Check for cyclic reference in typedefs

tests/language/cyclic_typedef_test.dart

+// 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.
+
+// Check that cyclic reference of a typedef is a compile-time error.
+
+// To test various cyclic references the definition of the [:typedef A():] is
+// split over several lines:
+typedef
+
+// Cyclic through return type.
+A /// 01: compile-time error
+
+A // The name of the typedef
+
+( // The left parenthesis of the typedef arguments.
+
+// Cyclic through parameter type.
+A a /// 02: compile-time error
+
+// Cyclic through optional parameter type.
+[A a] /// 03: compile-time error
+
+// Cyclic through named parameter type.
+{A a} /// 04: compile-time error
+
+// Cyclic through generic parameter type.
+List<A> a /// 05: compile-time error
+
+// Cyclic through return type of function typed parameter.
+A f() /// 06: compile-time error
+
+// Cyclic through parameter type of function typed parameter.
+f(A a) /// 07: compile-time error
+
+// Cyclic through another typedef.
+B b /// 08: compile-time error
+
+// Cyclic through another more typedefs.
+C c /// 09: compile-time error
+
+); // The right parenthesis of the typedef arguments.
+
+typedef B(A a);
+typedef C(B b);
+
+void testA(A a) {}
+
+void main() {
+  testA(null);
+}