {
-		// Ignore the returned (first) error since we
-		// already collect them all in the PackageInfo.
-		info.checker.Files(files)
-		info.Files = append(info.Files, files...)
-	}
-
-	if imp.conf.AfterTypeCheck != nil {
-		imp.conf.AfterTypeCheck(info, files)
-	}
-
-	if trace {
-		fmt.Fprintf(os.Stderr, "%s: stop %q\n",
-			time.Since(imp.start), info.Pkg.Path())
-	}
-}
-
-func (imp *importer) newPackageInfo(path, dir string) *PackageInfo {
-	var pkg *types.Package
-	if path == "unsafe" {
-		pkg = types.Unsafe
-	} else {
-		pkg = types.NewPackage(path, "")
-	}
-	info := &PackageInfo{
-		Pkg: pkg,
-		Info: types.Info{
-			Types:      make(map[ast.Expr]types.TypeAndValue),
-			Defs:       make(map[*ast.Ident]types.Object),
-			Uses:       make(map[*ast.Ident]types.Object),
-			Implicits:  make(map[ast.Node]types.Object),
-			Scopes:     make(map[ast.Node]*types.Scope),
-			Selections: make(map[*ast.SelectorExpr]*types.Selection),
-		},
-		errorFunc: imp.conf.TypeChecker.Error,
-		dir:       dir,
-	}
-
-	// Copy the types.Config so we can vary it across PackageInfos.
-	tc := imp.conf.TypeChecker
-	tc.IgnoreFuncBodies = false
-	if f := imp.conf.TypeCheckFuncBodies; f != nil {
-		tc.IgnoreFuncBodies = !f(path)
-	}
-	tc.Importer = closure{imp, info}
-	tc.Error = info.appendError // appendError wraps the user's Error function
-
-	info.checker = types.NewChecker(&tc, imp.conf.fset(), pkg, &info.Info)
-	imp.progMu.Lock()
-	imp.prog.AllPackages[pkg] = info
-	imp.progMu.Unlock()
-	return info
-}
-
-type closure struct {
-	imp  *importer
-	info *PackageInfo
-}
-
-func (c closure) Import(to string) (*types.Package, error) { return c.imp.doImport(c.info, to) }
diff --git a/vendor/golang.org/x/tools/go/loader/util.go b/vendor/golang.org/x/tools/go/loader/util.go
deleted file mode 100644
index 7f38dd7407..0000000000
--- a/vendor/golang.org/x/tools/go/loader/util.go
+++ /dev/null
@@ -1,124 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package loader
-
-import (
-	"go/ast"
-	"go/build"
-	"go/parser"
-	"go/token"
-	"io"
-	"os"
-	"strconv"
-	"sync"
-
-	"golang.org/x/tools/go/buildutil"
-)
-
-// We use a counting semaphore to limit
-// the number of parallel I/O calls per process.
-var ioLimit = make(chan bool, 10)
-
-// parseFiles parses the Go source files within directory dir and
-// returns the ASTs of the ones that could be at least partially parsed,
-// along with a list of I/O and parse errors encountered.
-//
-// I/O is done via ctxt, which may specify a virtual file system.
-// displayPath is used to transform the filenames attached to the ASTs.
-//
-func parseFiles(fset *token.FileSet, ctxt *build.Context, displayPath func(string) string, dir string, files []string, mode parser.Mode) ([]*ast.File, []error) {
-	if displayPath == nil {
-		displayPath = func(path string) string { return path }
-	}
-	var wg sync.WaitGroup
-	n := len(files)
-	parsed := make([]*ast.File, n)
-	errors := make([]error, n)
-	for i, file := range files {
-		if !buildutil.IsAbsPath(ctxt, file) {
-			file = buildutil.JoinPath(ctxt, dir, file)
-		}
-		wg.Add(1)
-		go func(i int, file string) {
-			ioLimit <- true // wait
-			defer func() {
-				wg.Done()
-				<-ioLimit // signal
-			}()
-			var rd io.ReadCloser
-			var err error
-			if ctxt.OpenFile != nil {
-				rd, err = ctxt.OpenFile(file)
-			} else {
-				rd, err = os.Open(file)
-			}
-			if err != nil {
-				errors[i] = err // open failed
-				return
-			}
-
-			// ParseFile may return both an AST and an error.
-			parsed[i], errors[i] = parser.ParseFile(fset, displayPath(file), rd, mode)
-			rd.Close()
-		}(i, file)
-	}
-	wg.Wait()
-
-	// Eliminate nils, preserving order.
-	var o int
-	for _, f := range parsed {
-		if f != nil {
-			parsed[o] = f
-			o++
-		}
-	}
-	parsed = parsed[:o]
-
-	o = 0
-	for _, err := range errors {
-		if err != nil {
-			errors[o] = err
-			o++
-		}
-	}
-	errors = errors[:o]
-
-	return parsed, errors
-}
-
-// scanImports returns the set of all import paths from all
-// import specs in the specified files.
-func scanImports(files []*ast.File) map[string]bool {
-	imports := make(map[string]bool)
-	for _, f := range files {
-		for _, decl := range f.Decls {
-			if decl, ok := decl.(*ast.GenDecl); ok && decl.Tok == token.IMPORT {
-				for _, spec := range decl.Specs {
-					spec := spec.(*ast.ImportSpec)
-
-					// NB: do not assume the program is well-formed!
-					path, err := strconv.Unquote(spec.Path.Value)
-					if err != nil {
-						continue // quietly ignore the error
-					}
-					if path == "C" {
-						continue // skip pseudopackage
-					}
-					imports[path] = true
-				}
-			}
-		}
-	}
-	return imports
-}
-
-// ---------- Internal helpers ----------
-
-// TODO(adonovan): make this a method: func (*token.File) Contains(token.Pos)
-func tokenFileContainsPos(f *token.File, pos token.Pos) bool {
-	p := int(pos)
-	base := f.Base()
-	return base <= p && p < base+f.Size()
-}
diff --git a/vendor/golang.org/x/tools/go/packages/doc.go b/vendor/golang.org/x/tools/go/packages/doc.go
deleted file mode 100644
index 4bfe28a51f..0000000000
--- a/vendor/golang.org/x/tools/go/packages/doc.go
+++ /dev/null
@@ -1,221 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-/*
-Package packages loads Go packages for inspection and analysis.
-
-The Load function takes as input a list of patterns and return a list of Package
-structs describing individual packages matched by those patterns.
-The LoadMode controls the amount of detail in the loaded packages.
-
-Load passes most patterns directly to the underlying build tool,
-but all patterns with the prefix "query=", where query is a
-non-empty string of letters from [a-z], are reserved and may be
-interpreted as query operators.
-
-Two query operators are currently supported: "file" and "pattern".
-
-The query "file=path/to/file.go" matches the package or packages enclosing
-the Go source file path/to/file.go.  For example "file=~/go/src/fmt/print.go"
-might return the packages "fmt" and "fmt [fmt.test]".
-
-The query "pattern=string" causes "string" to be passed directly to
-the underlying build tool. In most cases this is unnecessary,
-but an application can use Load("pattern=" + x) as an escaping mechanism
-to ensure that x is not interpreted as a query operator if it contains '='.
-
-All other query operators are reserved for future use and currently
-cause Load to report an error.
-
-The Package struct provides basic information about the package, including
-
-  - ID, a unique identifier for the package in the returned set;
-  - GoFiles, the names of the package's Go source files;
-  - Imports, a map from source import strings to the Packages they name;
-  - Types, the type information for the package's exported symbols;
-  - Syntax, the parsed syntax trees for the package's source code; and
-  - TypeInfo, the result of a complete type-check of the package syntax trees.
-
-(See the documentation for type Package for the complete list of fields
-and more detailed descriptions.)
-
-For example,
-
-	Load(nil, "bytes", "unicode...")
-
-returns four Package structs describing the standard library packages
-bytes, unicode, unicode/utf16, and unicode/utf8. Note that one pattern
-can match multiple packages and that a package might be matched by
-multiple patterns: in general it is not possible to determine which
-packages correspond to which patterns.
-
-Note that the list returned by Load contains only the packages matched
-by the patterns. Their dependencies can be found by walking the import
-graph using the Imports fields.
-
-The Load function can be configured by passing a pointer to a Config as
-the first argument. A nil Config is equivalent to the zero Config, which
-causes Load to run in LoadFiles mode, collecting minimal information.
-See the documentation for type Config for details.
-
-As noted earlier, the Config.Mode controls the amount of detail
-reported about the loaded packages. See the documentation for type LoadMode
-for details.
-
-Most tools should pass their command-line arguments (after any flags)
-uninterpreted to the loader, so that the loader can interpret them
-according to the conventions of the underlying build system.
-See the Example function for typical usage.
-
-*/
-package packages // import "golang.org/x/tools/go/packages"
-
-/*
-
-Motivation and design considerations
-
-The new package's design solves problems addressed by two existing
-packages: go/build, which locates and describes packages, and
-golang.org/x/tools/go/loader, which loads, parses and type-checks them.
-The go/build.Package structure encodes too much of the 'go build' way
-of organizing projects, leaving us in need of a data type that describes a
-package of Go source code independent of the underlying build system.
-We wanted something that works equally well with go build and vgo, and
-also other build systems such as Bazel and Blaze, making it possible to
-construct analysis tools that work in all these environments.
-Tools such as errcheck and staticcheck were essentially unavailable to
-the Go community at Google, and some of Google's internal tools for Go
-are unavailable externally.
-This new package provides a uniform way to obtain package metadata by
-querying each of these build systems, optionally supporting their
-preferred command-line notations for packages, so that tools integrate
-neatly with users' build environments. The Metadata query function
-executes an external query tool appropriate to the current workspace.
-
-Loading packages always returns the complete import graph "all the way down",
-even if all you want is information about a single package, because the query
-mechanisms of all the build systems we currently support ({go,vgo} list, and
-blaze/bazel aspect-based query) cannot provide detailed information
-about one package without visiting all its dependencies too, so there is
-no additional asymptotic cost to providing transitive information.
-(This property might not be true of a hypothetical 5th build system.)
-
-In calls to TypeCheck, all initial packages, and any package that
-transitively depends on one of them, must be loaded from source.
-Consider A->B->C->D->E: if A,C are initial, A,B,C must be loaded from
-source; D may be loaded from export data, and E may not be loaded at all
-(though it's possible that D's export data mentions it, so a
-types.Package may be created for it and exposed.)
-
-The old loader had a feature to suppress type-checking of function
-bodies on a per-package basis, primarily intended to reduce the work of
-obtaining type information for imported packages. Now that imports are
-satisfied by export data, the optimization no longer seems necessary.
-
-Despite some early attempts, the old loader did not exploit export data,
-instead always using the equivalent of WholeProgram mode. This was due
-to the complexity of mixing source and export data packages (now
-resolved by the upward traversal mentioned above), and because export data
-files were nearly always missing or stale. Now that 'go build' supports
-caching, all the underlying build systems can guarantee to produce
-export data in a reasonable (amortized) time.
-
-Test "main" packages synthesized by the build system are now reported as
-first-class packages, avoiding the need for clients (such as go/ssa) to
-reinvent this generation logic.
-
-One way in which go/packages is simpler than the old loader is in its
-treatment of in-package tests. In-package tests are packages that
-consist of all the files of the library under test, plus the test files.
-The old loader constructed in-package tests by a two-phase process of
-mutation called "augmentation": first it would construct and type check
-all the ordinary library packages and type-check the packages that
-depend on them; then it would add more (test) files to the package and
-type-check again. This two-phase approach had four major problems:
-1) in processing the tests, the loader modified the library package,
-   leaving no way for a client application to see both the test
-   package and the library package; one would mutate into the other.
-2) because test files can declare additional methods on types defined in
-   the library portion of the package, the dispatch of method calls in
-   the library portion was affected by the presence of the test files.
-   This should have been a clue that the packages were logically
-   different.
-3) this model of "augmentation" assumed at most one in-package test
-   per library package, which is true of projects using 'go build',
-   but not other build systems.
-4) because of the two-phase nature of test processing, all packages that
-   import the library package had to be processed before augmentation,
-   forcing a "one-shot" API and preventing the client from calling Load
-   in several times in sequence as is now possible in WholeProgram mode.
-   (TypeCheck mode has a similar one-shot restriction for a different reason.)
-
-Early drafts of this package supported "multi-shot" operation.
-Although it allowed clients to make a sequence of calls (or concurrent
-calls) to Load, building up the graph of Packages incrementally,
-it was of marginal value: it complicated the API
-(since it allowed some options to vary across calls but not others),
-it complicated the implementation,
-it cannot be made to work in Types mode, as explained above,
-and it was less efficient than making one combined call (when this is possible).
-Among the clients we have inspected, none made multiple calls to load
-but could not be easily and satisfactorily modified to make only a single call.
-However, applications changes may be required.
-For example, the ssadump command loads the user-specified packages
-and in addition the runtime package.  It is tempting to simply append
-"runtime" to the user-provided list, but that does not work if the user
-specified an ad-hoc package such as [a.go b.go].
-Instead, ssadump no longer requests the runtime package,
-but seeks it among the dependencies of the user-specified packages,
-and emits an error if it is not found.
-
-Overlays: The Overlay field in the Config allows providing alternate contents
-for Go source files, by providing a mapping from file path to contents.
-go/packages will pull in new imports added in overlay files when go/packages
-is run in LoadImports mode or greater.
-Overlay support for the go list driver isn't complete yet: if the file doesn't
-exist on disk, it will only be recognized in an overlay if it is a non-test file
-and the package would be reported even without the overlay.
-
-Questions & Tasks
-
-- Add GOARCH/GOOS?
-  They are not portable concepts, but could be made portable.
-  Our goal has been to allow users to express themselves using the conventions
-  of the underlying build system: if the build system honors GOARCH
-  during a build and during a metadata query, then so should
-  applications built atop that query mechanism.
-  Conversely, if the target architecture of the build is determined by
-  command-line flags, the application can pass the relevant
-  flags through to the build system using a command such as:
-    myapp -query_flag="--cpu=amd64" -query_flag="--os=darwin"
-  However, this approach is low-level, unwieldy, and non-portable.
-  GOOS and GOARCH seem important enough to warrant a dedicated option.
-
-- How should we handle partial failures such as a mixture of good and
-  malformed patterns, existing and non-existent packages, successful and
-  failed builds, import failures, import cycles, and so on, in a call to
-  Load?
-
-- Support bazel, blaze, and go1.10 list, not just go1.11 list.
-
-- Handle (and test) various partial success cases, e.g.
-  a mixture of good packages and:
-  invalid patterns
-  nonexistent packages
-  empty packages
-  packages with malformed package or import declarations
-  unreadable files
-  import cycles
-  other parse errors
-  type errors
-  Make sure we record errors at the correct place in the graph.
-
-- Missing packages among initial arguments are not reported.
-  Return bogus packages for them, like golist does.
-
-- "undeclared name" errors (for example) are reported out of source file
-  order. I suspect this is due to the breadth-first resolution now used
-  by go/types. Is that a bug? Discuss with gri.
-
-*/
diff --git a/vendor/golang.org/x/tools/go/packages/external.go b/vendor/golang.org/x/tools/go/packages/external.go
deleted file mode 100644
index 7242a0a7d2..0000000000
--- a/vendor/golang.org/x/tools/go/packages/external.go
+++ /dev/null
@@ -1,101 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file enables an external tool to intercept package requests.
-// If the tool is present then its results are used in preference to
-// the go list command.
-
-package packages
-
-import (
-	"bytes"
-	"encoding/json"
-	"fmt"
-	exec "golang.org/x/sys/execabs"
-	"os"
-	"strings"
-)
-
-// The Driver Protocol
-//
-// The driver, given the inputs to a call to Load, returns metadata about the packages specified.
-// This allows for different build systems to support go/packages by telling go/packages how the
-// packages' source is organized.
-// The driver is a binary, either specified by the GOPACKAGESDRIVER environment variable or in
-// the path as gopackagesdriver. It's given the inputs to load in its argv. See the package
-// documentation in doc.go for the full description of the patterns that need to be supported.
-// A driver receives as a JSON-serialized driverRequest struct in standard input and will
-// produce a JSON-serialized driverResponse (see definition in packages.go) in its standard output.
-
-// driverRequest is used to provide the portion of Load's Config that is needed by a driver.
-type driverRequest struct {
-	Mode LoadMode `json:"mode"`
-	// Env specifies the environment the underlying build system should be run in.
-	Env []string `json:"env"`
-	// BuildFlags are flags that should be passed to the underlying build system.
-	BuildFlags []string `json:"build_flags"`
-	// Tests specifies whether the patterns should also return test packages.
-	Tests bool `json:"tests"`
-	// Overlay maps file paths (relative to the driver's working directory) to the byte contents
-	// of overlay files.
-	Overlay map[string][]byte `json:"overlay"`
-}
-
-// findExternalDriver returns the file path of a tool that supplies
-// the build system package structure, or "" if not found."
-// If GOPACKAGESDRIVER is set in the environment findExternalTool returns its
-// value, otherwise it searches for a binary named gopackagesdriver on the PATH.
-func findExternalDriver(cfg *Config) driver {
-	const toolPrefix = "GOPACKAGESDRIVER="
-	tool := ""
-	for _, env := range cfg.Env {
-		if val := strings.TrimPrefix(env, toolPrefix); val != env {
-			tool = val
-		}
-	}
-	if tool != "" && tool == "off" {
-		return nil
-	}
-	if tool == "" {
-		var err error
-		tool, err = exec.LookPath("gopackagesdriver")
-		if err != nil {
-			return nil
-		}
-	}
-	return func(cfg *Config, words ...string) (*driverResponse, error) {
-		req, err := json.Marshal(driverRequest{
-			Mode:       cfg.Mode,
-			Env:        cfg.Env,
-			BuildFlags: cfg.BuildFlags,
-			Tests:      cfg.Tests,
-			Overlay:    cfg.Overlay,
-		})
-		if err != nil {
-			return nil, fmt.Errorf("failed to encode message to driver tool: %v", err)
-		}
-
-		buf := new(bytes.Buffer)
-		stderr := new(bytes.Buffer)
-		cmd := exec.CommandContext(cfg.Context, tool, words...)
-		cmd.Dir = cfg.Dir
-		cmd.Env = cfg.Env
-		cmd.Stdin = bytes.NewReader(req)
-		cmd.Stdout = buf
-		cmd.Stderr = stderr
-
-		if err := cmd.Run(); err != nil {
-			return nil, fmt.Errorf("%v: %v: %s", tool, err, cmd.Stderr)
-		}
-		if len(stderr.Bytes()) != 0 && os.Getenv("GOPACKAGESPRINTDRIVERERRORS") != "" {
-			fmt.Fprintf(os.Stderr, "%s stderr: <<%s>>\n", cmdDebugStr(cmd), stderr)
-		}
-
-		var response driverResponse
-		if err := json.Unmarshal(buf.Bytes(), &response); err != nil {
-			return nil, err
-		}
-		return &response, nil
-	}
-}
diff --git a/vendor/golang.org/x/tools/go/packages/golist.go b/vendor/golang.org/x/tools/go/packages/golist.go
deleted file mode 100644
index ec417ba830..0000000000
--- a/vendor/golang.org/x/tools/go/packages/golist.go
+++ /dev/null
@@ -1,1096 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package packages
-
-import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"fmt"
-	"go/types"
-	exec "golang.org/x/sys/execabs"
-	"io/ioutil"
-	"log"
-	"os"
-	"path"
-	"path/filepath"
-	"reflect"
-	"sort"
-	"strconv"
-	"strings"
-	"sync"
-	"unicode"
-
-	"golang.org/x/tools/go/internal/packagesdriver"
-	"golang.org/x/tools/internal/gocommand"
-	"golang.org/x/xerrors"
-)
-
-// debug controls verbose logging.
-var debug, _ = strconv.ParseBool(os.Getenv("GOPACKAGESDEBUG"))
-
-// A goTooOldError reports that the go command
-// found by exec.LookPath is too old to use the new go list behavior.
-type goTooOldError struct {
-	error
-}
-
-// responseDeduper wraps a driverResponse, deduplicating its contents.
-type responseDeduper struct {
-	seenRoots    map[string]bool
-	seenPackages map[string]*Package
-	dr           *driverResponse
-}
-
-func newDeduper() *responseDeduper {
-	return &responseDeduper{
-		dr:           &driverResponse{},
-		seenRoots:    map[string]bool{},
-		seenPackages: map[string]*Package{},
-	}
-}
-
-// addAll fills in r with a driverResponse.
-func (r *responseDeduper) addAll(dr *driverResponse) {
-	for _, pkg := range dr.Packages {
-		r.addPackage(pkg)
-	}
-	for _, root := range dr.Roots {
-		r.addRoot(root)
-	}
-}
-
-func (r *responseDeduper) addPackage(p *Package) {
-	if r.seenPackages[p.ID] != nil {
-		return
-	}
-	r.seenPackages[p.ID] = p
-	r.dr.Packages = append(r.dr.Packages, p)
-}
-
-func (r *responseDeduper) addRoot(id string) {
-	if r.seenRoots[id] {
-		return
-	}
-	r.seenRoots[id] = true
-	r.dr.Roots = append(r.dr.Roots, id)
-}
-
-type golistState struct {
-	cfg *Config
-	ctx context.Context
-
-	envOnce    sync.Once
-	goEnvError error
-	goEnv      map[string]string
-
-	rootsOnce     sync.Once
-	rootDirsError error
-	rootDirs      map[string]string
-
-	goVersionOnce  sync.Once
-	goVersionError error
-	goVersion      int // The X in Go 1.X.
-
-	// vendorDirs caches the (non)existence of vendor directories.
-	vendorDirs map[string]bool
-}
-
-// getEnv returns Go environment variables. Only specific variables are
-// populated -- computing all of them is slow.
-func (state *golistState) getEnv() (map[string]string, error) {
-	state.envOnce.Do(func() {
-		var b *bytes.Buffer
-		b, state.goEnvError = state.invokeGo("env", "-json", "GOMOD", "GOPATH")
-		if state.goEnvError != nil {
-			return
-		}
-
-		state.goEnv = make(map[string]string)
-		decoder := json.NewDecoder(b)
-		if state.goEnvError = decoder.Decode(&state.goEnv); state.goEnvError != nil {
-			return
-		}
-	})
-	return state.goEnv, state.goEnvError
-}
-
-// mustGetEnv is a convenience function that can be used if getEnv has already succeeded.
-func (state *golistState) mustGetEnv() map[string]string {
-	env, err := state.getEnv()
-	if err != nil {
-		panic(fmt.Sprintf("mustGetEnv: %v", err))
-	}
-	return env
-}
-
-// goListDriver uses the go list command to interpret the patterns and produce
-// the build system package structure.
-// See driver for more details.
-func goListDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
-	// Make sure that any asynchronous go commands are killed when we return.
-	parentCtx := cfg.Context
-	if parentCtx == nil {
-		parentCtx = context.Background()
-	}
-	ctx, cancel := context.WithCancel(parentCtx)
-	defer cancel()
-
-	response := newDeduper()
-
-	state := &golistState{
-		cfg:        cfg,
-		ctx:        ctx,
-		vendorDirs: map[string]bool{},
-	}
-
-	// Fill in response.Sizes asynchronously if necessary.
-	var sizeserr error
-	var sizeswg sync.WaitGroup
-	if cfg.Mode&NeedTypesSizes != 0 || cfg.Mode&NeedTypes != 0 {
-		sizeswg.Add(1)
-		go func() {
-			var sizes types.Sizes
-			sizes, sizeserr = packagesdriver.GetSizesGolist(ctx, state.cfgInvocation(), cfg.gocmdRunner)
-			// types.SizesFor always returns nil or a *types.StdSizes.
-			response.dr.Sizes, _ = sizes.(*types.StdSizes)
-			sizeswg.Done()
-		}()
-	}
-
-	// Determine files requested in contains patterns
-	var containFiles []string
-	restPatterns := make([]string, 0, len(patterns))
-	// Extract file= and other [querytype]= patterns. Report an error if querytype
-	// doesn't exist.
-extractQueries:
-	for _, pattern := range patterns {
-		eqidx := strings.Index(pattern, "=")
-		if eqidx < 0 {
-			restPatterns = append(restPatterns, pattern)
-		} else {
-			query, value := pattern[:eqidx], pattern[eqidx+len("="):]
-			switch query {
-			case "file":
-				containFiles = append(containFiles, value)
-			case "pattern":
-				restPatterns = append(restPatterns, value)
-			case "": // not a reserved query
-				restPatterns = append(restPatterns, pattern)
-			default:
-				for _, rune := range query {
-					if rune < 'a' || rune > 'z' { // not a reserved query
-						restPatterns = append(restPatterns, pattern)
-						continue extractQueries
-					}
-				}
-				// Reject all other patterns containing "="
-				return nil, fmt.Errorf("invalid query type %q in query pattern %q", query, pattern)
-			}
-		}
-	}
-
-	// See if we have any patterns to pass through to go list. Zero initial
-	// patterns also requires a go list call, since it's the equivalent of
-	// ".".
-	if len(restPatterns) > 0 || len(patterns) == 0 {
-		dr, err := state.createDriverResponse(restPatterns...)
-		if err != nil {
-			return nil, err
-		}
-		response.addAll(dr)
-	}
-
-	if len(containFiles) != 0 {
-		if err := state.runContainsQueries(response, containFiles); err != nil {
-			return nil, err
-		}
-	}
-
-	// Only use go/packages' overlay processing if we're using a Go version
-	// below 1.16. Otherwise, go list handles it.
-	if goVersion, err := state.getGoVersion(); err == nil && goVersion < 16 {
-		modifiedPkgs, needPkgs, err := state.processGolistOverlay(response)
-		if err != nil {
-			return nil, err
-		}
-
-		var containsCandidates []string
-		if len(containFiles) > 0 {
-			containsCandidates = append(containsCandidates, modifiedPkgs...)
-			containsCandidates = append(containsCandidates, needPkgs...)
-		}
-		if err := state.addNeededOverlayPackages(response, needPkgs); err != nil {
-			return nil, err
-		}
-		// Check candidate packages for containFiles.
-		if len(containFiles) > 0 {
-			for _, id := range containsCandidates {
-				pkg, ok := response.seenPackages[id]
-				if !ok {
-					response.addPackage(&Package{
-						ID: id,
-						Errors: []Error{{
-							Kind: ListError,
-							Msg:  fmt.Sprintf("package %s expected but not seen", id),
-						}},
-					})
-					continue
-				}
-				for _, f := range containFiles {
-					for _, g := range pkg.GoFiles {
-						if sameFile(f, g) {
-							response.addRoot(id)
-						}
-					}
-				}
-			}
-		}
-		// Add root for any package that matches a pattern. This applies only to
-		// packages that are modified by overlays, since they are not added as
-		// roots automatically.
-		for _, pattern := range restPatterns {
-			match := matchPattern(pattern)
-			for _, pkgID := range modifiedPkgs {
-				pkg, ok := response.seenPackages[pkgID]
-				if !ok {
-					continue
-				}
-				if match(pkg.PkgPath) {
-					response.addRoot(pkg.ID)
-				}
-			}
-		}
-	}
-
-	sizeswg.Wait()
-	if sizeserr != nil {
-		return nil, sizeserr
-	}
-	return response.dr, nil
-}
-
-func (state *golistState) addNeededOverlayPackages(response *responseDeduper, pkgs []string) error {
-	if len(pkgs) == 0 {
-		return nil
-	}
-	dr, err := state.createDriverResponse(pkgs...)
-	if err != nil {
-		return err
-	}
-	for _, pkg := range dr.Packages {
-		response.addPackage(pkg)
-	}
-	_, needPkgs, err := state.processGolistOverlay(response)
-	if err != nil {
-		return err
-	}
-	return state.addNeededOverlayPackages(response, needPkgs)
-}
-
-func (state *golistState) runContainsQueries(response *responseDeduper, queries []string) error {
-	for _, query := range queries {
-		// TODO(matloob): Do only one query per directory.
-		fdir := filepath.Dir(query)
-		// Pass absolute path of directory to go list so that it knows to treat it as a directory,
-		// not a package path.
-		pattern, err := filepath.Abs(fdir)
-		if err != nil {
-			return fmt.Errorf("could not determine absolute path of file= query path %q: %v", query, err)
-		}
-		dirResponse, err := state.createDriverResponse(pattern)
-
-		// If there was an error loading the package, or the package is returned
-		// with errors, try to load the file as an ad-hoc package.
-		// Usually the error will appear in a returned package, but may not if we're
-		// in module mode and the ad-hoc is located outside a module.
-		if err != nil || len(dirResponse.Packages) == 1 && len(dirResponse.Packages[0].GoFiles) == 0 &&
-			len(dirResponse.Packages[0].Errors) == 1 {
-			var queryErr error
-			if dirResponse, queryErr = state.adhocPackage(pattern, query); queryErr != nil {
-				return err // return the original error
-			}
-		}
-		isRoot := make(map[string]bool, len(dirResponse.Roots))
-		for _, root := range dirResponse.Roots {
-			isRoot[root] = true
-		}
-		for _, pkg := range dirResponse.Packages {
-			// Add any new packages to the main set
-			// We don't bother to filter packages that will be dropped by the changes of roots,
-			// that will happen anyway during graph construction outside this function.
-			// Over-reporting packages is not a problem.
-			response.addPackage(pkg)
-			// if the package was not a root one, it cannot have the file
-			if !isRoot[pkg.ID] {
-				continue
-			}
-			for _, pkgFile := range pkg.GoFiles {
-				if filepath.Base(query) == filepath.Base(pkgFile) {
-					response.addRoot(pkg.ID)
-					break
-				}
-			}
-		}
-	}
-	return nil
-}
-
-// adhocPackage attempts to load or construct an ad-hoc package for a given
-// query, if the original call to the driver produced inadequate results.
-func (state *golistState) adhocPackage(pattern, query string) (*driverResponse, error) {
-	response, err := state.createDriverResponse(query)
-	if err != nil {
-		return nil, err
-	}
-	// If we get nothing back from `go list`,
-	// try to make this file into its own ad-hoc package.
-	// TODO(rstambler): Should this check against the original response?
-	if len(response.Packages) == 0 {
-		response.Packages = append(response.Packages, &Package{
-			ID:              "command-line-arguments",
-			PkgPath:         query,
-			GoFiles:         []string{query},
-			CompiledGoFiles: []string{query},
-			Imports:         make(map[string]*Package),
-		})
-		response.Roots = append(response.Roots, "command-line-arguments")
-	}
-	// Handle special cases.
-	if len(response.Packages) == 1 {
-		// golang/go#33482: If this is a file= query for ad-hoc packages where
-		// the file only exists on an overlay, and exists outside of a module,
-		// add the file to the package and remove the errors.
-		if response.Packages[0].ID == "command-line-arguments" ||
-			filepath.ToSlash(response.Packages[0].PkgPath) == filepath.ToSlash(query) {
-			if len(response.Packages[0].GoFiles) == 0 {
-				filename := filepath.Join(pattern, filepath.Base(query)) // avoid recomputing abspath
-				// TODO(matloob): check if the file is outside of a root dir?
-				for path := range state.cfg.Overlay {
-					if path == filename {
-						response.Packages[0].Errors = nil
-						response.Packages[0].GoFiles = []string{path}
-						response.Packages[0].CompiledGoFiles = []string{path}
-					}
-				}
-			}
-		}
-	}
-	return response, nil
-}
-
-// Fields must match go list;
-// see $GOROOT/src/cmd/go/internal/load/pkg.go.
-type jsonPackage struct {
-	ImportPath        string
-	Dir               string
-	Name              string
-	Export            string
-	GoFiles           []string
-	CompiledGoFiles   []string
-	IgnoredGoFiles    []string
-	IgnoredOtherFiles []string
-	CFiles            []string
-	CgoFiles          []string
-	CXXFiles          []string
-	MFiles            []string
-	HFiles            []string
-	FFiles            []string
-	SFiles            []string
-	SwigFiles         []string
-	SwigCXXFiles      []string
-	SysoFiles         []string
-	Imports           []string
-	ImportMap         map[string]string
-	Deps              []string
-	Module            *Module
-	TestGoFiles       []string
-	TestImports       []string
-	XTestGoFiles      []string
-	XTestImports      []string
-	ForTest           string // q in a "p [q.test]" package, else ""
-	DepOnly           bool
-
-	Error *jsonPackageError
-}
-
-type jsonPackageError struct {
-	ImportStack []string
-	Pos         string
-	Err         string
-}
-
-func otherFiles(p *jsonPackage) [][]string {
-	return [][]string{p.CFiles, p.CXXFiles, p.MFiles, p.HFiles, p.FFiles, p.SFiles, p.SwigFiles, p.SwigCXXFiles, p.SysoFiles}
-}
-
-// createDriverResponse uses the "go list" command to expand the pattern
-// words and return a response for the specified packages.
-func (state *golistState) createDriverResponse(words ...string) (*driverResponse, error) {
-	// go list uses the following identifiers in ImportPath and Imports:
-	//
-	// 	"p"			-- importable package or main (command)
-	// 	"q.test"		-- q's test executable
-	// 	"p [q.test]"		-- variant of p as built for q's test executable
-	// 	"q_test [q.test]"	-- q's external test package
-	//
-	// The packages p that are built differently for a test q.test
-	// are q itself, plus any helpers used by the external test q_test,
-	// typically including "testing" and all its dependencies.
-
-	// Run "go list" for complete
-	// information on the specified packages.
-	buf, err := state.invokeGo("list", golistargs(state.cfg, words)...)
-	if err != nil {
-		return nil, err
-	}
-	seen := make(map[string]*jsonPackage)
-	pkgs := make(map[string]*Package)
-	additionalErrors := make(map[string][]Error)
-	// Decode the JSON and convert it to Package form.
-	var response driverResponse
-	for dec := json.NewDecoder(buf); dec.More(); {
-		p := new(jsonPackage)
-		if err := dec.Decode(p); err != nil {
-			return nil, fmt.Errorf("JSON decoding failed: %v", err)
-		}
-
-		if p.ImportPath == "" {
-			// The documentation for go list says that “[e]rroneous packages will have
-			// a non-empty ImportPath”. If for some reason it comes back empty, we
-			// prefer to error out rather than silently discarding data or handing
-			// back a package without any way to refer to it.
-			if p.Error != nil {
-				return nil, Error{
-					Pos: p.Error.Pos,
-					Msg: p.Error.Err,
-				}
-			}
-			return nil, fmt.Errorf("package missing import path: %+v", p)
-		}
-
-		// Work around https://golang.org/issue/33157:
-		// go list -e, when given an absolute path, will find the package contained at
-		// that directory. But when no package exists there, it will return a fake package
-		// with an error and the ImportPath set to the absolute path provided to go list.
-		// Try to convert that absolute path to what its package path would be if it's
-		// contained in a known module or GOPATH entry. This will allow the package to be
-		// properly "reclaimed" when overlays are processed.
-		if filepath.IsAbs(p.ImportPath) && p.Error != nil {
-			pkgPath, ok, err := state.getPkgPath(p.ImportPath)
-			if err != nil {
-				return nil, err
-			}
-			if ok {
-				p.ImportPath = pkgPath
-			}
-		}
-
-		if old, found := seen[p.ImportPath]; found {
-			// If one version of the package has an error, and the other doesn't, assume
-			// that this is a case where go list is reporting a fake dependency variant
-			// of the imported package: When a package tries to invalidly import another
-			// package, go list emits a variant of the imported package (with the same
-			// import path, but with an error on it, and the package will have a
-			// DepError set on it). An example of when this can happen is for imports of
-			// main packages: main packages can not be imported, but they may be
-			// separately matched and listed by another pattern.
-			// See golang.org/issue/36188 for more details.
-
-			// The plan is that eventually, hopefully in Go 1.15, the error will be
-			// reported on the importing package rather than the duplicate "fake"
-			// version of the imported package. Once all supported versions of Go
-			// have the new behavior this logic can be deleted.
-			// TODO(matloob): delete the workaround logic once all supported versions of
-			// Go return the errors on the proper package.
-
-			// There should be exactly one version of a package that doesn't have an
-			// error.
-			if old.Error == nil && p.Error == nil {
-				if !reflect.DeepEqual(p, old) {
-					return nil, fmt.Errorf("internal error: go list gives conflicting information for package %v", p.ImportPath)
-				}
-				continue
-			}
-
-			// Determine if this package's error needs to be bubbled up.
-			// This is a hack, and we expect for go list to eventually set the error
-			// on the package.
-			if old.Error != nil {
-				var errkind string
-				if strings.Contains(old.Error.Err, "not an importable package") {
-					errkind = "not an importable package"
-				} else if strings.Contains(old.Error.Err, "use of internal package") && strings.Contains(old.Error.Err, "not allowed") {
-					errkind = "use of internal package not allowed"
-				}
-				if errkind != "" {
-					if len(old.Error.ImportStack) < 1 {
-						return nil, fmt.Errorf(`internal error: go list gave a %q error with empty import stack`, errkind)
-					}
-					importingPkg := old.Error.ImportStack[len(old.Error.ImportStack)-1]
-					if importingPkg == old.ImportPath {
-						// Using an older version of Go which put this package itself on top of import
-						// stack, instead of the importer. Look for importer in second from top
-						// position.
-						if len(old.Error.ImportStack) < 2 {
-							return nil, fmt.Errorf(`internal error: go list gave a %q error with an import stack without importing package`, errkind)
-						}
-						importingPkg = old.Error.ImportStack[len(old.Error.ImportStack)-2]
-					}
-					additionalErrors[importingPkg] = append(additionalErrors[importingPkg], Error{
-						Pos:  old.Error.Pos,
-						Msg:  old.Error.Err,
-						Kind: ListError,
-					})
-				}
-			}
-
-			// Make sure that if there's a version of the package without an error,
-			// that's the one reported to the user.
-			if old.Error == nil {
-				continue
-			}
-
-			// This package will replace the old one at the end of the loop.
-		}
-		seen[p.ImportPath] = p
-
-		pkg := &Package{
-			Name:            p.Name,
-			ID:              p.ImportPath,
-			GoFiles:         absJoin(p.Dir, p.GoFiles, p.CgoFiles),
-			CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles),
-			OtherFiles:      absJoin(p.Dir, otherFiles(p)...),
-			IgnoredFiles:    absJoin(p.Dir, p.IgnoredGoFiles, p.IgnoredOtherFiles),
-			forTest:         p.ForTest,
-			Module:          p.Module,
-		}
-
-		if (state.cfg.Mode&typecheckCgo) != 0 && len(p.CgoFiles) != 0 {
-			if len(p.CompiledGoFiles) > len(p.GoFiles) {
-				// We need the cgo definitions, which are in the first
-				// CompiledGoFile after the non-cgo ones. This is a hack but there
-				// isn't currently a better way to find it. We also need the pure
-				// Go files and unprocessed cgo files, all of which are already
-				// in pkg.GoFiles.
-				cgoTypes := p.CompiledGoFiles[len(p.GoFiles)]
-				pkg.CompiledGoFiles = append([]string{cgoTypes}, pkg.GoFiles...)
-			} else {
-				// golang/go#38990: go list silently fails to do cgo processing
-				pkg.CompiledGoFiles = nil
-				pkg.Errors = append(pkg.Errors, Error{
-					Msg:  "go list failed to return CompiledGoFiles; https://golang.org/issue/38990?",
-					Kind: ListError,
-				})
-			}
-		}
-
-		// Work around https://golang.org/issue/28749:
-		// cmd/go puts assembly, C, and C++ files in CompiledGoFiles.
-		// Filter out any elements of CompiledGoFiles that are also in OtherFiles.
-		// We have to keep this workaround in place until go1.12 is a distant memory.
-		if len(pkg.OtherFiles) > 0 {
-			other := make(map[string]bool, len(pkg.OtherFiles))
-			for _, f := range pkg.OtherFiles {
-				other[f] = true
-			}
-
-			out := pkg.CompiledGoFiles[:0]
-			for _, f := range pkg.CompiledGoFiles {
-				if other[f] {
-					continue
-				}
-				out = append(out, f)
-			}
-			pkg.CompiledGoFiles = out
-		}
-
-		// Extract the PkgPath from the package's ID.
-		if i := strings.IndexByte(pkg.ID, ' '); i >= 0 {
-			pkg.PkgPath = pkg.ID[:i]
-		} else {
-			pkg.PkgPath = pkg.ID
-		}
-
-		if pkg.PkgPath == "unsafe" {
-			pkg.GoFiles = nil // ignore fake unsafe.go file
-		}
-
-		// Assume go list emits only absolute paths for Dir.
-		if p.Dir != "" && !filepath.IsAbs(p.Dir) {
-			log.Fatalf("internal error: go list returned non-absolute Package.Dir: %s", p.Dir)
-		}
-
-		if p.Export != "" && !filepath.IsAbs(p.Export) {
-			pkg.ExportFile = filepath.Join(p.Dir, p.Export)
-		} else {
-			pkg.ExportFile = p.Export
-		}
-
-		// imports
-		//
-		// Imports contains the IDs of all imported packages.
-		// ImportsMap records (path, ID) only where they differ.
-		ids := make(map[string]bool)
-		for _, id := range p.Imports {
-			ids[id] = true
-		}
-		pkg.Imports = make(map[string]*Package)
-		for path, id := range p.ImportMap {
-			pkg.Imports[path] = &Package{ID: id} // non-identity import
-			delete(ids, id)
-		}
-		for id := range ids {
-			if id == "C" {
-				continue
-			}
-
-			pkg.Imports[id] = &Package{ID: id} // identity import
-		}
-		if !p.DepOnly {
-			response.Roots = append(response.Roots, pkg.ID)
-		}
-
-		// Work around for pre-go.1.11 versions of go list.
-		// TODO(matloob): they should be handled by the fallback.
-		// Can we delete this?
-		if len(pkg.CompiledGoFiles) == 0 {
-			pkg.CompiledGoFiles = pkg.GoFiles
-		}
-
-		// Temporary work-around for golang/go#39986. Parse filenames out of
-		// error messages. This happens if there are unrecoverable syntax
-		// errors in the source, so we can't match on a specific error message.
-		if err := p.Error; err != nil && state.shouldAddFilenameFromError(p) {
-			addFilenameFromPos := func(pos string) bool {
-				split := strings.Split(pos, ":")
-				if len(split) < 1 {
-					return false
-				}
-				filename := strings.TrimSpace(split[0])
-				if filename == "" {
-					return false
-				}
-				if !filepath.IsAbs(filename) {
-					filename = filepath.Join(state.cfg.Dir, filename)
-				}
-				info, _ := os.Stat(filename)
-				if info == nil {
-					return false
-				}
-				pkg.CompiledGoFiles = append(pkg.CompiledGoFiles, filename)
-				pkg.GoFiles = append(pkg.GoFiles, filename)
-				return true
-			}
-			found := addFilenameFromPos(err.Pos)
-			// In some cases, go list only reports the error position in the
-			// error text, not the error position. One such case is when the
-			// file's package name is a keyword (see golang.org/issue/39763).
-			if !found {
-				addFilenameFromPos(err.Err)
-			}
-		}
-
-		if p.Error != nil {
-			msg := strings.TrimSpace(p.Error.Err) // Trim to work around golang.org/issue/32363.
-			// Address golang.org/issue/35964 by appending import stack to error message.
-			if msg == "import cycle not allowed" && len(p.Error.ImportStack) != 0 {
-				msg += fmt.Sprintf(": import stack: %v", p.Error.ImportStack)
-			}
-			pkg.Errors = append(pkg.Errors, Error{
-				Pos:  p.Error.Pos,
-				Msg:  msg,
-				Kind: ListError,
-			})
-		}
-
-		pkgs[pkg.ID] = pkg
-	}
-
-	for id, errs := range additionalErrors {
-		if p, ok := pkgs[id]; ok {
-			p.Errors = append(p.Errors, errs...)
-		}
-	}
-	for _, pkg := range pkgs {
-		response.Packages = append(response.Packages, pkg)
-	}
-	sort.Slice(response.Packages, func(i, j int) bool { return response.Packages[i].ID < response.Packages[j].ID })
-
-	return &response, nil
-}
-
-func (state *golistState) shouldAddFilenameFromError(p *jsonPackage) bool {
-	if len(p.GoFiles) > 0 || len(p.CompiledGoFiles) > 0 {
-		return false
-	}
-
-	goV, err := state.getGoVersion()
-	if err != nil {
-		return false
-	}
-
-	// On Go 1.14 and earlier, only add filenames from errors if the import stack is empty.
-	// The import stack behaves differently for these versions than newer Go versions.
-	if goV < 15 {
-		return len(p.Error.ImportStack) == 0
-	}
-
-	// On Go 1.15 and later, only parse filenames out of error if there's no import stack,
-	// or the current package is at the top of the import stack. This is not guaranteed
-	// to work perfectly, but should avoid some cases where files in errors don't belong to this
-	// package.
-	return len(p.Error.ImportStack) == 0 || p.Error.ImportStack[len(p.Error.ImportStack)-1] == p.ImportPath
-}
-
-func (state *golistState) getGoVersion() (int, error) {
-	state.goVersionOnce.Do(func() {
-		state.goVersion, state.goVersionError = gocommand.GoVersion(state.ctx, state.cfgInvocation(), state.cfg.gocmdRunner)
-	})
-	return state.goVersion, state.goVersionError
-}
-
-// getPkgPath finds the package path of a directory if it's relative to a root
-// directory.
-func (state *golistState) getPkgPath(dir string) (string, bool, error) {
-	absDir, err := filepath.Abs(dir)
-	if err != nil {
-		return "", false, err
-	}
-	roots, err := state.determineRootDirs()
-	if err != nil {
-		return "", false, err
-	}
-
-	for rdir, rpath := range roots {
-		// Make sure that the directory is in the module,
-		// to avoid creating a path relative to another module.
-		if !strings.HasPrefix(absDir, rdir) {
-			continue
-		}
-		// TODO(matloob): This doesn't properly handle symlinks.
-		r, err := filepath.Rel(rdir, dir)
-		if err != nil {
-			continue
-		}
-		if rpath != "" {
-			// We choose only one root even though the directory even it can belong in multiple modules
-			// or GOPATH entries. This is okay because we only need to work with absolute dirs when a
-			// file is missing from disk, for instance when gopls calls go/packages in an overlay.
-			// Once the file is saved, gopls, or the next invocation of the tool will get the correct
-			// result straight from golist.
-			// TODO(matloob): Implement module tiebreaking?
-			return path.Join(rpath, filepath.ToSlash(r)), true, nil
-		}
-		return filepath.ToSlash(r), true, nil
-	}
-	return "", false, nil
-}
-
-// absJoin absolutizes and flattens the lists of files.
-func absJoin(dir string, fileses ...[]string) (res []string) {
-	for _, files := range fileses {
-		for _, file := range files {
-			if !filepath.IsAbs(file) {
-				file = filepath.Join(dir, file)
-			}
-			res = append(res, file)
-		}
-	}
-	return res
-}
-
-func golistargs(cfg *Config, words []string) []string {
-	const findFlags = NeedImports | NeedTypes | NeedSyntax | NeedTypesInfo
-	fullargs := []string{
-		"-e", "-json",
-		fmt.Sprintf("-compiled=%t", cfg.Mode&(NeedCompiledGoFiles|NeedSyntax|NeedTypes|NeedTypesInfo|NeedTypesSizes) != 0),
-		fmt.Sprintf("-test=%t", cfg.Tests),
-		fmt.Sprintf("-export=%t", usesExportData(cfg)),
-		fmt.Sprintf("-deps=%t", cfg.Mode&NeedImports != 0),
-		// go list doesn't let you pass -test and -find together,
-		// probably because you'd just get the TestMain.
-		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0),
-	}
-	fullargs = append(fullargs, cfg.BuildFlags...)
-	fullargs = append(fullargs, "--")
-	fullargs = append(fullargs, words...)
-	return fullargs
-}
-
-// cfgInvocation returns an Invocation that reflects cfg's settings.
-func (state *golistState) cfgInvocation() gocommand.Invocation {
-	cfg := state.cfg
-	return gocommand.Invocation{
-		BuildFlags: cfg.BuildFlags,
-		ModFile:    cfg.modFile,
-		ModFlag:    cfg.modFlag,
-		CleanEnv:   cfg.Env != nil,
-		Env:        cfg.Env,
-		Logf:       cfg.Logf,
-		WorkingDir: cfg.Dir,
-	}
-}
-
-// invokeGo returns the stdout of a go command invocation.
-func (state *golistState) invokeGo(verb string, args ...string) (*bytes.Buffer, error) {
-	cfg := state.cfg
-
-	inv := state.cfgInvocation()
-
-	// For Go versions 1.16 and above, `go list` accepts overlays directly via
-	// the -overlay flag. Set it, if it's available.
-	//
-	// The check for "list" is not necessarily required, but we should avoid
-	// getting the go version if possible.
-	if verb == "list" {
-		goVersion, err := state.getGoVersion()
-		if err != nil {
-			return nil, err
-		}
-		if goVersion >= 16 {
-			filename, cleanup, err := state.writeOverlays()
-			if err != nil {
-				return nil, err
-			}
-			defer cleanup()
-			inv.Overlay = filename
-		}
-	}
-	inv.Verb = verb
-	inv.Args = args
-	gocmdRunner := cfg.gocmdRunner
-	if gocmdRunner == nil {
-		gocmdRunner = &gocommand.Runner{}
-	}
-	stdout, stderr, _, err := gocmdRunner.RunRaw(cfg.Context, inv)
-	if err != nil {
-		// Check for 'go' executable not being found.
-		if ee, ok := err.(*exec.Error); ok && ee.Err == exec.ErrNotFound {
-			return nil, fmt.Errorf("'go list' driver requires 'go', but %s", exec.ErrNotFound)
-		}
-
-		exitErr, ok := err.(*exec.ExitError)
-		if !ok {
-			// Catastrophic error:
-			// - context cancellation
-			return nil, xerrors.Errorf("couldn't run 'go': %w", err)
-		}
-
-		// Old go version?
-		if strings.Contains(stderr.String(), "flag provided but not defined") {
-			return nil, goTooOldError{fmt.Errorf("unsupported version of go: %s: %s", exitErr, stderr)}
-		}
-
-		// Related to #24854
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "unexpected directory layout") {
-			return nil, fmt.Errorf("%s", stderr.String())
-		}
-
-		// Is there an error running the C compiler in cgo? This will be reported in the "Error" field
-		// and should be suppressed by go list -e.
-		//
-		// This condition is not perfect yet because the error message can include other error messages than runtime/cgo.
-		isPkgPathRune := func(r rune) bool {
-			// From https://golang.org/ref/spec#Import_declarations:
-			//    Implementation restriction: A compiler may restrict ImportPaths to non-empty strings
-			//    using only characters belonging to Unicode's L, M, N, P, and S general categories
-			//    (the Graphic characters without spaces) and may also exclude the
-			//    characters !"#$%&'()*,:;<=>?[\]^`{|} and the Unicode replacement character U+FFFD.
-			return unicode.IsOneOf([]*unicode.RangeTable{unicode.L, unicode.M, unicode.N, unicode.P, unicode.S}, r) &&
-				!strings.ContainsRune("!\"#$%&'()*,:;<=>?[\\]^`{|}\uFFFD", r)
-		}
-		// golang/go#36770: Handle case where cmd/go prints module download messages before the error.
-		msg := stderr.String()
-		for strings.HasPrefix(msg, "go: downloading") {
-			msg = msg[strings.IndexRune(msg, '\n')+1:]
-		}
-		if len(stderr.String()) > 0 && strings.HasPrefix(stderr.String(), "# ") {
-			msg := msg[len("# "):]
-			if strings.HasPrefix(strings.TrimLeftFunc(msg, isPkgPathRune), "\n") {
-				return stdout, nil
-			}
-			// Treat pkg-config errors as a special case (golang.org/issue/36770).
-			if strings.HasPrefix(msg, "pkg-config") {
-				return stdout, nil
-			}
-		}
-
-		// This error only appears in stderr. See golang.org/cl/166398 for a fix in go list to show
-		// the error in the Err section of stdout in case -e option is provided.
-		// This fix is provided for backwards compatibility.
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "named files must be .go files") {
-			output := fmt.Sprintf(`{"ImportPath": "command-line-arguments","Incomplete": true,"Error": {"Pos": "","Err": %q}}`,
-				strings.Trim(stderr.String(), "\n"))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Similar to the previous error, but currently lacks a fix in Go.
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "named files must all be in one directory") {
-			output := fmt.Sprintf(`{"ImportPath": "command-line-arguments","Incomplete": true,"Error": {"Pos": "","Err": %q}}`,
-				strings.Trim(stderr.String(), "\n"))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Backwards compatibility for Go 1.11 because 1.12 and 1.13 put the directory in the ImportPath.
-		// If the package doesn't exist, put the absolute path of the directory into the error message,
-		// as Go 1.13 list does.
-		const noSuchDirectory = "no such directory"
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), noSuchDirectory) {
-			errstr := stderr.String()
-			abspath := strings.TrimSpace(errstr[strings.Index(errstr, noSuchDirectory)+len(noSuchDirectory):])
-			output := fmt.Sprintf(`{"ImportPath": %q,"Incomplete": true,"Error": {"Pos": "","Err": %q}}`,
-				abspath, strings.Trim(stderr.String(), "\n"))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Workaround for #29280: go list -e has incorrect behavior when an ad-hoc package doesn't exist.
-		// Note that the error message we look for in this case is different that the one looked for above.
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "no such file or directory") {
-			output := fmt.Sprintf(`{"ImportPath": "command-line-arguments","Incomplete": true,"Error": {"Pos": "","Err": %q}}`,
-				strings.Trim(stderr.String(), "\n"))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Workaround for #34273. go list -e with GO111MODULE=on has incorrect behavior when listing a
-		// directory outside any module.
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "outside available modules") {
-			output := fmt.Sprintf(`{"ImportPath": %q,"Incomplete": true,"Error": {"Pos": "","Err": %q}}`,
-				// TODO(matloob): command-line-arguments isn't correct here.
-				"command-line-arguments", strings.Trim(stderr.String(), "\n"))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Another variation of the previous error
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "outside module root") {
-			output := fmt.Sprintf(`{"ImportPath": %q,"Incomplete": true,"Error": {"Pos": "","Err": %q}}`,
-				// TODO(matloob): command-line-arguments isn't correct here.
-				"command-line-arguments", strings.Trim(stderr.String(), "\n"))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Workaround for an instance of golang.org/issue/26755: go list -e  will return a non-zero exit
-		// status if there's a dependency on a package that doesn't exist. But it should return
-		// a zero exit status and set an error on that package.
-		if len(stderr.String()) > 0 && strings.Contains(stderr.String(), "no Go files in") {
-			// Don't clobber stdout if `go list` actually returned something.
-			if len(stdout.String()) > 0 {
-				return stdout, nil
-			}
-			// try to extract package name from string
-			stderrStr := stderr.String()
-			var importPath string
-			colon := strings.Index(stderrStr, ":")
-			if colon > 0 && strings.HasPrefix(stderrStr, "go build ") {
-				importPath = stderrStr[len("go build "):colon]
-			}
-			output := fmt.Sprintf(`{"ImportPath": %q,"Incomplete": true,"Error": {"Pos": "","Err": %q}}`,
-				importPath, strings.Trim(stderrStr, "\n"))
-			return bytes.NewBufferString(output), nil
-		}
-
-		// Export mode entails a build.
-		// If that build fails, errors appear on stderr
-		// (despite the -e flag) and the Export field is blank.
-		// Do not fail in that case.
-		// The same is true if an ad-hoc package given to go list doesn't exist.
-		// TODO(matloob): Remove these once we can depend on go list to exit with a zero status with -e even when
-		// packages don't exist or a build fails.
-		if !usesExportData(cfg) && !containsGoFile(args) {
-			return nil, fmt.Errorf("go %v: %s: %s", args, exitErr, stderr)
-		}
-	}
-	return stdout, nil
-}
-
-// OverlayJSON is the format overlay files are expected to be in.
-// The Replace map maps from overlaid paths to replacement paths:
-// the Go command will forward all reads trying to open
-// each overlaid path to its replacement path, or consider the overlaid
-// path not to exist if the replacement path is empty.
-//
-// From golang/go#39958.
-type OverlayJSON struct {
-	Replace map[string]string `json:"replace,omitempty"`
-}
-
-// writeOverlays writes out files for go list's -overlay flag, as described
-// above.
-func (state *golistState) writeOverlays() (filename string, cleanup func(), err error) {
-	// Do nothing if there are no overlays in the config.
-	if len(state.cfg.Overlay) == 0 {
-		return "", func() {}, nil
-	}
-	dir, err := ioutil.TempDir("", "gopackages-*")
-	if err != nil {
-		return "", nil, err
-	}
-	// The caller must clean up this directory, unless this function returns an
-	// error.
-	cleanup = func() {
-		os.RemoveAll(dir)
-	}
-	defer func() {
-		if err != nil {
-			cleanup()
-		}
-	}()
-	overlays := map[string]string{}
-	for k, v := range state.cfg.Overlay {
-		// Create a unique filename for the overlaid files, to avoid
-		// creating nested directories.
-		noSeparator := strings.Join(strings.Split(filepath.ToSlash(k), "/"), "")
-		f, err := ioutil.TempFile(dir, fmt.Sprintf("*-%s", noSeparator))
-		if err != nil {
-			return "", func() {}, err
-		}
-		if _, err := f.Write(v); err != nil {
-			return "", func() {}, err
-		}
-		if err := f.Close(); err != nil {
-			return "", func() {}, err
-		}
-		overlays[k] = f.Name()
-	}
-	b, err := json.Marshal(OverlayJSON{Replace: overlays})
-	if err != nil {
-		return "", func() {}, err
-	}
-	// Write out the overlay file that contains the filepath mappings.
-	filename = filepath.Join(dir, "overlay.json")
-	if err := ioutil.WriteFile(filename, b, 0665); err != nil {
-		return "", func() {}, err
-	}
-	return filename, cleanup, nil
-}
-
-func containsGoFile(s []string) bool {
-	for _, f := range s {
-		if strings.HasSuffix(f, ".go") {
-			return true
-		}
-	}
-	return false
-}
-
-func cmdDebugStr(cmd *exec.Cmd) string {
-	env := make(map[string]string)
-	for _, kv := range cmd.Env {
-		split := strings.SplitN(kv, "=", 2)
-		k, v := split[0], split[1]
-		env[k] = v
-	}
-
-	var args []string
-	for _, arg := range cmd.Args {
-		quoted := strconv.Quote(arg)
-		if quoted[1:len(quoted)-1] != arg || strings.Contains(arg, " ") {
-			args = append(args, quoted)
-		} else {
-			args = append(args, arg)
-		}
-	}
-	return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v GOPROXY=%v PWD=%v %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["GOPROXY"], env["PWD"], strings.Join(args, " "))
-}
diff --git a/vendor/golang.org/x/tools/go/packages/golist_overlay.go b/vendor/golang.org/x/tools/go/packages/golist_overlay.go
deleted file mode 100644
index 9576b472f9..0000000000
--- a/vendor/golang.org/x/tools/go/packages/golist_overlay.go
+++ /dev/null
@@ -1,575 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package packages
-
-import (
-	"encoding/json"
-	"fmt"
-	"go/parser"
-	"go/token"
-	"os"
-	"path/filepath"
-	"regexp"
-	"sort"
-	"strconv"
-	"strings"
-
-	"golang.org/x/tools/internal/gocommand"
-)
-
-// processGolistOverlay provides rudimentary support for adding
-// files that don't exist on disk to an overlay. The results can be
-// sometimes incorrect.
-// TODO(matloob): Handle unsupported cases, including the following:
-// - determining the correct package to add given a new import path
-func (state *golistState) processGolistOverlay(response *responseDeduper) (modifiedPkgs, needPkgs []string, err error) {
-	havePkgs := make(map[string]string) // importPath -> non-test package ID
-	needPkgsSet := make(map[string]bool)
-	modifiedPkgsSet := make(map[string]bool)
-
-	pkgOfDir := make(map[string][]*Package)
-	for _, pkg := range response.dr.Packages {
-		// This is an approximation of import path to id. This can be
-		// wrong for tests, vendored packages, and a number of other cases.
-		havePkgs[pkg.PkgPath] = pkg.ID
-		dir, err := commonDir(pkg.GoFiles)
-		if err != nil {
-			return nil, nil, err
-		}
-		if dir != "" {
-			pkgOfDir[dir] = append(pkgOfDir[dir], pkg)
-		}
-	}
-
-	// If no new imports are added, it is safe to avoid loading any needPkgs.
-	// Otherwise, it's hard to tell which package is actually being loaded
-	// (due to vendoring) and whether any modified package will show up
-	// in the transitive set of dependencies (because new imports are added,
-	// potentially modifying the transitive set of dependencies).
-	var overlayAddsImports bool
-
-	// If both a package and its test package are created by the overlay, we
-	// need the real package first. Process all non-test files before test
-	// files, and make the whole process deterministic while we're at it.
-	var overlayFiles []string
-	for opath := range state.cfg.Overlay {
-		overlayFiles = append(overlayFiles, opath)
-	}
-	sort.Slice(overlayFiles, func(i, j int) bool {
-		iTest := strings.HasSuffix(overlayFiles[i], "_test.go")
-		jTest := strings.HasSuffix(overlayFiles[j], "_test.go")
-		if iTest != jTest {
-			return !iTest // non-tests are before tests.
-		}
-		return overlayFiles[i] < overlayFiles[j]
-	})
-	for _, opath := range overlayFiles {
-		contents := state.cfg.Overlay[opath]
-		base := filepath.Base(opath)
-		dir := filepath.Dir(opath)
-		var pkg *Package           // if opath belongs to both a package and its test variant, this will be the test variant
-		var testVariantOf *Package // if opath is a test file, this is the package it is testing
-		var fileExists bool
-		isTestFile := strings.HasSuffix(opath, "_test.go")
-		pkgName, ok := extractPackageName(opath, contents)
-		if !ok {
-			// Don't bother adding a file that doesn't even have a parsable package statement
-			// to the overlay.
-			continue
-		}
-		// If all the overlay files belong to a different package, change the
-		// package name to that package.
-		maybeFixPackageName(pkgName, isTestFile, pkgOfDir[dir])
-	nextPackage:
-		for _, p := range response.dr.Packages {
-			if pkgName != p.Name && p.ID != "command-line-arguments" {
-				continue
-			}
-			for _, f := range p.GoFiles {
-				if !sameFile(filepath.Dir(f), dir) {
-					continue
-				}
-				// Make sure to capture information on the package's test variant, if needed.
-				if isTestFile && !hasTestFiles(p) {
-					// TODO(matloob): Are there packages other than the 'production' variant
-					// of a package that this can match? This shouldn't match the test main package
-					// because the file is generated in another directory.
-					testVariantOf = p
-					continue nextPackage
-				} else if !isTestFile && hasTestFiles(p) {
-					// We're examining a test variant, but the overlaid file is
-					// a non-test file. Because the overlay implementation
-					// (currently) only adds a file to one package, skip this
-					// package, so that we can add the file to the production
-					// variant of the package. (https://golang.org/issue/36857
-					// tracks handling overlays on both the production and test
-					// variant of a package).
-					continue nextPackage
-				}
-				if pkg != nil && p != pkg && pkg.PkgPath == p.PkgPath {
-					// We have already seen the production version of the
-					// for which p is a test variant.
-					if hasTestFiles(p) {
-						testVariantOf = pkg
-					}
-				}
-				pkg = p
-				if filepath.Base(f) == base {
-					fileExists = true
-				}
-			}
-		}
-		// The overlay could have included an entirely new package or an
-		// ad-hoc package. An ad-hoc package is one that we have manually
-		// constructed from inadequate `go list` results for a file= query.
-		// It will have the ID command-line-arguments.
-		if pkg == nil || pkg.ID == "command-line-arguments" {
-			// Try to find the module or gopath dir the file is contained in.
-			// Then for modules, add the module opath to the beginning.
-			pkgPath, ok, err := state.getPkgPath(dir)
-			if err != nil {
-				return nil, nil, err
-			}
-			if !ok {
-				break
-			}
-			var forTest string // only set for x tests
-			isXTest := strings.HasSuffix(pkgName, "_test")
-			if isXTest {
-				forTest = pkgPath
-				pkgPath += "_test"
-			}
-			id := pkgPath
-			if isTestFile {
-				if isXTest {
-					id = fmt.Sprintf("%s [%s.test]", pkgPath, forTest)
-				} else {
-					id = fmt.Sprintf("%s [%s.test]", pkgPath, pkgPath)
-				}
-			}
-			if pkg != nil {
-				// TODO(rstambler): We should change the package's path and ID
-				// here. The only issue is that this messes with the roots.
-			} else {
-				// Try to reclaim a package with the same ID, if it exists in the response.
-				for _, p := range response.dr.Packages {
-					if reclaimPackage(p, id, opath, contents) {
-						pkg = p
-						break
-					}
-				}
-				// Otherwise, create a new package.
-				if pkg == nil {
-					pkg = &Package{
-						PkgPath: pkgPath,
-						ID:      id,
-						Name:    pkgName,
-						Imports: make(map[string]*Package),
-					}
-					response.addPackage(pkg)
-					havePkgs[pkg.PkgPath] = id
-					// Add the production package's sources for a test variant.
-					if isTestFile && !isXTest && testVariantOf != nil {
-						pkg.GoFiles = append(pkg.GoFiles, testVariantOf.GoFiles...)
-						pkg.CompiledGoFiles = append(pkg.CompiledGoFiles, testVariantOf.CompiledGoFiles...)
-						// Add the package under test and its imports to the test variant.
-						pkg.forTest = testVariantOf.PkgPath
-						for k, v := range testVariantOf.Imports {
-							pkg.Imports[k] = &Package{ID: v.ID}
-						}
-					}
-					if isXTest {
-						pkg.forTest = forTest
-					}
-				}
-			}
-		}
-		if !fileExists {
-			pkg.GoFiles = append(pkg.GoFiles, opath)
-			// TODO(matloob): Adding the file to CompiledGoFiles can exhibit the wrong behavior
-			// if the file will be ignored due to its build tags.
-			pkg.CompiledGoFiles = append(pkg.CompiledGoFiles, opath)
-			modifiedPkgsSet[pkg.ID] = true
-		}
-		imports, err := extractImports(opath, contents)
-		if err != nil {
-			// Let the parser or type checker report errors later.
-			continue
-		}
-		for _, imp := range imports {
-			// TODO(rstambler): If the package is an x test and the import has
-			// a test variant, make sure to replace it.
-			if _, found := pkg.Imports[imp]; found {
-				continue
-			}
-			overlayAddsImports = true
-			id, ok := havePkgs[imp]
-			if !ok {
-				var err error
-				id, err = state.resolveImport(dir, imp)
-				if err != nil {
-					return nil, nil, err
-				}
-			}
-			pkg.Imports[imp] = &Package{ID: id}
-			// Add dependencies to the non-test variant version of this package as well.
-			if testVariantOf != nil {
-				testVariantOf.Imports[imp] = &Package{ID: id}
-			}
-		}
-	}
-
-	// toPkgPath guesses the package path given the id.
-	toPkgPath := func(sourceDir, id string) (string, error) {
-		if i := strings.IndexByte(id, ' '); i >= 0 {
-			return state.resolveImport(sourceDir, id[:i])
-		}
-		return state.resolveImport(sourceDir, id)
-	}
-
-	// Now that new packages have been created, do another pass to determine
-	// the new set of missing packages.
-	for _, pkg := range response.dr.Packages {
-		for _, imp := range pkg.Imports {
-			if len(pkg.GoFiles) == 0 {
-				return nil, nil, fmt.Errorf("cannot resolve imports for package %q with no Go files", pkg.PkgPath)
-			}
-			pkgPath, err := toPkgPath(filepath.Dir(pkg.GoFiles[0]), imp.ID)
-			if err != nil {
-				return nil, nil, err
-			}
-			if _, ok := havePkgs[pkgPath]; !ok {
-				needPkgsSet[pkgPath] = true
-			}
-		}
-	}
-
-	if overlayAddsImports {
-		needPkgs = make([]string, 0, len(needPkgsSet))
-		for pkg := range needPkgsSet {
-			needPkgs = append(needPkgs, pkg)
-		}
-	}
-	modifiedPkgs = make([]string, 0, len(modifiedPkgsSet))
-	for pkg := range modifiedPkgsSet {
-		modifiedPkgs = append(modifiedPkgs, pkg)
-	}
-	return modifiedPkgs, needPkgs, err
-}
-
-// resolveImport finds the ID of a package given its import path.
-// In particular, it will find the right vendored copy when in GOPATH mode.
-func (state *golistState) resolveImport(sourceDir, importPath string) (string, error) {
-	env, err := state.getEnv()
-	if err != nil {
-		return "", err
-	}
-	if env["GOMOD"] != "" {
-		return importPath, nil
-	}
-
-	searchDir := sourceDir
-	for {
-		vendorDir := filepath.Join(searchDir, "vendor")
-		exists, ok := state.vendorDirs[vendorDir]
-		if !ok {
-			info, err := os.Stat(vendorDir)
-			exists = err == nil && info.IsDir()
-			state.vendorDirs[vendorDir] = exists
-		}
-
-		if exists {
-			vendoredPath := filepath.Join(vendorDir, importPath)
-			if info, err := os.Stat(vendoredPath); err == nil && info.IsDir() {
-				// We should probably check for .go files here, but shame on anyone who fools us.
-				path, ok, err := state.getPkgPath(vendoredPath)
-				if err != nil {
-					return "", err
-				}
-				if ok {
-					return path, nil
-				}
-			}
-		}
-
-		// We know we've hit the top of the filesystem when we Dir / and get /,
-		// or C:\ and get C:\, etc.
-		next := filepath.Dir(searchDir)
-		if next == searchDir {
-			break
-		}
-		searchDir = next
-	}
-	return importPath, nil
-}
-
-func hasTestFiles(p *Package) bool {
-	for _, f := range p.GoFiles {
-		if strings.HasSuffix(f, "_test.go") {
-			return true
-		}
-	}
-	return false
-}
-
-// determineRootDirs returns a mapping from absolute directories that could
-// contain code to their corresponding import path prefixes.
-func (state *golistState) determineRootDirs() (map[string]string, error) {
-	env, err := state.getEnv()
-	if err != nil {
-		return nil, err
-	}
-	if env["GOMOD"] != "" {
-		state.rootsOnce.Do(func() {
-			state.rootDirs, state.rootDirsError = state.determineRootDirsModules()
-		})
-	} else {
-		state.rootsOnce.Do(func() {
-			state.rootDirs, state.rootDirsError = state.determineRootDirsGOPATH()
-		})
-	}
-	return state.rootDirs, state.rootDirsError
-}
-
-func (state *golistState) determineRootDirsModules() (map[string]string, error) {
-	// List all of the modules--the first will be the directory for the main
-	// module. Any replaced modules will also need to be treated as roots.
-	// Editing files in the module cache isn't a great idea, so we don't
-	// plan to ever support that.
-	out, err := state.invokeGo("list", "-m", "-json", "all")
-	if err != nil {
-		// 'go list all' will fail if we're outside of a module and
-		// GO111MODULE=on. Try falling back without 'all'.
-		var innerErr error
-		out, innerErr = state.invokeGo("list", "-m", "-json")
-		if innerErr != nil {
-			return nil, err
-		}
-	}
-	roots := map[string]string{}
-	modules := map[string]string{}
-	var i int
-	for dec := json.NewDecoder(out); dec.More(); {
-		mod := new(gocommand.ModuleJSON)
-		if err := dec.Decode(mod); err != nil {
-			return nil, err
-		}
-		if mod.Dir != "" && mod.Path != "" {
-			// This is a valid module; add it to the map.
-			absDir, err := filepath.Abs(mod.Dir)
-			if err != nil {
-				return nil, err
-			}
-			modules[absDir] = mod.Path
-			// The first result is the main module.
-			if i == 0 || mod.Replace != nil && mod.Replace.Path != "" {
-				roots[absDir] = mod.Path
-			}
-		}
-		i++
-	}
-	return roots, nil
-}
-
-func (state *golistState) determineRootDirsGOPATH() (map[string]string, error) {
-	m := map[string]string{}
-	for _, dir := range filepath.SplitList(state.mustGetEnv()["GOPATH"]) {
-		absDir, err := filepath.Abs(dir)
-		if err != nil {
-			return nil, err
-		}
-		m[filepath.Join(absDir, "src")] = ""
-	}
-	return m, nil
-}
-
-func extractImports(filename string, contents []byte) ([]string, error) {
-	f, err := parser.ParseFile(token.NewFileSet(), filename, contents, parser.ImportsOnly) // TODO(matloob): reuse fileset?
-	if err != nil {
-		return nil, err
-	}
-	var res []string
-	for _, imp := range f.Imports {
-		quotedPath := imp.Path.Value
-		path, err := strconv.Unquote(quotedPath)
-		if err != nil {
-			return nil, err
-		}
-		res = append(res, path)
-	}
-	return res, nil
-}
-
-// reclaimPackage attempts to reuse a package that failed to load in an overlay.
-//
-// If the package has errors and has no Name, GoFiles, or Imports,
-// then it's possible that it doesn't yet exist on disk.
-func reclaimPackage(pkg *Package, id string, filename string, contents []byte) bool {
-	// TODO(rstambler): Check the message of the actual error?
-	// It differs between $GOPATH and module mode.
-	if pkg.ID != id {
-		return false
-	}
-	if len(pkg.Errors) != 1 {
-		return false
-	}
-	if pkg.Name != "" || pkg.ExportFile != "" {
-		return false
-	}
-	if len(pkg.GoFiles) > 0 || len(pkg.CompiledGoFiles) > 0 || len(pkg.OtherFiles) > 0 {
-		return false
-	}
-	if len(pkg.Imports) > 0 {
-		return false
-	}
-	pkgName, ok := extractPackageName(filename, contents)
-	if !ok {
-		return false
-	}
-	pkg.Name = pkgName
-	pkg.Errors = nil
-	return true
-}
-
-func extractPackageName(filename string, contents []byte) (string, bool) {
-	// TODO(rstambler): Check the message of the actual error?
-	// It differs between $GOPATH and module mode.
-	f, err := parser.ParseFile(token.NewFileSet(), filename, contents, parser.PackageClauseOnly) // TODO(matloob): reuse fileset?
-	if err != nil {
-		return "", false
-	}
-	return f.Name.Name, true
-}
-
-// commonDir returns the directory that all files are in, "" if files is empty,
-// or an error if they aren't in the same directory.
-func commonDir(files []string) (string, error) {
-	seen := make(map[string]bool)
-	for _, f := range files {
-		seen[filepath.Dir(f)] = true
-	}
-	if len(seen) > 1 {
-		return "", fmt.Errorf("files (%v) are in more than one directory: %v", files, seen)
-	}
-	for k := range seen {
-		// seen has only one element; return it.
-		return k, nil
-	}
-	return "", nil // no files
-}
-
-// It is possible that the files in the disk directory dir have a different package
-// name from newName, which is deduced from the overlays. If they all have a different
-// package name, and they all have the same package name, then that name becomes
-// the package name.
-// It returns true if it changes the package name, false otherwise.
-func maybeFixPackageName(newName string, isTestFile bool, pkgsOfDir []*Package) {
-	names := make(map[string]int)
-	for _, p := range pkgsOfDir {
-		names[p.Name]++
-	}
-	if len(names) != 1 {
-		// some files are in different packages
-		return
-	}
-	var oldName string
-	for k := range names {
-		oldName = k
-	}
-	if newName == oldName {
-		return
-	}
-	// We might have a case where all of the package names in the directory are
-	// the same, but the overlay file is for an x test, which belongs to its
-	// own package. If the x test does not yet exist on disk, we may not yet
-	// have its package name on disk, but we should not rename the packages.
-	//
-	// We use a heuristic to determine if this file belongs to an x test:
-	// The test file should have a package name whose package name has a _test
-	// suffix or looks like "newName_test".
-	maybeXTest := strings.HasPrefix(oldName+"_test", newName) || strings.HasSuffix(newName, "_test")
-	if isTestFile && maybeXTest {
-		return
-	}
-	for _, p := range pkgsOfDir {
-		p.Name = newName
-	}
-}
-
-// This function is copy-pasted from
-// https://github.com/golang/go/blob/9706f510a5e2754595d716bd64be8375997311fb/src/cmd/go/internal/search/search.go#L360.
-// It should be deleted when we remove support for overlays from go/packages.
-//
-// NOTE: This does not handle any ./... or ./ style queries, as this function
-// doesn't know the working directory.
-//
-// matchPattern(pattern)(name) reports whether
-// name matches pattern. Pattern is a limited glob
-// pattern in which '...' means 'any string' and there
-// is no other special syntax.
-// Unfortunately, there are two special cases. Quoting "go help packages":
-//
-// First, /... at the end of the pattern can match an empty string,
-// so that net/... matches both net and packages in its subdirectories, like net/http.
-// Second, any slash-separated pattern element containing a wildcard never
-// participates in a match of the "vendor" element in the path of a vendored
-// package, so that ./... does not match packages in subdirectories of
-// ./vendor or ./mycode/vendor, but ./vendor/... and ./mycode/vendor/... do.
-// Note, however, that a directory named vendor that itself contains code
-// is not a vendored package: cmd/vendor would be a command named vendor,
-// and the pattern cmd/... matches it.
-func matchPattern(pattern string) func(name string) bool {
-	// Convert pattern to regular expression.
-	// The strategy for the trailing /... is to nest it in an explicit ? expression.
-	// The strategy for the vendor exclusion is to change the unmatchable
-	// vendor strings to a disallowed code point (vendorChar) and to use
-	// "(anything but that codepoint)*" as the implementation of the ... wildcard.
-	// This is a bit complicated but the obvious alternative,
-	// namely a hand-written search like in most shell glob matchers,
-	// is too easy to make accidentally exponential.
-	// Using package regexp guarantees linear-time matching.
-
-	const vendorChar = "\x00"
-
-	if strings.Contains(pattern, vendorChar) {
-		return func(name string) bool { return false }
-	}
-
-	re := regexp.QuoteMeta(pattern)
-	re = replaceVendor(re, vendorChar)
-	switch {
-	case strings.HasSuffix(re, `/`+vendorChar+`/\.\.\.`):
-		re = strings.TrimSuffix(re, `/`+vendorChar+`/\.\.\.`) + `(/vendor|/` + vendorChar + `/\.\.\.)`
-	case re == vendorChar+`/\.\.\.`:
-		re = `(/vendor|/` + vendorChar + `/\.\.\.)`
-	case strings.HasSuffix(re, `/\.\.\.`):
-		re = strings.TrimSuffix(re, `/\.\.\.`) + `(/\.\.\.)?`
-	}
-	re = strings.ReplaceAll(re, `\.\.\.`, `[^`+vendorChar+`]*`)
-
-	reg := regexp.MustCompile(`^` + re + `$`)
-
-	return func(name string) bool {
-		if strings.Contains(name, vendorChar) {
-			return false
-		}
-		return reg.MatchString(replaceVendor(name, vendorChar))
-	}
-}
-
-// replaceVendor returns the result of replacing
-// non-trailing vendor path elements in x with repl.
-func replaceVendor(x, repl string) string {
-	if !strings.Contains(x, "vendor") {
-		return x
-	}
-	elem := strings.Split(x, "/")
-	for i := 0; i < len(elem)-1; i++ {
-		if elem[i] == "vendor" {
-			elem[i] = repl
-		}
-	}
-	return strings.Join(elem, "/")
-}
diff --git a/vendor/golang.org/x/tools/go/packages/loadmode_string.go b/vendor/golang.org/x/tools/go/packages/loadmode_string.go
deleted file mode 100644
index 7ea37e7eea..0000000000
--- a/vendor/golang.org/x/tools/go/packages/loadmode_string.go
+++ /dev/null
@@ -1,57 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package packages
-
-import (
-	"fmt"
-	"strings"
-)
-
-var allModes = []LoadMode{
-	NeedName,
-	NeedFiles,
-	NeedCompiledGoFiles,
-	NeedImports,
-	NeedDeps,
-	NeedExportsFile,
-	NeedTypes,
-	NeedSyntax,
-	NeedTypesInfo,
-	NeedTypesSizes,
-}
-
-var modeStrings = []string{
-	"NeedName",
-	"NeedFiles",
-	"NeedCompiledGoFiles",
-	"NeedImports",
-	"NeedDeps",
-	"NeedExportsFile",
-	"NeedTypes",
-	"NeedSyntax",
-	"NeedTypesInfo",
-	"NeedTypesSizes",
-}
-
-func (mod LoadMode) String() string {
-	m := mod
-	if m == 0 {
-		return "LoadMode(0)"
-	}
-	var out []string
-	for i, x := range allModes {
-		if x > m {
-			break
-		}
-		if (m & x) != 0 {
-			out = append(out, modeStrings[i])
-			m = m ^ x
-		}
-	}
-	if m != 0 {
-		out = append(out, "Unknown")
-	}
-	return fmt.Sprintf("LoadMode(%s)", strings.Join(out, "|"))
-}
diff --git a/vendor/golang.org/x/tools/go/packages/packages.go b/vendor/golang.org/x/tools/go/packages/packages.go
deleted file mode 100644
index 38475e8712..0000000000
--- a/vendor/golang.org/x/tools/go/packages/packages.go
+++ /dev/null
@@ -1,1233 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package packages
-
-// See doc.go for package documentation and implementation notes.
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"go/ast"
-	"go/parser"
-	"go/scanner"
-	"go/token"
-	"go/types"
-	"io/ioutil"
-	"log"
-	"os"
-	"path/filepath"
-	"strings"
-	"sync"
-	"time"
-
-	"golang.org/x/tools/go/gcexportdata"
-	"golang.org/x/tools/internal/gocommand"
-	"golang.org/x/tools/internal/packagesinternal"
-	"golang.org/x/tools/internal/typesinternal"
-)
-
-// A LoadMode controls the amount of detail to return when loading.
-// The bits below can be combined to specify which fields should be
-// filled in the result packages.
-// The zero value is a special case, equivalent to combining
-// the NeedName, NeedFiles, and NeedCompiledGoFiles bits.
-// ID and Errors (if present) will always be filled.
-// Load may return more information than requested.
-type LoadMode int
-
-// TODO(matloob): When a V2 of go/packages is released, rename NeedExportsFile to
-// NeedExportFile to make it consistent with the Package field it's adding.
-
-const (
-	// NeedName adds Name and PkgPath.
-	NeedName LoadMode = 1 << iota
-
-	// NeedFiles adds GoFiles and OtherFiles.
-	NeedFiles
-
-	// NeedCompiledGoFiles adds CompiledGoFiles.
-	NeedCompiledGoFiles
-
-	// NeedImports adds Imports. If NeedDeps is not set, the Imports field will contain
-	// "placeholder" Packages with only the ID set.
-	NeedImports
-
-	// NeedDeps adds the fields requested by the LoadMode in the packages in Imports.
-	NeedDeps
-
-	// NeedExportsFile adds ExportFile.
-	NeedExportsFile
-
-	// NeedTypes adds Types, Fset, and IllTyped.
-	NeedTypes
-
-	// NeedSyntax adds Syntax.
-	NeedSyntax
-
-	// NeedTypesInfo adds TypesInfo.
-	NeedTypesInfo
-
-	// NeedTypesSizes adds TypesSizes.
-	NeedTypesSizes
-
-	// typecheckCgo enables full support for type checking cgo. Requires Go 1.15+.
-	// Modifies CompiledGoFiles and Types, and has no effect on its own.
-	typecheckCgo
-
-	// NeedModule adds Module.
-	NeedModule
-)
-
-const (
-	// Deprecated: LoadFiles exists for historical compatibility
-	// and should not be used. Please directly specify the needed fields using the Need values.
-	LoadFiles = NeedName | NeedFiles | NeedCompiledGoFiles
-
-	// Deprecated: LoadImports exists for historical compatibility
-	// and should not be used. Please directly specify the needed fields using the Need values.
-	LoadImports = LoadFiles | NeedImports
-
-	// Deprecated: LoadTypes exists for historical compatibility
-	// and should not be used. Please directly specify the needed fields using the Need values.
-	LoadTypes = LoadImports | NeedTypes | NeedTypesSizes
-
-	// Deprecated: LoadSyntax exists for historical compatibility
-	// and should not be used. Please directly specify the needed fields using the Need values.
-	LoadSyntax = LoadTypes | NeedSyntax | NeedTypesInfo
-
-	// Deprecated: LoadAllSyntax exists for historical compatibility
-	// and should not be used. Please directly specify the needed fields using the Need values.
-	LoadAllSyntax = LoadSyntax | NeedDeps
-)
-
-// A Config specifies details about how packages should be loaded.
-// The zero value is a valid configuration.
-// Calls to Load do not modify this struct.
-type Config struct {
-	// Mode controls the level of information returned for each package.
-	Mode LoadMode
-
-	// Context specifies the context for the load operation.
-	// If the context is cancelled, the loader may stop early
-	// and return an ErrCancelled error.
-	// If Context is nil, the load cannot be cancelled.
-	Context context.Context
-
-	// Logf is the logger for the config.
-	// If the user provides a logger, debug logging is enabled.
-	// If the GOPACKAGESDEBUG environment variable is set to true,
-	// but the logger is nil, default to log.Printf.
-	Logf func(format string, args ...interface{})
-
-	// Dir is the directory in which to run the build system's query tool
-	// that provides information about the packages.
-	// If Dir is empty, the tool is run in the current directory.
-	Dir string
-
-	// Env is the environment to use when invoking the build system's query tool.
-	// If Env is nil, the current environment is used.
-	// As in os/exec's Cmd, only the last value in the slice for
-	// each environment key is used. To specify the setting of only
-	// a few variables, append to the current environment, as in:
-	//
-	//	opt.Env = append(os.Environ(), "GOOS=plan9", "GOARCH=386")
-	//
-	Env []string
-
-	// gocmdRunner guards go command calls from concurrency errors.
-	gocmdRunner *gocommand.Runner
-
-	// BuildFlags is a list of command-line flags to be passed through to
-	// the build system's query tool.
-	BuildFlags []string
-
-	// modFile will be used for -modfile in go command invocations.
-	modFile string
-
-	// modFlag will be used for -modfile in go command invocations.
-	modFlag string
-
-	// Fset provides source position information for syntax trees and types.
-	// If Fset is nil, Load will use a new fileset, but preserve Fset's value.
-	Fset *token.FileSet
-
-	// ParseFile is called to read and parse each file
-	// when preparing a package's type-checked syntax tree.
-	// It must be safe to call ParseFile simultaneously from multiple goroutines.
-	// If ParseFile is nil, the loader will uses parser.ParseFile.
-	//
-	// ParseFile should parse the source from src and use filename only for
-	// recording position information.
-	//
-	// An application may supply a custom implementation of ParseFile
-	// to change the effective file contents or the behavior of the parser,
-	// or to modify the syntax tree. For example, selectively eliminating
-	// unwanted function bodies can significantly accelerate type checking.
-	ParseFile func(fset *token.FileSet, filename string, src []byte) (*ast.File, error)
-
-	// If Tests is set, the loader includes not just the packages
-	// matching a particular pattern but also any related test packages,
-	// including test-only variants of the package and the test executable.
-	//
-	// For example, when using the go command, loading "fmt" with Tests=true
-	// returns four packages, with IDs "fmt" (the standard package),
-	// "fmt [fmt.test]" (the package as compiled for the test),
-	// "fmt_test" (the test functions from source files in package fmt_test),
-	// and "fmt.test" (the test binary).
-	//
-	// In build systems with explicit names for tests,
-	// setting Tests may have no effect.
-	Tests bool
-
-	// Overlay provides a mapping of absolute file paths to file contents.
-	// If the file with the given path already exists, the parser will use the
-	// alternative file contents provided by the map.
-	//
-	// Overlays provide incomplete support for when a given file doesn't
-	// already exist on disk. See the package doc above for more details.
-	Overlay map[string][]byte
-}
-
-// driver is the type for functions that query the build system for the
-// packages named by the patterns.
-type driver func(cfg *Config, patterns ...string) (*driverResponse, error)
-
-// driverResponse contains the results for a driver query.
-type driverResponse struct {
-	// NotHandled is returned if the request can't be handled by the current
-	// driver. If an external driver returns a response with NotHandled, the
-	// rest of the driverResponse is ignored, and go/packages will fallback
-	// to the next driver. If go/packages is extended in the future to support
-	// lists of multiple drivers, go/packages will fall back to the next driver.
-	NotHandled bool
-
-	// Sizes, if not nil, is the types.Sizes to use when type checking.
-	Sizes *types.StdSizes
-
-	// Roots is the set of package IDs that make up the root packages.
-	// We have to encode this separately because when we encode a single package
-	// we cannot know if it is one of the roots as that requires knowledge of the
-	// graph it is part of.
-	Roots []string `json:",omitempty"`
-
-	// Packages is the full set of packages in the graph.
-	// The packages are not connected into a graph.
-	// The Imports if populated will be stubs that only have their ID set.
-	// Imports will be connected and then type and syntax information added in a
-	// later pass (see refine).
-	Packages []*Package
-}
-
-// Load loads and returns the Go packages named by the given patterns.
-//
-// Config specifies loading options;
-// nil behaves the same as an empty Config.
-//
-// Load returns an error if any of the patterns was invalid
-// as defined by the underlying build system.
-// It may return an empty list of packages without an error,
-// for instance for an empty expansion of a valid wildcard.
-// Errors associated with a particular package are recorded in the
-// corresponding Package's Errors list, and do not cause Load to
-// return an error. Clients may need to handle such errors before
-// proceeding with further analysis. The PrintErrors function is
-// provided for convenient display of all errors.
-func Load(cfg *Config, patterns ...string) ([]*Package, error) {
-	l := newLoader(cfg)
-	response, err := defaultDriver(&l.Config, patterns...)
-	if err != nil {
-		return nil, err
-	}
-	l.sizes = response.Sizes
-	return l.refine(response.Roots, response.Packages...)
-}
-
-// defaultDriver is a driver that implements go/packages' fallback behavior.
-// It will try to request to an external driver, if one exists. If there's
-// no external driver, or the driver returns a response with NotHandled set,
-// defaultDriver will fall back to the go list driver.
-func defaultDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
-	driver := findExternalDriver(cfg)
-	if driver == nil {
-		driver = goListDriver
-	}
-	response, err := driver(cfg, patterns...)
-	if err != nil {
-		return response, err
-	} else if response.NotHandled {
-		return goListDriver(cfg, patterns...)
-	}
-	return response, nil
-}
-
-// A Package describes a loaded Go package.
-type Package struct {
-	// ID is a unique identifier for a package,
-	// in a syntax provided by the underlying build system.
-	//
-	// Because the syntax varies based on the build system,
-	// clients should treat IDs as opaque and not attempt to
-	// interpret them.
-	ID string
-
-	// Name is the package name as it appears in the package source code.
-	Name string
-
-	// PkgPath is the package path as used by the go/types package.
-	PkgPath string
-
-	// Errors contains any errors encountered querying the metadata
-	// of the package, or while parsing or type-checking its files.
-	Errors []Error
-
-	// GoFiles lists the absolute file paths of the package's Go source files.
-	GoFiles []string
-
-	// CompiledGoFiles lists the absolute file paths of the package's source
-	// files that are suitable for type checking.
-	// This may differ from GoFiles if files are processed before compilation.
-	CompiledGoFiles []string
-
-	// OtherFiles lists the absolute file paths of the package's non-Go source files,
-	// including assembly, C, C++, Fortran, Objective-C, SWIG, and so on.
-	OtherFiles []string
-
-	// IgnoredFiles lists source files that are not part of the package
-	// using the current build configuration but that might be part of
-	// the package using other build configurations.
-	IgnoredFiles []string
-
-	// ExportFile is the absolute path to a file containing type
-	// information for the package as provided by the build system.
-	ExportFile string
-
-	// Imports maps import paths appearing in the package's Go source files
-	// to corresponding loaded Packages.
-	Imports map[string]*Package
-
-	// Types provides type information for the package.
-	// The NeedTypes LoadMode bit sets this field for packages matching the
-	// patterns; type information for dependencies may be missing or incomplete,
-	// unless NeedDeps and NeedImports are also set.
-	Types *types.Package
-
-	// Fset provides position information for Types, TypesInfo, and Syntax.
-	// It is set only when Types is set.
-	Fset *token.FileSet
-
-	// IllTyped indicates whether the package or any dependency contains errors.
-	// It is set only when Types is set.
-	IllTyped bool
-
-	// Syntax is the package's syntax trees, for the files listed in CompiledGoFiles.
-	//
-	// The NeedSyntax LoadMode bit populates this field for packages matching the patterns.
-	// If NeedDeps and NeedImports are also set, this field will also be populated
-	// for dependencies.
-	Syntax []*ast.File
-
-	// TypesInfo provides type information about the package's syntax trees.
-	// It is set only when Syntax is set.
-	TypesInfo *types.Info
-
-	// TypesSizes provides the effective size function for types in TypesInfo.
-	TypesSizes types.Sizes
-
-	// forTest is the package under test, if any.
-	forTest string
-
-	// module is the module information for the package if it exists.
-	Module *Module
-}
-
-// Module provides module information for a package.
-type Module struct {
-	Path      string       // module path
-	Version   string       // module version
-	Replace   *Module      // replaced by this module
-	Time      *time.Time   // time version was created
-	Main      bool         // is this the main module?
-	Indirect  bool         // is this module only an indirect dependency of main module?
-	Dir       string       // directory holding files for this module, if any
-	GoMod     string       // path to go.mod file used when loading this module, if any
-	GoVersion string       // go version used in module
-	Error     *ModuleError // error loading module
-}
-
-// ModuleError holds errors loading a module.
-type ModuleError struct {
-	Err string // the error itself
-}
-
-func init() {
-	packagesinternal.GetForTest = func(p interface{}) string {
-		return p.(*Package).forTest
-	}
-	packagesinternal.GetGoCmdRunner = func(config interface{}) *gocommand.Runner {
-		return config.(*Config).gocmdRunner
-	}
-	packagesinternal.SetGoCmdRunner = func(config interface{}, runner *gocommand.Runner) {
-		config.(*Config).gocmdRunner = runner
-	}
-	packagesinternal.SetModFile = func(config interface{}, value string) {
-		config.(*Config).modFile = value
-	}
-	packagesinternal.SetModFlag = func(config interface{}, value string) {
-		config.(*Config).modFlag = value
-	}
-	packagesinternal.TypecheckCgo = int(typecheckCgo)
-}
-
-// An Error describes a problem with a package's metadata, syntax, or types.
-type Error struct {
-	Pos  string // "file:line:col" or "file:line" or "" or "-"
-	Msg  string
-	Kind ErrorKind
-}
-
-// ErrorKind describes the source of the error, allowing the user to
-// differentiate between errors generated by the driver, the parser, or the
-// type-checker.
-type ErrorKind int
-
-const (
-	UnknownError ErrorKind = iota
-	ListError
-	ParseError
-	TypeError
-)
-
-func (err Error) Error() string {
-	pos := err.Pos
-	if pos == "" {
-		pos = "-" // like token.Position{}.String()
-	}
-	return pos + ": " + err.Msg
-}
-
-// flatPackage is the JSON form of Package
-// It drops all the type and syntax fields, and transforms the Imports
-//
-// TODO(adonovan): identify this struct with Package, effectively
-// publishing the JSON protocol.
-type flatPackage struct {
-	ID              string
-	Name            string            `json:",omitempty"`
-	PkgPath         string            `json:",omitempty"`
-	Errors          []Error           `json:",omitempty"`
-	GoFiles         []string          `json:",omitempty"`
-	CompiledGoFiles []string          `json:",omitempty"`
-	OtherFiles      []string          `json:",omitempty"`
-	IgnoredFiles    []string          `json:",omitempty"`
-	ExportFile      string            `json:",omitempty"`
-	Imports         map[string]string `json:",omitempty"`
-}
-
-// MarshalJSON returns the Package in its JSON form.
-// For the most part, the structure fields are written out unmodified, and
-// the type and syntax fields are skipped.
-// The imports are written out as just a map of path to package id.
-// The errors are written using a custom type that tries to preserve the
-// structure of error types we know about.
-//
-// This method exists to enable support for additional build systems.  It is
-// not intended for use by clients of the API and we may change the format.
-func (p *Package) MarshalJSON() ([]byte, error) {
-	flat := &flatPackage{
-		ID:              p.ID,
-		Name:            p.Name,
-		PkgPath:         p.PkgPath,
-		Errors:          p.Errors,
-		GoFiles:         p.GoFiles,
-		CompiledGoFiles: p.CompiledGoFiles,
-		OtherFiles:      p.OtherFiles,
-		IgnoredFiles:    p.IgnoredFiles,
-		ExportFile:      p.ExportFile,
-	}
-	if len(p.Imports) > 0 {
-		flat.Imports = make(map[string]string, len(p.Imports))
-		for path, ipkg := range p.Imports {
-			flat.Imports[path] = ipkg.ID
-		}
-	}
-	return json.Marshal(flat)
-}
-
-// UnmarshalJSON reads in a Package from its JSON format.
-// See MarshalJSON for details about the format accepted.
-func (p *Package) UnmarshalJSON(b []byte) error {
-	flat := &flatPackage{}
-	if err := json.Unmarshal(b, &flat); err != nil {
-		return err
-	}
-	*p = Package{
-		ID:              flat.ID,
-		Name:            flat.Name,
-		PkgPath:         flat.PkgPath,
-		Errors:          flat.Errors,
-		GoFiles:         flat.GoFiles,
-		CompiledGoFiles: flat.CompiledGoFiles,
-		OtherFiles:      flat.OtherFiles,
-		ExportFile:      flat.ExportFile,
-	}
-	if len(flat.Imports) > 0 {
-		p.Imports = make(map[string]*Package, len(flat.Imports))
-		for path, id := range flat.Imports {
-			p.Imports[path] = &Package{ID: id}
-		}
-	}
-	return nil
-}
-
-func (p *Package) String() string { return p.ID }
-
-// loaderPackage augments Package with state used during the loading phase
-type loaderPackage struct {
-	*Package
-	importErrors map[string]error // maps each bad import to its error
-	loadOnce     sync.Once
-	color        uint8 // for cycle detection
-	needsrc      bool  // load from source (Mode >= LoadTypes)
-	needtypes    bool  // type information is either requested or depended on
-	initial      bool  // package was matched by a pattern
-}
-
-// loader holds the working state of a single call to load.
-type loader struct {
-	pkgs map[string]*loaderPackage
-	Config
-	sizes        types.Sizes
-	parseCache   map[string]*parseValue
-	parseCacheMu sync.Mutex
-	exportMu     sync.Mutex // enforces mutual exclusion of exportdata operations
-
-	// Config.Mode contains the implied mode (see impliedLoadMode).
-	// Implied mode contains all the fields we need the data for.
-	// In requestedMode there are the actually requested fields.
-	// We'll zero them out before returning packages to the user.
-	// This makes it easier for us to get the conditions where
-	// we need certain modes right.
-	requestedMode LoadMode
-}
-
-type parseValue struct {
-	f     *ast.File
-	err   error
-	ready chan struct{}
-}
-
-func newLoader(cfg *Config) *loader {
-	ld := &loader{
-		parseCache: map[string]*parseValue{},
-	}
-	if cfg != nil {
-		ld.Config = *cfg
-		// If the user has provided a logger, use it.
-		ld.Config.Logf = cfg.Logf
-	}
-	if ld.Config.Logf == nil {
-		// If the GOPACKAGESDEBUG environment variable is set to true,
-		// but the user has not provided a logger, default to log.Printf.
-		if debug {
-			ld.Config.Logf = log.Printf
-		} else {
-			ld.Config.Logf = func(format string, args ...interface{}) {}
-		}
-	}
-	if ld.Config.Mode == 0 {
-		ld.Config.Mode = NeedName | NeedFiles | NeedCompiledGoFiles // Preserve zero behavior of Mode for backwards compatibility.
-	}
-	if ld.Config.Env == nil {
-		ld.Config.Env = os.Environ()
-	}
-	if ld.Config.gocmdRunner == nil {
-		ld.Config.gocmdRunner = &gocommand.Runner{}
-	}
-	if ld.Context == nil {
-		ld.Context = context.Background()
-	}
-	if ld.Dir == "" {
-		if dir, err := os.Getwd(); err == nil {
-			ld.Dir = dir
-		}
-	}
-
-	// Save the actually requested fields. We'll zero them out before returning packages to the user.
-	ld.requestedMode = ld.Mode
-	ld.Mode = impliedLoadMode(ld.Mode)
-
-	if ld.Mode&NeedTypes != 0 || ld.Mode&NeedSyntax != 0 {
-		if ld.Fset == nil {
-			ld.Fset = token.NewFileSet()
-		}
-
-		// ParseFile is required even in LoadTypes mode
-		// because we load source if export data is missing.
-		if ld.ParseFile == nil {
-			ld.ParseFile = func(fset *token.FileSet, filename string, src []byte) (*ast.File, error) {
-				const mode = parser.AllErrors | parser.ParseComments
-				return parser.ParseFile(fset, filename, src, mode)
-			}
-		}
-	}
-
-	return ld
-}
-
-// refine connects the supplied packages into a graph and then adds type and
-// and syntax information as requested by the LoadMode.
-func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
-	rootMap := make(map[string]int, len(roots))
-	for i, root := range roots {
-		rootMap[root] = i
-	}
-	ld.pkgs = make(map[string]*loaderPackage)
-	// first pass, fixup and build the map and roots
-	var initial = make([]*loaderPackage, len(roots))
-	for _, pkg := range list {
-		rootIndex := -1
-		if i, found := rootMap[pkg.ID]; found {
-			rootIndex = i
-		}
-
-		// Overlays can invalidate export data.
-		// TODO(matloob): make this check fine-grained based on dependencies on overlaid files
-		exportDataInvalid := len(ld.Overlay) > 0 || pkg.ExportFile == "" && pkg.PkgPath != "unsafe"
-		// This package needs type information if the caller requested types and the package is
-		// either a root, or it's a non-root and the user requested dependencies ...
-		needtypes := (ld.Mode&NeedTypes|NeedTypesInfo != 0 && (rootIndex >= 0 || ld.Mode&NeedDeps != 0))
-		// This package needs source if the call requested source (or types info, which implies source)
-		// and the package is either a root, or itas a non- root and the user requested dependencies...
-		needsrc := ((ld.Mode&(NeedSyntax|NeedTypesInfo) != 0 && (rootIndex >= 0 || ld.Mode&NeedDeps != 0)) ||
-			// ... or if we need types and the exportData is invalid. We fall back to (incompletely)
-			// typechecking packages from source if they fail to compile.
-			(ld.Mode&NeedTypes|NeedTypesInfo != 0 && exportDataInvalid)) && pkg.PkgPath != "unsafe"
-		lpkg := &loaderPackage{
-			Package:   pkg,
-			needtypes: needtypes,
-			needsrc:   needsrc,
-		}
-		ld.pkgs[lpkg.ID] = lpkg
-		if rootIndex >= 0 {
-			initial[rootIndex] = lpkg
-			lpkg.initial = true
-		}
-	}
-	for i, root := range roots {
-		if initial[i] == nil {
-			return nil, fmt.Errorf("root package %v is missing", root)
-		}
-	}
-
-	// Materialize the import graph.
-
-	const (
-		white = 0 // new
-		grey  = 1 // in progress
-		black = 2 // complete
-	)
-
-	// visit traverses the import graph, depth-first,
-	// and materializes the graph as Packages.Imports.
-	//
-	// Valid imports are saved in the Packages.Import map.
-	// Invalid imports (cycles and missing nodes) are saved in the importErrors map.
-	// Thus, even in the presence of both kinds of errors, the Import graph remains a DAG.
-	//
-	// visit returns whether the package needs src or has a transitive
-	// dependency on a package that does. These are the only packages
-	// for which we load source code.
-	var stack []*loaderPackage
-	var visit func(lpkg *loaderPackage) bool
-	var srcPkgs []*loaderPackage
-	visit = func(lpkg *loaderPackage) bool {
-		switch lpkg.color {
-		case black:
-			return lpkg.needsrc
-		case grey:
-			panic("internal error: grey node")
-		}
-		lpkg.color = grey
-		stack = append(stack, lpkg) // push
-		stubs := lpkg.Imports       // the structure form has only stubs with the ID in the Imports
-		// If NeedImports isn't set, the imports fields will all be zeroed out.
-		if ld.Mode&NeedImports != 0 {
-			lpkg.Imports = make(map[string]*Package, len(stubs))
-			for importPath, ipkg := range stubs {
-				var importErr error
-				imp := ld.pkgs[ipkg.ID]
-				if imp == nil {
-					// (includes package "C" when DisableCgo)
-					importErr = fmt.Errorf("missing package: %q", ipkg.ID)
-				} else if imp.color == grey {
-					importErr = fmt.Errorf("import cycle: %s", stack)
-				}
-				if importErr != nil {
-					if lpkg.importErrors == nil {
-						lpkg.importErrors = make(map[string]error)
-					}
-					lpkg.importErrors[importPath] = importErr
-					continue
-				}
-
-				if visit(imp) {
-					lpkg.needsrc = true
-				}
-				lpkg.Imports[importPath] = imp.Package
-			}
-		}
-		if lpkg.needsrc {
-			srcPkgs = append(srcPkgs, lpkg)
-		}
-		if ld.Mode&NeedTypesSizes != 0 {
-			lpkg.TypesSizes = ld.sizes
-		}
-		stack = stack[:len(stack)-1] // pop
-		lpkg.color = black
-
-		return lpkg.needsrc
-	}
-
-	if ld.Mode&NeedImports == 0 {
-		// We do this to drop the stub import packages that we are not even going to try to resolve.
-		for _, lpkg := range initial {
-			lpkg.Imports = nil
-		}
-	} else {
-		// For each initial package, create its import DAG.
-		for _, lpkg := range initial {
-			visit(lpkg)
-		}
-	}
-	if ld.Mode&NeedImports != 0 && ld.Mode&NeedTypes != 0 {
-		for _, lpkg := range srcPkgs {
-			// Complete type information is required for the
-			// immediate dependencies of each source package.
-			for _, ipkg := range lpkg.Imports {
-				imp := ld.pkgs[ipkg.ID]
-				imp.needtypes = true
-			}
-		}
-	}
-	// Load type data and syntax if needed, starting at
-	// the initial packages (roots of the import DAG).
-	if ld.Mode&NeedTypes != 0 || ld.Mode&NeedSyntax != 0 {
-		var wg sync.WaitGroup
-		for _, lpkg := range initial {
-			wg.Add(1)
-			go func(lpkg *loaderPackage) {
-				ld.loadRecursive(lpkg)
-				wg.Done()
-			}(lpkg)
-		}
-		wg.Wait()
-	}
-
-	result := make([]*Package, len(initial))
-	for i, lpkg := range initial {
-		result[i] = lpkg.Package
-	}
-	for i := range ld.pkgs {
-		// Clear all unrequested fields,
-		// to catch programs that use more than they request.
-		if ld.requestedMode&NeedName == 0 {
-			ld.pkgs[i].Name = ""
-			ld.pkgs[i].PkgPath = ""
-		}
-		if ld.requestedMode&NeedFiles == 0 {
-			ld.pkgs[i].GoFiles = nil
-			ld.pkgs[i].OtherFiles = nil
-			ld.pkgs[i].IgnoredFiles = nil
-		}
-		if ld.requestedMode&NeedCompiledGoFiles == 0 {
-			ld.pkgs[i].CompiledGoFiles = nil
-		}
-		if ld.requestedMode&NeedImports == 0 {
-			ld.pkgs[i].Imports = nil
-		}
-		if ld.requestedMode&NeedExportsFile == 0 {
-			ld.pkgs[i].ExportFile = ""
-		}
-		if ld.requestedMode&NeedTypes == 0 {
-			ld.pkgs[i].Types = nil
-			ld.pkgs[i].Fset = nil
-			ld.pkgs[i].IllTyped = false
-		}
-		if ld.requestedMode&NeedSyntax == 0 {
-			ld.pkgs[i].Syntax = nil
-		}
-		if ld.requestedMode&NeedTypesInfo == 0 {
-			ld.pkgs[i].TypesInfo = nil
-		}
-		if ld.requestedMode&NeedTypesSizes == 0 {
-			ld.pkgs[i].TypesSizes = nil
-		}
-		if ld.requestedMode&NeedModule == 0 {
-			ld.pkgs[i].Module = nil
-		}
-	}
-
-	return result, nil
-}
-
-// loadRecursive loads the specified package and its dependencies,
-// recursively, in parallel, in topological order.
-// It is atomic and idempotent.
-// Precondition: ld.Mode&NeedTypes.
-func (ld *loader) loadRecursive(lpkg *loaderPackage) {
-	lpkg.loadOnce.Do(func() {
-		// Load the direct dependencies, in parallel.
-		var wg sync.WaitGroup
-		for _, ipkg := range lpkg.Imports {
-			imp := ld.pkgs[ipkg.ID]
-			wg.Add(1)
-			go func(imp *loaderPackage) {
-				ld.loadRecursive(imp)
-				wg.Done()
-			}(imp)
-		}
-		wg.Wait()
-		ld.loadPackage(lpkg)
-	})
-}
-
-// loadPackage loads the specified package.
-// It must be called only once per Package,
-// after immediate dependencies are loaded.
-// Precondition: ld.Mode & NeedTypes.
-func (ld *loader) loadPackage(lpkg *loaderPackage) {
-	if lpkg.PkgPath == "unsafe" {
-		// Fill in the blanks to avoid surprises.
-		lpkg.Types = types.Unsafe
-		lpkg.Fset = ld.Fset
-		lpkg.Syntax = []*ast.File{}
-		lpkg.TypesInfo = new(types.Info)
-		lpkg.TypesSizes = ld.sizes
-		return
-	}
-
-	// Call NewPackage directly with explicit name.
-	// This avoids skew between golist and go/types when the files'
-	// package declarations are inconsistent.
-	lpkg.Types = types.NewPackage(lpkg.PkgPath, lpkg.Name)
-	lpkg.Fset = ld.Fset
-
-	// Subtle: we populate all Types fields with an empty Package
-	// before loading export data so that export data processing
-	// never has to create a types.Package for an indirect dependency,
-	// which would then require that such created packages be explicitly
-	// inserted back into the Import graph as a final step after export data loading.
-	// The Diamond test exercises this case.
-	if !lpkg.needtypes && !lpkg.needsrc {
-		return
-	}
-	if !lpkg.needsrc {
-		ld.loadFromExportData(lpkg)
-		return // not a source package, don't get syntax trees
-	}
-
-	appendError := func(err error) {
-		// Convert various error types into the one true Error.
-		var errs []Error
-		switch err := err.(type) {
-		case Error:
-			// from driver
-			errs = append(errs, err)
-
-		case *os.PathError:
-			// from parser
-			errs = append(errs, Error{
-				Pos:  err.Path + ":1",
-				Msg:  err.Err.Error(),
-				Kind: ParseError,
-			})
-
-		case scanner.ErrorList:
-			// from parser
-			for _, err := range err {
-				errs = append(errs, Error{
-					Pos:  err.Pos.String(),
-					Msg:  err.Msg,
-					Kind: ParseError,
-				})
-			}
-
-		case types.Error:
-			// from type checker
-			errs = append(errs, Error{
-				Pos:  err.Fset.Position(err.Pos).String(),
-				Msg:  err.Msg,
-				Kind: TypeError,
-			})
-
-		default:
-			// unexpected impoverished error from parser?
-			errs = append(errs, Error{
-				Pos:  "-",
-				Msg:  err.Error(),
-				Kind: UnknownError,
-			})
-
-			// If you see this error message, please file a bug.
-			log.Printf("internal error: error %q (%T) without position", err, err)
-		}
-
-		lpkg.Errors = append(lpkg.Errors, errs...)
-	}
-
-	if ld.Config.Mode&NeedTypes != 0 && len(lpkg.CompiledGoFiles) == 0 && lpkg.ExportFile != "" {
-		// The config requested loading sources and types, but sources are missing.
-		// Add an error to the package and fall back to loading from export data.
-		appendError(Error{"-", fmt.Sprintf("sources missing for package %s", lpkg.ID), ParseError})
-		ld.loadFromExportData(lpkg)
-		return // can't get syntax trees for this package
-	}
-
-	files, errs := ld.parseFiles(lpkg.CompiledGoFiles)
-	for _, err := range errs {
-		appendError(err)
-	}
-
-	lpkg.Syntax = files
-	if ld.Config.Mode&NeedTypes == 0 {
-		return
-	}
-
-	lpkg.TypesInfo = &types.Info{
-		Types:      make(map[ast.Expr]types.TypeAndValue),
-		Defs:       make(map[*ast.Ident]types.Object),
-		Uses:       make(map[*ast.Ident]types.Object),
-		Implicits:  make(map[ast.Node]types.Object),
-		Scopes:     make(map[ast.Node]*types.Scope),
-		Selections: make(map[*ast.SelectorExpr]*types.Selection),
-	}
-	lpkg.TypesSizes = ld.sizes
-
-	importer := importerFunc(func(path string) (*types.Package, error) {
-		if path == "unsafe" {
-			return types.Unsafe, nil
-		}
-
-		// The imports map is keyed by import path.
-		ipkg := lpkg.Imports[path]
-		if ipkg == nil {
-			if err := lpkg.importErrors[path]; err != nil {
-				return nil, err
-			}
-			// There was skew between the metadata and the
-			// import declarations, likely due to an edit
-			// race, or because the ParseFile feature was
-			// used to supply alternative file contents.
-			return nil, fmt.Errorf("no metadata for %s", path)
-		}
-
-		if ipkg.Types != nil && ipkg.Types.Complete() {
-			return ipkg.Types, nil
-		}
-		log.Fatalf("internal error: package %q without types was imported from %q", path, lpkg)
-		panic("unreachable")
-	})
-
-	// type-check
-	tc := &types.Config{
-		Importer: importer,
-
-		// Type-check bodies of functions only in non-initial packages.
-		// Example: for import graph A->B->C and initial packages {A,C},
-		// we can ignore function bodies in B.
-		IgnoreFuncBodies: ld.Mode&NeedDeps == 0 && !lpkg.initial,
-
-		Error: appendError,
-		Sizes: ld.sizes,
-	}
-	if (ld.Mode & typecheckCgo) != 0 {
-		if !typesinternal.SetUsesCgo(tc) {
-			appendError(Error{
-				Msg:  "typecheckCgo requires Go 1.15+",
-				Kind: ListError,
-			})
-			return
-		}
-	}
-	types.NewChecker(tc, ld.Fset, lpkg.Types, lpkg.TypesInfo).Files(lpkg.Syntax)
-
-	lpkg.importErrors = nil // no longer needed
-
-	// If !Cgo, the type-checker uses FakeImportC mode, so
-	// it doesn't invoke the importer for import "C",
-	// nor report an error for the import,
-	// or for any undefined C.f reference.
-	// We must detect this explicitly and correctly
-	// mark the package as IllTyped (by reporting an error).
-	// TODO(adonovan): if these errors are annoying,
-	// we could just set IllTyped quietly.
-	if tc.FakeImportC {
-	outer:
-		for _, f := range lpkg.Syntax {
-			for _, imp := range f.Imports {
-				if imp.Path.Value == `"C"` {
-					err := types.Error{Fset: ld.Fset, Pos: imp.Pos(), Msg: `import "C" ignored`}
-					appendError(err)
-					break outer
-				}
-			}
-		}
-	}
-
-	// Record accumulated errors.
-	illTyped := len(lpkg.Errors) > 0
-	if !illTyped {
-		for _, imp := range lpkg.Imports {
-			if imp.IllTyped {
-				illTyped = true
-				break
-			}
-		}
-	}
-	lpkg.IllTyped = illTyped
-}
-
-// An importFunc is an implementation of the single-method
-// types.Importer interface based on a function value.
-type importerFunc func(path string) (*types.Package, error)
-
-func (f importerFunc) Import(path string) (*types.Package, error) { return f(path) }
-
-// We use a counting semaphore to limit
-// the number of parallel I/O calls per process.
-var ioLimit = make(chan bool, 20)
-
-func (ld *loader) parseFile(filename string) (*ast.File, error) {
-	ld.parseCacheMu.Lock()
-	v, ok := ld.parseCache[filename]
-	if ok {
-		// cache hit
-		ld.parseCacheMu.Unlock()
-		<-v.ready
-	} else {
-		// cache miss
-		v = &parseValue{ready: make(chan struct{})}
-		ld.parseCache[filename] = v
-		ld.parseCacheMu.Unlock()
-
-		var src []byte
-		for f, contents := range ld.Config.Overlay {
-			if sameFile(f, filename) {
-				src = contents
-			}
-		}
-		var err error
-		if src == nil {
-			ioLimit <- true // wait
-			src, err = ioutil.ReadFile(filename)
-			<-ioLimit // signal
-		}
-		if err != nil {
-			v.err = err
-		} else {
-			v.f, v.err = ld.ParseFile(ld.Fset, filename, src)
-		}
-
-		close(v.ready)
-	}
-	return v.f, v.err
-}
-
-// parseFiles reads and parses the Go source files and returns the ASTs
-// of the ones that could be at least partially parsed, along with a
-// list of I/O and parse errors encountered.
-//
-// Because files are scanned in parallel, the token.Pos
-// positions of the resulting ast.Files are not ordered.
-//
-func (ld *loader) parseFiles(filenames []string) ([]*ast.File, []error) {
-	var wg sync.WaitGroup
-	n := len(filenames)
-	parsed := make([]*ast.File, n)
-	errors := make([]error, n)
-	for i, file := range filenames {
-		if ld.Config.Context.Err() != nil {
-			parsed[i] = nil
-			errors[i] = ld.Config.Context.Err()
-			continue
-		}
-		wg.Add(1)
-		go func(i int, filename string) {
-			parsed[i], errors[i] = ld.parseFile(filename)
-			wg.Done()
-		}(i, file)
-	}
-	wg.Wait()
-
-	// Eliminate nils, preserving order.
-	var o int
-	for _, f := range parsed {
-		if f != nil {
-			parsed[o] = f
-			o++
-		}
-	}
-	parsed = parsed[:o]
-
-	o = 0
-	for _, err := range errors {
-		if err != nil {
-			errors[o] = err
-			o++
-		}
-	}
-	errors = errors[:o]
-
-	return parsed, errors
-}
-
-// sameFile returns true if x and y have the same basename and denote
-// the same file.
-//
-func sameFile(x, y string) bool {
-	if x == y {
-		// It could be the case that y doesn't exist.
-		// For instance, it may be an overlay file that
-		// hasn't been written to disk. To handle that case
-		// let x == y through. (We added the exact absolute path
-		// string to the CompiledGoFiles list, so the unwritten
-		// overlay case implies x==y.)
-		return true
-	}
-	if strings.EqualFold(filepath.Base(x), filepath.Base(y)) { // (optimisation)
-		if xi, err := os.Stat(x); err == nil {
-			if yi, err := os.Stat(y); err == nil {
-				return os.SameFile(xi, yi)
-			}
-		}
-	}
-	return false
-}
-
-// loadFromExportData returns type information for the specified
-// package, loading it from an export data file on the first request.
-func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error) {
-	if lpkg.PkgPath == "" {
-		log.Fatalf("internal error: Package %s has no PkgPath", lpkg)
-	}
-
-	// Because gcexportdata.Read has the potential to create or
-	// modify the types.Package for each node in the transitive
-	// closure of dependencies of lpkg, all exportdata operations
-	// must be sequential. (Finer-grained locking would require
-	// changes to the gcexportdata API.)
-	//
-	// The exportMu lock guards the Package.Pkg field and the
-	// types.Package it points to, for each Package in the graph.
-	//
-	// Not all accesses to Package.Pkg need to be protected by exportMu:
-	// graph ordering ensures that direct dependencies of source
-	// packages are fully loaded before the importer reads their Pkg field.
-	ld.exportMu.Lock()
-	defer ld.exportMu.Unlock()
-
-	if tpkg := lpkg.Types; tpkg != nil && tpkg.Complete() {
-		return tpkg, nil // cache hit
-	}
-
-	lpkg.IllTyped = true // fail safe
-
-	if lpkg.ExportFile == "" {
-		// Errors while building export data will have been printed to stderr.
-		return nil, fmt.Errorf("no export data file")
-	}
-	f, err := os.Open(lpkg.ExportFile)
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	// Read gc export data.
-	//
-	// We don't currently support gccgo export data because all
-	// underlying workspaces use the gc toolchain. (Even build
-	// systems that support gccgo don't use it for workspace
-	// queries.)
-	r, err := gcexportdata.NewReader(f)
-	if err != nil {
-		return nil, fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
-	}
-
-	// Build the view.
-	//
-	// The gcexportdata machinery has no concept of package ID.
-	// It identifies packages by their PkgPath, which although not
-	// globally unique is unique within the scope of one invocation
-	// of the linker, type-checker, or gcexportdata.
-	//
-	// So, we must build a PkgPath-keyed view of the global
-	// (conceptually ID-keyed) cache of packages and pass it to
-	// gcexportdata. The view must contain every existing
-	// package that might possibly be mentioned by the
-	// current package---its transitive closure.
-	//
-	// In loadPackage, we unconditionally create a types.Package for
-	// each dependency so that export data loading does not
-	// create new ones.
-	//
-	// TODO(adonovan): it would be simpler and more efficient
-	// if the export data machinery invoked a callback to
-	// get-or-create a package instead of a map.
-	//
-	view := make(map[string]*types.Package) // view seen by gcexportdata
-	seen := make(map[*loaderPackage]bool)   // all visited packages
-	var visit func(pkgs map[string]*Package)
-	visit = func(pkgs map[string]*Package) {
-		for _, p := range pkgs {
-			lpkg := ld.pkgs[p.ID]
-			if !seen[lpkg] {
-				seen[lpkg] = true
-				view[lpkg.PkgPath] = lpkg.Types
-				visit(lpkg.Imports)
-			}
-		}
-	}
-	visit(lpkg.Imports)
-
-	viewLen := len(view) + 1 // adding the self package
-	// Parse the export data.
-	// (May modify incomplete packages in view but not create new ones.)
-	tpkg, err := gcexportdata.Read(r, ld.Fset, view, lpkg.PkgPath)
-	if err != nil {
-		return nil, fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
-	}
-	if viewLen != len(view) {
-		log.Fatalf("Unexpected package creation during export data loading")
-	}
-
-	lpkg.Types = tpkg
-	lpkg.IllTyped = false
-
-	return tpkg, nil
-}
-
-// impliedLoadMode returns loadMode with its dependencies.
-func impliedLoadMode(loadMode LoadMode) LoadMode {
-	if loadMode&NeedTypesInfo != 0 && loadMode&NeedImports == 0 {
-		// If NeedTypesInfo, go/packages needs to do typechecking itself so it can
-		// associate type info with the AST. To do so, we need the export data
-		// for dependencies, which means we need to ask for the direct dependencies.
-		// NeedImports is used to ask for the direct dependencies.
-		loadMode |= NeedImports
-	}
-
-	if loadMode&NeedDeps != 0 && loadMode&NeedImports == 0 {
-		// With NeedDeps we need to load at least direct dependencies.
-		// NeedImports is used to ask for the direct dependencies.
-		loadMode |= NeedImports
-	}
-
-	return loadMode
-}
-
-func usesExportData(cfg *Config) bool {
-	return cfg.Mode&NeedExportsFile != 0 || cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedDeps == 0
-}
diff --git a/vendor/golang.org/x/tools/go/packages/visit.go b/vendor/golang.org/x/tools/go/packages/visit.go
deleted file mode 100644
index a1dcc40b72..0000000000
--- a/vendor/golang.org/x/tools/go/packages/visit.go
+++ /dev/null
@@ -1,59 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package packages
-
-import (
-	"fmt"
-	"os"
-	"sort"
-)
-
-// Visit visits all the packages in the import graph whose roots are
-// pkgs, calling the optional pre function the first time each package
-// is encountered (preorder), and the optional post function after a
-// package's dependencies have been visited (postorder).
-// The boolean result of pre(pkg) determines whether
-// the imports of package pkg are visited.
-func Visit(pkgs []*Package, pre func(*Package) bool, post func(*Package)) {
-	seen := make(map[*Package]bool)
-	var visit func(*Package)
-	visit = func(pkg *Package) {
-		if !seen[pkg] {
-			seen[pkg] = true
-
-			if pre == nil || pre(pkg) {
-				paths := make([]string, 0, len(pkg.Imports))
-				for path := range pkg.Imports {
-					paths = append(paths, path)
-				}
-				sort.Strings(paths) // Imports is a map, this makes visit stable
-				for _, path := range paths {
-					visit(pkg.Imports[path])
-				}
-			}
-
-			if post != nil {
-				post(pkg)
-			}
-		}
-	}
-	for _, pkg := range pkgs {
-		visit(pkg)
-	}
-}
-
-// PrintErrors prints to os.Stderr the accumulated errors of all
-// packages in the import graph rooted at pkgs, dependencies first.
-// PrintErrors returns the number of errors printed.
-func PrintErrors(pkgs []*Package) int {
-	var n int
-	Visit(pkgs, nil, func(pkg *Package) {
-		for _, err := range pkg.Errors {
-			fmt.Fprintln(os.Stderr, err)
-			n++
-		}
-	})
-	return n
-}
diff --git a/vendor/golang.org/x/tools/go/types/objectpath/objectpath.go b/vendor/golang.org/x/tools/go/types/objectpath/objectpath.go
deleted file mode 100644
index cffd7acbee..0000000000
--- a/vendor/golang.org/x/tools/go/types/objectpath/objectpath.go
+++ /dev/null
@@ -1,524 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package objectpath defines a naming scheme for types.Objects
-// (that is, named entities in Go programs) relative to their enclosing
-// package.
-//
-// Type-checker objects are canonical, so they are usually identified by
-// their address in memory (a pointer), but a pointer has meaning only
-// within one address space. By contrast, objectpath names allow the
-// identity of an object to be sent from one program to another,
-// establishing a correspondence between types.Object variables that are
-// distinct but logically equivalent.
-//
-// A single object may have multiple paths. In this example,
-//     type A struct{ X int }
-//     type B A
-// the field X has two paths due to its membership of both A and B.
-// The For(obj) function always returns one of these paths, arbitrarily
-// but consistently.
-package objectpath
-
-import (
-	"fmt"
-	"strconv"
-	"strings"
-
-	"go/types"
-)
-
-// A Path is an opaque name that identifies a types.Object
-// relative to its package. Conceptually, the name consists of a
-// sequence of destructuring operations applied to the package scope
-// to obtain the original object.
-// The name does not include the package itself.
-type Path string
-
-// Encoding
-//
-// An object path is a textual and (with training) human-readable encoding
-// of a sequence of destructuring operators, starting from a types.Package.
-// The sequences represent a path through the package/object/type graph.
-// We classify these operators by their type:
-//
-//   PO package->object	Package.Scope.Lookup
-//   OT  object->type 	Object.Type
-//   TT    type->type 	Type.{Elem,Key,Params,Results,Underlying} [EKPRU]
-//   TO   type->object	Type.{At,Field,Method,Obj} [AFMO]
-//
-// All valid paths start with a package and end at an object
-// and thus may be defined by the regular language:
-//
-//   objectpath = PO (OT TT* TO)*
-//
-// The concrete encoding follows directly:
-// - The only PO operator is Package.Scope.Lookup, which requires an identifier.
-// - The only OT operator is Object.Type,
-//   which we encode as '.' because dot cannot appear in an identifier.
-// - The TT operators are encoded as [EKPRU].
-// - The OT operators are encoded as [AFMO];
-//   three of these (At,Field,Method) require an integer operand,
-//   which is encoded as a string of decimal digits.
-//   These indices are stable across different representations
-//   of the same package, even source and export data.
-//
-// In the example below,
-//
-//	package p
-//
-//	type T interface {
-//		f() (a string, b struct{ X int })
-//	}
-//
-// field X has the path "T.UM0.RA1.F0",
-// representing the following sequence of operations:
-//
-//    p.Lookup("T")					T
-//    .Type().Underlying().Method(0).			f
-//    .Type().Results().At(1)				b
-//    .Type().Field(0)					X
-//
-// The encoding is not maximally compact---every R or P is
-// followed by an A, for example---but this simplifies the
-// encoder and decoder.
-//
-const (
-	// object->type operators
-	opType = '.' // .Type()		  (Object)
-
-	// type->type operators
-	opElem       = 'E' // .Elem()		(Pointer, Slice, Array, Chan, Map)
-	opKey        = 'K' // .Key()		(Map)
-	opParams     = 'P' // .Params()		(Signature)
-	opResults    = 'R' // .Results()	(Signature)
-	opUnderlying = 'U' // .Underlying()	(Named)
-
-	// type->object operators
-	opAt     = 'A' // .At(i)		(Tuple)
-	opField  = 'F' // .Field(i)		(Struct)
-	opMethod = 'M' // .Method(i)		(Named or Interface; not Struct: "promoted" names are ignored)
-	opObj    = 'O' // .Obj()		(Named)
-)
-
-// The For function returns the path to an object relative to its package,
-// or an error if the object is not accessible from the package's Scope.
-//
-// The For function guarantees to return a path only for the following objects:
-// - package-level types
-// - exported package-level non-types
-// - methods
-// - parameter and result variables
-// - struct fields
-// These objects are sufficient to define the API of their package.
-// The objects described by a package's export data are drawn from this set.
-//
-// For does not return a path for predeclared names, imported package
-// names, local names, and unexported package-level names (except
-// types).
-//
-// Example: given this definition,
-//
-//	package p
-//
-//	type T interface {
-//		f() (a string, b struct{ X int })
-//	}
-//
-// For(X) would return a path that denotes the following sequence of operations:
-//
-//    p.Scope().Lookup("T")				(TypeName T)
-//    .Type().Underlying().Method(0).			(method Func f)
-//    .Type().Results().At(1)				(field Var b)
-//    .Type().Field(0)					(field Var X)
-//
-// where p is the package (*types.Package) to which X belongs.
-func For(obj types.Object) (Path, error) {
-	pkg := obj.Pkg()
-
-	// This table lists the cases of interest.
-	//
-	// Object				Action
-	// ------                               ------
-	// nil					reject
-	// builtin				reject
-	// pkgname				reject
-	// label				reject
-	// var
-	//    package-level			accept
-	//    func param/result			accept
-	//    local				reject
-	//    struct field			accept
-	// const
-	//    package-level			accept
-	//    local				reject
-	// func
-	//    package-level			accept
-	//    init functions			reject
-	//    concrete method			accept
-	//    interface method			accept
-	// type
-	//    package-level			accept
-	//    local				reject
-	//
-	// The only accessible package-level objects are members of pkg itself.
-	//
-	// The cases are handled in four steps:
-	//
-	// 1. reject nil and builtin
-	// 2. accept package-level objects
-	// 3. reject obviously invalid objects
-	// 4. search the API for the path to the param/result/field/method.
-
-	// 1. reference to nil or builtin?
-	if pkg == nil {
-		return "", fmt.Errorf("predeclared %s has no path", obj)
-	}
-	scope := pkg.Scope()
-
-	// 2. package-level object?
-	if scope.Lookup(obj.Name()) == obj {
-		// Only exported objects (and non-exported types) have a path.
-		// Non-exported types may be referenced by other objects.
-		if _, ok := obj.(*types.TypeName); !ok && !obj.Exported() {
-			return "", fmt.Errorf("no path for non-exported %v", obj)
-		}
-		return Path(obj.Name()), nil
-	}
-
-	// 3. Not a package-level object.
-	//    Reject obviously non-viable cases.
-	switch obj := obj.(type) {
-	case *types.Const, // Only package-level constants have a path.
-		*types.TypeName, // Only package-level types have a path.
-		*types.Label,    // Labels are function-local.
-		*types.PkgName:  // PkgNames are file-local.
-		return "", fmt.Errorf("no path for %v", obj)
-
-	case *types.Var:
-		// Could be:
-		// - a field (obj.IsField())
-		// - a func parameter or result
-		// - a local var.
-		// Sadly there is no way to distinguish
-		// a param/result from a local
-		// so we must proceed to the find.
-
-	case *types.Func:
-		// A func, if not package-level, must be a method.
-		if recv := obj.Type().(*types.Signature).Recv(); recv == nil {
-			return "", fmt.Errorf("func is not a method: %v", obj)
-		}
-		// TODO(adonovan): opt: if the method is concrete,
-		// do a specialized version of the rest of this function so
-		// that it's O(1) not O(|scope|).  Basically 'find' is needed
-		// only for struct fields and interface methods.
-
-	default:
-		panic(obj)
-	}
-
-	// 4. Search the API for the path to the var (field/param/result) or method.
-
-	// First inspect package-level named types.
-	// In the presence of path aliases, these give
-	// the best paths because non-types may
-	// refer to types, but not the reverse.
-	empty := make([]byte, 0, 48) // initial space
-	names := scope.Names()
-	for _, name := range names {
-		o := scope.Lookup(name)
-		tname, ok := o.(*types.TypeName)
-		if !ok {
-			continue // handle non-types in second pass
-		}
-
-		path := append(empty, name...)
-		path = append(path, opType)
-
-		T := o.Type()
-
-		if tname.IsAlias() {
-			// type alias
-			if r := find(obj, T, path); r != nil {
-				return Path(r), nil
-			}
-		} else {
-			// defined (named) type
-			if r := find(obj, T.Underlying(), append(path, opUnderlying)); r != nil {
-				return Path(r), nil
-			}
-		}
-	}
-
-	// Then inspect everything else:
-	// non-types, and declared methods of defined types.
-	for _, name := range names {
-		o := scope.Lookup(name)
-		path := append(empty, name...)
-		if _, ok := o.(*types.TypeName); !ok {
-			if o.Exported() {
-				// exported non-type (const, var, func)
-				if r := find(obj, o.Type(), append(path, opType)); r != nil {
-					return Path(r), nil
-				}
-			}
-			continue
-		}
-
-		// Inspect declared methods of defined types.
-		if T, ok := o.Type().(*types.Named); ok {
-			path = append(path, opType)
-			for i := 0; i < T.NumMethods(); i++ {
-				m := T.Method(i)
-				path2 := appendOpArg(path, opMethod, i)
-				if m == obj {
-					return Path(path2), nil // found declared method
-				}
-				if r := find(obj, m.Type(), append(path2, opType)); r != nil {
-					return Path(r), nil
-				}
-			}
-		}
-	}
-
-	return "", fmt.Errorf("can't find path for %v in %s", obj, pkg.Path())
-}
-
-func appendOpArg(path []byte, op byte, arg int) []byte {
-	path = append(path, op)
-	path = strconv.AppendInt(path, int64(arg), 10)
-	return path
-}
-
-// find finds obj within type T, returning the path to it, or nil if not found.
-func find(obj types.Object, T types.Type, path []byte) []byte {
-	switch T := T.(type) {
-	case *types.Basic, *types.Named:
-		// Named types belonging to pkg were handled already,
-		// so T must belong to another package. No path.
-		return nil
-	case *types.Pointer:
-		return find(obj, T.Elem(), append(path, opElem))
-	case *types.Slice:
-		return find(obj, T.Elem(), append(path, opElem))
-	case *types.Array:
-		return find(obj, T.Elem(), append(path, opElem))
-	case *types.Chan:
-		return find(obj, T.Elem(), append(path, opElem))
-	case *types.Map:
-		if r := find(obj, T.Key(), append(path, opKey)); r != nil {
-			return r
-		}
-		return find(obj, T.Elem(), append(path, opElem))
-	case *types.Signature:
-		if r := find(obj, T.Params(), append(path, opParams)); r != nil {
-			return r
-		}
-		return find(obj, T.Results(), append(path, opResults))
-	case *types.Struct:
-		for i := 0; i < T.NumFields(); i++ {
-			f := T.Field(i)
-			path2 := appendOpArg(path, opField, i)
-			if f == obj {
-				return path2 // found field var
-			}
-			if r := find(obj, f.Type(), append(path2, opType)); r != nil {
-				return r
-			}
-		}
-		return nil
-	case *types.Tuple:
-		for i := 0; i < T.Len(); i++ {
-			v := T.At(i)
-			path2 := appendOpArg(path, opAt, i)
-			if v == obj {
-				return path2 // found param/result var
-			}
-			if r := find(obj, v.Type(), append(path2, opType)); r != nil {
-				return r
-			}
-		}
-		return nil
-	case *types.Interface:
-		for i := 0; i < T.NumMethods(); i++ {
-			m := T.Method(i)
-			path2 := appendOpArg(path, opMethod, i)
-			if m == obj {
-				return path2 // found interface method
-			}
-			if r := find(obj, m.Type(), append(path2, opType)); r != nil {
-				return r
-			}
-		}
-		return nil
-	}
-	panic(T)
-}
-
-// Object returns the object denoted by path p within the package pkg.
-func Object(pkg *types.Package, p Path) (types.Object, error) {
-	if p == "" {
-		return nil, fmt.Errorf("empty path")
-	}
-
-	pathstr := string(p)
-	var pkgobj, suffix string
-	if dot := strings.IndexByte(pathstr, opType); dot < 0 {
-		pkgobj = pathstr
-	} else {
-		pkgobj = pathstr[:dot]
-		suffix = pathstr[dot:] // suffix starts with "."
-	}
-
-	obj := pkg.Scope().Lookup(pkgobj)
-	if obj == nil {
-		return nil, fmt.Errorf("package %s does not contain %q", pkg.Path(), pkgobj)
-	}
-
-	// abstraction of *types.{Pointer,Slice,Array,Chan,Map}
-	type hasElem interface {
-		Elem() types.Type
-	}
-	// abstraction of *types.{Interface,Named}
-	type hasMethods interface {
-		Method(int) *types.Func
-		NumMethods() int
-	}
-
-	// The loop state is the pair (t, obj),
-	// exactly one of which is non-nil, initially obj.
-	// All suffixes start with '.' (the only object->type operation),
-	// followed by optional type->type operations,
-	// then a type->object operation.
-	// The cycle then repeats.
-	var t types.Type
-	for suffix != "" {
-		code := suffix[0]
-		suffix = suffix[1:]
-
-		// Codes [AFM] have an integer operand.
-		var index int
-		switch code {
-		case opAt, opField, opMethod:
-			rest := strings.TrimLeft(suffix, "0123456789")
-			numerals := suffix[:len(suffix)-len(rest)]
-			suffix = rest
-			i, err := strconv.Atoi(numerals)
-			if err != nil {
-				return nil, fmt.Errorf("invalid path: bad numeric operand %q for code %q", numerals, code)
-			}
-			index = int(i)
-		case opObj:
-			// no operand
-		default:
-			// The suffix must end with a type->object operation.
-			if suffix == "" {
-				return nil, fmt.Errorf("invalid path: ends with %q, want [AFMO]", code)
-			}
-		}
-
-		if code == opType {
-			if t != nil {
-				return nil, fmt.Errorf("invalid path: unexpected %q in type context", opType)
-			}
-			t = obj.Type()
-			obj = nil
-			continue
-		}
-
-		if t == nil {
-			return nil, fmt.Errorf("invalid path: code %q in object context", code)
-		}
-
-		// Inv: t != nil, obj == nil
-
-		switch code {
-		case opElem:
-			hasElem, ok := t.(hasElem) // Pointer, Slice, Array, Chan, Map
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %T, want pointer, slice, array, chan or map)", code, t, t)
-			}
-			t = hasElem.Elem()
-
-		case opKey:
-			mapType, ok := t.(*types.Map)
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %T, want map)", code, t, t)
-			}
-			t = mapType.Key()
-
-		case opParams:
-			sig, ok := t.(*types.Signature)
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %T, want signature)", code, t, t)
-			}
-			t = sig.Params()
-
-		case opResults:
-			sig, ok := t.(*types.Signature)
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %T, want signature)", code, t, t)
-			}
-			t = sig.Results()
-
-		case opUnderlying:
-			named, ok := t.(*types.Named)
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %s, want named)", code, t, t)
-			}
-			t = named.Underlying()
-
-		case opAt:
-			tuple, ok := t.(*types.Tuple)
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %s, want tuple)", code, t, t)
-			}
-			if n := tuple.Len(); index >= n {
-				return nil, fmt.Errorf("tuple index %d out of range [0-%d)", index, n)
-			}
-			obj = tuple.At(index)
-			t = nil
-
-		case opField:
-			structType, ok := t.(*types.Struct)
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %T, want struct)", code, t, t)
-			}
-			if n := structType.NumFields(); index >= n {
-				return nil, fmt.Errorf("field index %d out of range [0-%d)", index, n)
-			}
-			obj = structType.Field(index)
-			t = nil
-
-		case opMethod:
-			hasMethods, ok := t.(hasMethods) // Interface or Named
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %s, want interface or named)", code, t, t)
-			}
-			if n := hasMethods.NumMethods(); index >= n {
-				return nil, fmt.Errorf("method index %d out of range [0-%d)", index, n)
-			}
-			obj = hasMethods.Method(index)
-			t = nil
-
-		case opObj:
-			named, ok := t.(*types.Named)
-			if !ok {
-				return nil, fmt.Errorf("cannot apply %q to %s (got %s, want named)", code, t, t)
-			}
-			obj = named.Obj()
-			t = nil
-
-		default:
-			return nil, fmt.Errorf("invalid path: unknown code %q", code)
-		}
-	}
-
-	if obj.Pkg() != pkg {
-		return nil, fmt.Errorf("path denotes %s, which belongs to a different package", obj)
-	}
-
-	return obj, nil // success
-}