Migrate language_2/metadata to NNBD.

Change-Id: I0243e6112ea3dc31e69a2c1395e08575ab5cb276
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149561
Auto-Submit: Bob Nystrom <rnystrom@google.com>
Commit-Queue: Erik Ernst <eernst@google.com>
Reviewed-by: Erik Ernst <eernst@google.com>

tests/language/metadata/cyclic_test.dart

@@ -0,0 +1,25 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Check that metadata on a class 'Super' using subtypes of 'Super' are not
+// considered as cyclic inheritance or lead to crashes.
+
+@Sub1(0) //# 01: ok
+class Super {
+  final field;
+  @Sub2(1) //# 02: ok
+  const Super(this.field);
+}
+
+class Sub1 extends Super {
+  const Sub1(var field) : super(field);
+}
+
+class Sub2 extends Super {
+  const Sub2(var field) : super(field);
+}
+
+void main() {
+  print(new Super(1));
+}

tests/language/metadata/lib.dart

@@ -0,0 +1,13 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library metadata.dart;
+
+class Alien {
+  final String qwrrkz;
+  const Alien(this.qwrrkz);
+  const Alien.unknown() : qwrrkz = "???";
+}
+
+const Klingon = const Alien("Klingon");

tests/language/metadata/metadata_test.dart

@@ -0,0 +1,62 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test ensuring that compiler can parse metadata. Need to add negative
+// test cases with illegal metadata annotations.
+
+library metadata_test.dart;
+
+import "package:expect/expect.dart";
+import "lib.dart" as Meta;
+
+class Tag {
+  final String annotation;
+  const Tag(this.annotation);
+}
+
+const meta1 = 1;
+const meta2 = const Tag("meta2");
+
+const extern = const Tag("external");
+
+@meta1
+var topLevelVar;
+@Meta.Alien.unknown()
+List unknownUnknowns = [];
+
+@meta1
+typedef int DingDong<@meta2 T>(@meta1 event);
+
+@meta1
+class A<@Tag("typeParam") T> {
+  @meta1
+  @meta2
+  static String staticField = "s";
+
+  @Meta.Alien("ET")
+  int foo(@meta1 bool fool, {@meta1 @Tag("opt") x: 100}) {
+    g() => 10;
+    return x * g();
+  }
+
+  @Tag(r"timewarp")
+  List<int> getNextWeeksLottoNumbers() => [1, 2, 3, 4, 5, 6];
+}
+
+@meta1
+main() {
+  @meta1
+  var a = new A();
+  Expect.equals(0, a.foo(false, x: 0));
+
+  for (@Tag("loopvar")
+  int i = 0;
+      i < 10;
+      i++) {
+    // Do something.
+  }
+
+  @meta1
+  var s = r'This is a raw \\ string.';
+}

tests/language/metadata/scope1_test.dart

@@ -0,0 +1,15 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test that a type variable is not in scope for metadata declared on the type
+// declaration.
+
+@deprecated
+typedef Foo
+<deprecated> // //# 01: ok
+    ();
+
+main() {
+  Foo? f = null;
+}

tests/language/metadata/scope2_test.dart

@@ -0,0 +1,15 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test that a type variable is not in scope for metadata declared on the type
+// declaration.
+
+@deprecated
+class Foo
+<deprecated> // //# 01: ok
+{}
+
+main() {
+  Foo? f = null;
+}

tests/language/metadata/self_test.dart

@@ -0,0 +1,14 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test that metadata refer to the annotated declaration.
+
+@Foo()
+class Foo {
+  const Foo();
+}
+
+main() {
+  Foo f = const Foo();
+}