Use MemberEntity more in type_graph_nodes

pkg/compiler/lib/src/inferrer/inferrer_engine.dart

 // Copyright (c) 2017, 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 'package:kernel/ast.dart' as ir;
 
 import '../common.dart';
 import '../common/names.dart';
 import '../compiler.dart';
 import '../constants/expressions.dart';
@@ skipping 1026 matching lines @@
     types.allocatedClosures.forEach(cleanup);
     types.allocatedClosures.clear();
 
     analyzedElements.clear();
     generativeConstructorsExposingThis.clear();
 
     types.allocatedMaps.values.forEach(cleanup);
     types.allocatedLists.values.forEach(cleanup);
   }
 
-  Iterable<Element> getCallersOf(MemberElement element) {
+  Iterable<MemberEntity> getCallersOf(MemberElement element) {
     if (compiler.disableTypeInference) {
       throw new UnsupportedError(
           "Cannot query the type inferrer when type inference is disabled.");
     }
     MemberTypeInformation info = types.getInferredTypeOfMember(element);
     return info.callers;
   }
 
   /**
    * Returns the type of [element] when being called with [selector].
@@ skipping 38 matching lines @@
   /**
    * Records that the captured variable [local] is read.
    */
   void recordCapturedLocalRead(Local local) {}
 
   /**
    * Records that the variable [local] is being updated.
    */
   void recordLocalUpdate(Local local, TypeInformation type) {}
 }