Implement cycle-checking and code generation for redirecting constructors.

frog/tests/leg_only/src/CyclicConstructorTest.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file

[ngeoffray, 2012/02/16 11:23:50]

2011 -> 2012.

Also, this should probably be a language test.

[karlklose, 2012/02/17 13:35:00]

Done.
Left it in leg_only for now, but we should go through all the leg_only tests to
decide which of them can be promoted to language tests.

+// 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.
+
+class A {
+  A();
+  A.a() : this.b();
+  A.b() : this.a();
+  A.c() : this.b();
+}
+
+main() {
+  new A();
+  new A.a();  /// 01: compile-time error
+  new A.b();  /// 02: compile-time error
+  new A.c();  /// 03: compile-time error

[ngeoffray, 2012/02/16 11:23:50]

As discussed yesterday about the multi-tests, will that work on dartc? class A
will be analyzed even if the constructors are not invoked.

[ahe, 2012/02/16 11:35:40]

Use this trick:

 A.a()
: this.b() /// 01: compile-time error
;

[karlklose, 2012/02/17 13:35:00]

Done.

+}