Implement redirecting constructors.

dart/tests/language/redirecting_factory_infinite_steps_test.dart

Index: dart/tests/language/redirecting_factory_infinite_steps_test.dart
diff --git a/dart/tests/language/redirecting_factory_infinite_steps_test.dart b/dart/tests/language/redirecting_factory_infinite_steps_test.dart
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index 0000000000000000000000000000000000000000..e6550801e57f55984c16f6c472d369a8890933a5
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+++ b/dart/tests/language/redirecting_factory_infinite_steps_test.dart
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+// 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.
+
+// From Dart Language Specification, 0.12 M1, "7.6.2 Factories": It is
+// a compile-time error if a redirecting factory constructor does not
+// redirect to a non-redirecting factory constructor or to a
+// generative constructor in a finite number of steps.
+
+// TODO(ahe): The above specification will probably change to
+// something like: "It is a compile-time error if a redirecting
+// factory constructor redirects to itself, either directly or
+// indirectly via a sequence of redirections."
+
+class Foo extends Bar {
+  factory Foo() = Bar; /// 01: static type warning, dynamic type error
+}
+
+class Bar {
+  factory Bar() = Foo; /// 02: compile-time error
+}
+
+main() {
+  new Foo();
+}