Check for cyclic type variable bounds.

tests/compiler/dart2js/type_variable_bound_test.dart

Index: tests/compiler/dart2js/type_variable_bound_test.dart
diff --git a/tests/compiler/dart2js/type_variable_bound_test.dart b/tests/compiler/dart2js/type_variable_bound_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..6dd38a8a8e765734c260b52dc6c37e67b6e5370f
--- /dev/null
+++ b/tests/compiler/dart2js/type_variable_bound_test.dart
@@ -0,0 +1,116 @@
+// Copyright (c) 2013, 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.
+
+import 'compiler_helper.dart';
+import "package:expect/expect.dart";
+
+compile(String source) {
+  Uri uri = new Uri('test:code');
+  var compiler = compilerFor(source, uri);
+  compiler.runCompiler(uri);
+  return compiler;
+}
+
+test1() {
+  var compiler = compile(r"""
+class A<T extends T> {}
+
+void main() {
+  new A();
+}
+""");
+
+  Expect.isFalse(compiler.compilationFailed);
+  Expect.isTrue(compiler.errors.isEmpty,
+                'unexpected errors: ${compiler.errors}');
+  Expect.equals(1, compiler.warnings.length,
+                'expected exactly one warning, but got ${compiler.warnings}');
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[0].message.kind);
+  Expect.equals("T", compiler.warnings[0].node.toString());
+}
+
+test2() {
+  var compiler = compile(r"""
+class B<T extends S, S extends T> {}
+
+void main() {
+  new B();
+}
+""");
+
+  Expect.isFalse(compiler.compilationFailed);
+  print(compiler.errors);
+  Expect.isTrue(compiler.errors.isEmpty, 'unexpected errors');
+  Expect.equals(2, compiler.warnings.length,
+                'expected exactly one error, but got ${compiler.warnings}');
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[0].message.kind);
+  Expect.equals("T", compiler.warnings[0].node.toString());
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[1].message.kind);
+  Expect.equals("S", compiler.warnings[1].node.toString());
+}
+
+test3() {
+  var compiler = compile(r"""
+class C<T extends S, S extends U, U extends T> {}
+
+void main() {
+  new C();
+}
+""");
+
+  Expect.isFalse(compiler.compilationFailed);
+  print(compiler.errors);
+  Expect.isTrue(compiler.errors.isEmpty, 'unexpected errors');
+  Expect.equals(3, compiler.warnings.length,
+                'expected exactly one error, but got ${compiler.warnings}');
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[0].message.kind);
+  Expect.equals("T", compiler.warnings[0].node.toString());
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[1].message.kind);
+  Expect.equals("S", compiler.warnings[1].node.toString());
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[2].message.kind);
+  Expect.equals("U", compiler.warnings[2].node.toString());
+}
+
+test4() {
+  var compiler = compile(r"""
+class D<T extends S, S extends U, U extends S> {}
+
+void main() {
+  new D();
+}
+""");
+
+  Expect.isFalse(compiler.compilationFailed);
+  print(compiler.errors);
+  Expect.isTrue(compiler.errors.isEmpty, 'unexpected errors');
+  Expect.equals(2, compiler.warnings.length,
+                'expected exactly one error, but got ${compiler.warnings}');
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[0].message.kind);
+  Expect.equals("S", compiler.warnings[0].node.toString());
+
+  Expect.equals(MessageKind.CYCLIC_TYPE_VARIABLE,
+                compiler.warnings[1].message.kind);
+  Expect.equals("U", compiler.warnings[1].node.toString());
+}
+
+main() {
+  test1();
+  test2();
+  test3();
+  test4();
+}