Use Entity instead of Element in ConstantValue

pkg/compiler/lib/src/ssa/optimize.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.
 
 import '../common/codegen.dart' show CodegenRegistry, CodegenWorkItem;
 import '../common/names.dart' show Selectors;
 import '../common/tasks.dart' show CompilerTask;
 import '../compiler.dart' show Compiler;
 import '../constants/constant_system.dart';
 import '../constants/values.dart';
 import '../core_types.dart' show CommonElements;
 import '../dart_types.dart';
 import '../elements/elements.dart';
+import '../elements/entities.dart';
 import '../js/js.dart' as js;
 import '../js_backend/backend_helpers.dart' show BackendHelpers;
 import '../js_backend/js_backend.dart';
 import '../native/native.dart' as native;
 import '../tree/dartstring.dart' as ast;
 import '../types/types.dart';
 import '../universe/selector.dart' show Selector;
 import '../universe/side_effects.dart' show SideEffects;
 import '../util/util.dart';
 import '../world.dart' show ClosedWorld;
@@ skipping 860 matching lines @@
         }
       }
     }
 
     // HFieldGet of a constructed constant can be replaced with the constant's
     // field.
     if (receiver is HConstant) {
       ConstantValue constant = receiver.constant;
       if (constant.isConstructedObject) {
         ConstructedConstantValue constructedConstant = constant;
-        Map<Element, ConstantValue> fields = constructedConstant.fields;
+        Map<FieldEntity, ConstantValue> fields = constructedConstant.fields;
         ConstantValue value = fields[node.element];
         if (value != null) {
           return graph.addConstant(value, closedWorld);
         }
       }
     }
 
     return node;
   }
 
@@ skipping 1837 matching lines @@
 
     keyedValues.forEach((receiver, values) {
       result.keyedValues[receiver] =
           new Map<HInstruction, HInstruction>.from(values);
     });
 
     result.nonEscapingReceivers.addAll(nonEscapingReceivers);
     return result;
   }
 }