Ensure that element handles never refer to Member objects.

pkg/analyzer/test/src/summary/resynthesize_test.dart

 // Copyright (c) 2015, 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 test.src.serialization.elements_test;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 770 matching lines @@
       }
       expect(resynthesized.typeFormals.length, original.typeFormals.length,
           reason: desc);
       for (int i = 0; i < resynthesized.typeFormals.length; i++) {
         compareTypeParameterElements(resynthesized.typeFormals[i],
             original.typeFormals[i], '$desc bound type parameter $i');
       }
     } else if (resynthesized is VoidTypeImpl && original is VoidTypeImpl) {
       expect(resynthesized, same(original));
     } else if (resynthesized.runtimeType != original.runtimeType) {
-      fail(
-          'Type mismatch: expected ${original.runtimeType}, got ${resynthesized.runtimeType}');
+      fail('Type mismatch: expected ${original.runtimeType},'
+          ' got ${resynthesized.runtimeType} ($desc)');
     } else {
       fail('Unimplemented comparison for ${original.runtimeType}');
     }
   }
 
   void compareUriReferencedElements(UriReferencedElementImpl resynthesized,
       UriReferencedElementImpl original, String desc) {
     compareElements(resynthesized, original, desc);
     expect(resynthesized.uri, original.uri);
     expect(resynthesized.uriOffset, original.uriOffset, reason: desc);
     expect(resynthesized.uriEnd, original.uriEnd, reason: desc);
   }
 
   void compareVariableElements(
       VariableElement resynthesized, VariableElement original, String desc) {
     compareElements(resynthesized, original, desc);
     compareTypes(resynthesized.type, original.type, desc);
     VariableElementImpl originalActual = getActualElement(original, desc);
     if (originalActual is ConstVariableElement) {
       VariableElementImpl resynthesizedActual =
           getActualElement(resynthesized, desc);
       Expression initializer = resynthesizedActual.constantInitializer;
       if (constantInitializersAreInvalid) {
         _assertUnresolvedIdentifier(initializer, desc);
       } else {
-        compareConstAsts(initializer, originalActual.constantInitializer, desc);
+        compareConstAsts(initializer, originalActual.constantInitializer,
+            '$desc initializer');
       }
     }
     checkPossibleMember(resynthesized, original, desc);
   }
 
   /**
    * Serialize the given [library] into a summary.  Then create a
    * [_TestSummaryResynthesizer] which can deserialize it, along with any
    * references it makes to `dart:core`.
    *
@@ skipping 54 matching lines @@
   }
 
   fail_library_hasExtUri() {
     checkLibrary('import "dart-ext:doesNotExist.dart";');
   }
 
   ElementImpl getActualElement(Element element, String desc) {
     if (element is ElementImpl) {
       return element;
     } else if (element is ElementHandle) {
-      return getActualElement(element.actualElement, desc);
+      Element actualElement = element.actualElement;
+      // A handle should never point to a member, because if it did, then
+      // "is Member" checks on the handle would produce the wrong result.
+      expect(actualElement, isNot(new isInstanceOf<Member>()), reason: desc);
+      return getActualElement(actualElement, desc);
     } else if (element is Member) {
       return getActualElement(element.baseElement, desc);
     } else {
       fail('Unexpected type for resynthesized ($desc):'
           ' ${element.runtimeType}');
       return null;
     }
   }
 
   /**
@@ skipping 2367 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }