Fix issue 6472 that exhibited a few crashing bugs in dart2js.

lib/compiler/implementation/universe/universe.dart

 // 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.
 
 library universe;
 
 import '../closure.dart';
 import '../elements/elements.dart';
 import '../dart2jslib.dart';
 import '../runtime_types.dart';
@@ skipping 412 matching lines @@
     }
 
     ClassElement self = receiverType.element;
 
     if (other.implementsInterface(self)
         || other.isSubclassOf(self)
         || compiler.world.hasAnySubclassThatImplements(other, receiverType)) {
       return appliesUntyped(element, compiler);
     }
 
-    if (!self.isInterface() && self.isSubclassOf(other)) {
+    if (!self.isTypedef() && !self.isInterface() && self.isSubclassOf(other)) {
       // Resolve an invocation of [element.name] on [self]. If it
       // is found, this selector is a candidate.
       return hasElementIn(self, element) && appliesUntyped(element, compiler);
     }
 
     return false;
   }
 }