Fix crash in dartc when given cyclic type variable bounds.

compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java

Index: compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java b/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
index 0a8c9f619455213cbac5da2c80ea1c05a331f6f0..d77d8938b0d28e57f164ec357b0631cc63ccddd2 100644
--- a/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
+++ b/compiler/java/com/google/dart/compiler/resolver/TypeErrorCode.java
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 package com.google.dart.compiler.resolver;
@@ -16,6 +16,8 @@ public enum TypeErrorCode implements ErrorCode {
   CANNOT_BE_RESOLVED("cannot resolve %s"),
   CANNOT_OVERRIDE_TYPED_MEMBER("cannot override %s of %s because %s is not assignable to %s"),
   CANNOT_OVERRIDE_METHOD_NOT_SUBTYPE("cannot override %s of %s because %s is not a subtype of %s"),
+  CYCLIC_REFERENCE_TO_TYPE_VARIABLE(
+      "Invalid type expression, cyclic reference to type variable '%s'"),
   DEFAULT_CONSTRUCTOR_TYPES(
       "Constructor '%s' in '%s' has parameters types (%s), doesn't match '%s' in '%s' with (%s)"),
   EXTRA_ARGUMENT("extra argument"),