Patch refactoring.

lib/compiler/implementation/compile_time_constants.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.
 
 /**
  * The [ConstantHandler] keeps track of compile-time constants,
  * initializations of global and static fields, and default values of
  * optional parameters.
  */
 class ConstantHandler extends CompilerTask {
@@ skipping 781 matching lines @@
    */
   void evaluateConstructorFieldValues(List<Constant> arguments) {
     compiler.withCurrentElement(constructor, () {
       assignArgumentsToParameters(arguments);
       evaluateConstructorInitializers();
     });
   }
 
   List<Constant> buildJsNewArguments(ClassElement classElement) {
     List<Constant> jsNewArguments = <Constant>[];
-    classElement.forEachInstanceField(
+    classElement.implementation.forEachInstanceField(
         includeBackendMembers: true,
         includeSuperMembers: true,
         f: (ClassElement enclosing, Element field) {
       Constant fieldValue = fieldValues[field];
       if (fieldValue === null) {
         // Use the default value.
         fieldValue = compiler.compileConstant(field);
       }
       jsNewArguments.add(fieldValue);
     });
     return jsNewArguments;
   }
 }