Use entities in Selector methods

pkg/compiler/lib/src/world.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 dart2js.world;
 
 import 'closure.dart' show ClosureClassElement, SynthesizedCallMethodElementX;
 import 'common/backend_api.dart' show BackendClasses;
 import 'common.dart';
 import 'constants/constant_system.dart';
@@ skipping 912 matching lines @@
   @override
   bool hasElementIn(ClassElement cls, Selector selector, Element element) {
     // Use [:implementation:] of [element]
     // because our function set only stores declarations.
     Element result = findMatchIn(cls, selector);
     return result == null
         ? false
         : result.implementation == element.implementation;
   }
 
-  Element findMatchIn(ClassElement cls, Selector selector,
+  MemberElement findMatchIn(ClassElement cls, Selector selector,
       {ClassElement stopAtSuperclass}) {
     // Use the [:implementation] of [cls] in case the found [element]
     // is in the patch class.
-    var result = cls.implementation
+    return cls.implementation
         .lookupByName(selector.memberName, stopAt: stopAtSuperclass);
-    return result;
   }
 
   /// Returns whether a [selector] call on an instance of [cls]
   /// will hit a method at runtime, and not go through [noSuchMethod].
   bool hasConcreteMatch(ClassElement cls, Selector selector,
       {ClassElement stopAtSuperclass}) {
     assert(invariant(cls, isInstantiated(cls),
         message: '$cls has not been instantiated.'));
-    Element element = findMatchIn(cls, selector);
+    MemberElement element = findMatchIn(cls, selector);
     if (element == null) return false;
 
     if (element.isAbstract) {
       ClassElement enclosingClass = element.enclosingClass;
       return hasConcreteMatch(enclosingClass.superclass, selector);
     }
     return selector.appliesUntyped(element);
   }
 
   @override
@@ skipping 233 matching lines @@
       return getMightBePassedToApply(element.expression);
     }
     return functionsThatMightBePassedToApply.contains(element);
   }
 
   @override
   bool getCurrentlyKnownMightBePassedToApply(Element element) {
     return getMightBePassedToApply(element);
   }
 }