Add the first few Java 19 tests

For now, only the "pattern matching for switch" tests from previews 1
and 2 were adjusted to work in preview 3, because guarded patterns were
replaced by 'when' clauses in 'switch' blocks. Therefore, existing test
classes did not compile anymore and had to be replaced by syntactically
upgraded versions with content merged from preview 1 and 2 classes.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

4 files changed, 294 insertions, 0 deletions

diff --git a/tests/features1919/java19/SwitchPatternPreview3Aspect.aj b/tests/features1919/java19/SwitchPatternPreview3Aspect.aj
new file mode 100644
index 000000000..ae147dad7
--- /dev/null
+++ b/tests/features1919/java19/SwitchPatternPreview3Aspect.aj
@@ -0,0 +1,88 @@
+import java.util.List;
+import java.util.Locale;
+
+aspect SwitchPatternPreview3Aspect {
+  Object around(Object o) : execution(* doSomethingWithObject(*)) && args(o) {
+    System.out.println(switch (o) {
+      case null      -> "null";
+      case Integer i -> String.format("int %d", i);
+      case Long l    -> String.format("long %d", l);
+      case Double d  -> String.format(Locale.ENGLISH, "double %f", d);
+      case String s  -> String.format("String %s", s);
+      default        -> o.toString();
+    });
+    return proceed(o);
+  }
+
+  before(Shape s) : execution(* doSomethingWithShape(*)) && args(s) {
+    System.out.println(switch (s) {
+      case Circle c when (c.calculateArea() > 100) -> "Large circle";
+      case Circle c -> "Small circle";
+      default -> "Non-circle";
+    });
+  }
+
+  after(S s) : execution(* doSomethingWithSealedClass(*)) && args(s) {
+    System.out.println(switch (s) {
+      case A a -> "Sealed sub-class A";
+      case B b -> "Sealed sub-class B";
+      case C c -> "Sealed sub-record C";
+    });
+  }
+
+  Object around(Integer i): execution(* doSomethingWithInteger(*)) && args(i) {
+    System.out.println(
+      switch (i) {
+        case null -> "value unavailable: " + i;
+        case -1, 1 -> "absolute value 1: " + i;
+        case Integer value when value > 0 -> "positive integer: " + i;
+        default -> "other integer: " + i;
+      }
+    );
+    return proceed(i);
+  }
+}
+
+class Shape {}
+class Rectangle extends Shape {}
+class Circle extends Shape {
+  private final double radius;
+  public Circle(double radius) { this.radius = radius; }
+  double calculateArea() { return Math.PI * radius * radius; }
+}
+
+sealed interface S permits A, B, C {}
+final class A implements S {}
+final class B implements S {}
+record C(int i) implements S {}  // Implicitly final
+
+class Application {
+  public static void main(String[] args) {
+    doSomethingWithObject(null);
+    doSomethingWithObject(123);
+    doSomethingWithObject(999L);
+    doSomethingWithObject(12.34);
+    doSomethingWithObject("foo");
+    doSomethingWithObject(List.of(123, "foo", 999L, 12.34));
+
+    doSomethingWithShape(new Rectangle());
+    doSomethingWithShape(new Circle(5));
+    doSomethingWithShape(new Circle(6));
+
+    doSomethingWithSealedClass(new A());
+    doSomethingWithSealedClass(new B());
+    doSomethingWithSealedClass(new C(5));
+
+    doSomethingWithInteger(-1);
+    doSomethingWithInteger(0);
+    doSomethingWithInteger(42);
+    doSomethingWithInteger(-99);
+    doSomethingWithInteger(Integer.valueOf(123));
+    doSomethingWithInteger(null);
+  }
+
+  public static Object doSomethingWithObject(Object o) { return o; }
+  public static void doSomethingWithSealedClass(S s) {}
+  public static void doSomethingWithShape(Shape s) {}
+  public static Object doSomethingWithInteger(Integer o) { return o; }
+}
diff --git a/tests/features1919/java19/SwitchPatternPreview3Error1.java b/tests/features1919/java19/SwitchPatternPreview3Error1.java
new file mode 100644
index 000000000..5f3895cc3
--- /dev/null
+++ b/tests/features1919/java19/SwitchPatternPreview3Error1.java
@@ -0,0 +1,13 @@
+/**
+ * Inspired by examples in https://openjdk.java.net/jeps/420
+ */
+public class SwitchPatternPreview3Error1 {
+  static void constantLabelsMustAppearBeforePatterns1(Integer i) {
+    switch (i) {
+      case null -> System.out.println("value unavailable: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      default -> System.out.println("other integer: " + i);
+    }
+  }
+}
diff --git a/tests/features1919/java19/SwitchPatternPreview3Error2.java b/tests/features1919/java19/SwitchPatternPreview3Error2.java
new file mode 100644
index 000000000..c02c4d3cc
--- /dev/null
+++ b/tests/features1919/java19/SwitchPatternPreview3Error2.java
@@ -0,0 +1,21 @@
+/**
+ * Inspired by examples in https://openjdk.java.net/jeps/420
+ */
+public class SwitchPatternPreview3Error2 {
+  static void constantLabelsMustAppearBeforePatterns2(Object o) {
+    switch (o) {
+      case null -> System.out.println("value unavailable: " + o);
+      // This seems to be a bug in JEP 420 implementation. Those constants should be compatible with 'Object'.
+      // case -1, 1 -> System.out.println("absolute value 1: " + o);
+      // case "hello" -> System.out.println("string value: " + o);
+
+      // 'Integer value' dominates the next two, more specific ones -> error
+      case Integer value -> System.out.println("other integer: " + o);
+      case Integer value when (value == 1 || value == -1) -> System.out.println("absolute value 1: " + o);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + o);
+
+      case String value when value.startsWith("hello") -> System.out.println("greeting: " + o);
+      default -> System.out.println("other type: " + o);
+    }
+  }
+}
diff --git a/tests/features1919/java19/SwitchPatternPreview3OK.java b/tests/features1919/java19/SwitchPatternPreview3OK.java
new file mode 100644
index 000000000..7060ec0c2
--- /dev/null
+++ b/tests/features1919/java19/SwitchPatternPreview3OK.java
@@ -0,0 +1,172 @@
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Inspired by examples in https://openjdk.org/jeps/427
+ */
+public class SwitchPatternPreview3OK {
+  public static void main(String[] args) {
+
+    System.out.println(formatterPatternSwitch(null));
+    System.out.println(formatterPatternSwitch(123));
+    System.out.println(formatterPatternSwitch(999L));
+    System.out.println(formatterPatternSwitch(12.34));
+    System.out.println(formatterPatternSwitch("foo"));
+    System.out.println(formatterPatternSwitch(List.of(123, "foo", 999L, 12.34)));
+
+    System.out.println(testCircle(new Rectangle()));
+    System.out.println(testCircle(new Circle(5)));
+    System.out.println(testCircle(new Circle(6)));
+
+    System.out.println(testSealedCoverage(new A()));
+    System.out.println(testSealedCoverage(new B()));
+    System.out.println(testSealedCoverage(new C(5)));
+
+//    constantLabelMustAppearBeforePattern(-1);
+//    constantLabelMustAppearBeforePattern(0);
+//    constantLabelMustAppearBeforePattern(42);
+//    constantLabelMustAppearBeforePattern(-99);
+//    constantLabelMustAppearBeforePattern(Integer.valueOf(123));
+//    constantLabelMustAppearBeforePattern(null);
+
+    constantLabelMustAppearBeforePatternInteger(-1);
+    constantLabelMustAppearBeforePatternInteger(0);
+    constantLabelMustAppearBeforePatternInteger(42);
+    constantLabelMustAppearBeforePatternInteger(-99);
+    constantLabelMustAppearBeforePatternInteger(Integer.valueOf(123));
+    constantLabelMustAppearBeforePatternInteger(null);
+
+//    System.out.println(testGenericSealedExhaustive(new B<Integer>()));
+  }
+
+  static String formatterPatternSwitch(Object o) {
+    return switch (o) {
+      case null      -> "null";
+      case Integer i -> String.format("int %d", i);
+      case Long l    -> String.format("long %d", l);
+      case Double d  -> String.format(Locale.ENGLISH, "double %f", d);
+      case String s  -> String.format("String %s", s);
+      default        -> o.toString();
+    };
+  }
+
+  static class Shape {}
+  static class Rectangle extends Shape {}
+  static class Circle extends Shape {
+    private final double radius;
+    public Circle(double radius) { this.radius = radius; }
+    double calculateArea() { return Math.PI * radius * radius; }
+  }
+
+  static String testCircle(Shape s) {
+    return switch (s) {
+      case Circle c when (c.calculateArea() > 100) -> "Large circle";
+      case Circle c -> "Small circle";
+      default -> "Non-circle";
+    };
+  }
+
+  sealed interface S permits A, B, C {}
+  final static class A implements S {}
+  final static class B implements S {}
+  static record C(int i) implements S {}  // Implicitly final
+
+  static String testSealedCoverage(S s) {
+    return switch (s) {
+      case A a -> "Sealed sub-class A";
+      case B b -> "Sealed sub-class B";
+      case C c -> "Sealed sub-record C";
+    };
+  }
+
+  /**
+   * According to an example from JEP 420, this should work, but it does not, neither with Javac nor ECJ.
+   *
+   * See:
+   *   https://openjdk.java.net/jeps/420#1b--Dominance-of-pattern-labels
+   *   https://bugs.openjdk.java.net/browse/JDK-8273326
+   *   https://bugs.eclipse.org/bugs/show_bug.cgi?id=579355
+   *
+   * TODO: reactivate when implemented or move to preview 3 with Java 19, Eclipse 4.24.
+   */
+  /*
+  static String constantLabelMustAppearBeforePattern(Object o) {
+    switch (o) {
+      case null -> System.out.println("value unavailable: " + i);
+      case -1, 1 -> System.out.println("special case:" + o);
+      case Integer i && i > 0 -> System.out.println("positive integer: " + o);
+      case Integer i -> System.out.println("other integer: " + o);
+      default -> System.out.println("non-integer: " + o);
+    }
+    return i == null ? "null" : i.toString();
+  }
+  */
+
+  static String constantLabelMustAppearBeforePatternInteger(Integer i) {
+    switch (i) {
+      case null -> System.out.println("value unavailable: " + i);
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+      default -> System.out.println("other integer: " + i);
+    }
+    return i == null ? "null" : i.toString();
+  }
+
+  static void nullCanAppearAfterConstantLabel(Integer i) {
+    switch (i) {
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      case null -> System.out.println("value unavailable: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+      default -> System.out.println("other integer: " + i);
+    }
+  }
+
+  static void defaultCanAppearBeforePattern(Integer i) {
+    switch (i) {
+      case null -> System.out.println("value unavailable: " + i);
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      default -> System.out.println("other integer: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+    }
+  }
+
+  static void defaultCanAppearBeforeNull(Integer i) {
+    switch (i) {
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      default -> System.out.println("other integer: " + i);
+      case null -> System.out.println("value unavailable: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+    }
+  }
+
+  static void defaultCanAppearBeforeConstantLabel(Integer i) {
+    switch (i) {
+      case null -> System.out.println("value unavailable: " + i);
+      default -> System.out.println("other integer: " + i);
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+    }
+  }
+
+  /**
+   * According to an example from JEP 420, this should work, and it does with Javac, but not with ECJ.
+   *
+   * See:
+   *   https://openjdk.java.net/jeps/420#2--Exhaustiveness-of-switch-expressions-and-statements
+   *   https://bugs.eclipse.org/bugs/show_bug.cgi?id=579360
+   *
+   * TODO: reactivate when implemented or move to preview 3 with Java 19, Eclipse 4.24.
+   */
+  /*
+  sealed interface I<T> permits A, B {}
+  final static class A<X> implements I<String> {}
+  final static class B<Y> implements I<Y> {}
+
+  static int testGenericSealedExhaustive(I<Integer> i) {
+    return switch (i) {
+      // Exhaustive as no A case possible!
+      case B<Integer> bi -> 42;
+    };
+  }
+  */
+}