Use Entity instead of Element in ConstantValue

pkg/compiler/lib/src/serialization/equivalence.dart

 // Copyright (c) 2016, 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.
 
 /// Functions for asserting equivalence across serialization.
 
 library dart2js.serialization.equivalence;
 
 import '../closure.dart';
 import '../common/resolution.dart';
@@ skipping 856 matching lines @@
             value1.fields,
             value2.fields,
             areElementsEquivalent,
             (a, b) => strategy.testConstantValues(
                 value1, value2, 'fields.values', a, b));
   }
 
   @override
   bool visitFunction(
       FunctionConstantValue value1, FunctionConstantValue value2) {
-    return strategy.testElements(
-        value1, value2, 'element', value1.element, value2.element);
+    MethodElement method1 = value1.element;
+    MethodElement method2 = value2.element;
+    return strategy.testElements(value1, value2, 'element', method1, method2);
   }
 
   @override
   bool visitList(ListConstantValue value1, ListConstantValue value2) {
     return strategy.testTypes(
             value1, value2, 'type', value1.type, value2.type) &&
         strategy.testConstantValueLists(
             value1, value2, 'entries', value1.entries, value2.entries);
   }
 
@@ skipping 1139 matching lines @@
 }
 
 bool areMetadataAnnotationsEquivalent(
     MetadataAnnotation metadata1, MetadataAnnotation metadata2) {
   if (metadata1 == metadata2) return true;
   if (metadata1 == null || metadata2 == null) return false;
   return areElementsEquivalent(
           metadata1.annotatedElement, metadata2.annotatedElement) &&
       areConstantsEquivalent(metadata1.constant, metadata2.constant);
 }