Make .enclosingClass always return the declaration

pkg/compiler/lib/src/elements/modelx.dart

 // Copyright (c) 2013, 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 elements.modelx;
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
 import '../common/resolution.dart' show Resolution, ParsingContext;
 import '../compiler.dart' show Compiler;
@@ skipping 145 matching lines @@
   LibraryElement get implementationLibrary {
     Element element = this;
     while (!identical(element.kind, ElementKind.LIBRARY)) {
       element = element.enclosingElement;
     }
     return element;
   }
 
   ClassElement get enclosingClass {
     for (Element e = this; e != null; e = e.enclosingElement) {
-      if (e.isClass) return e;
+      if (e.isClass) return e.declaration;
     }
     return null;
   }
 
   /**
    * Creates the scope for this element.
    */
   Scope buildScope() => enclosingElement.buildScope();
 
   String toString() {
@@ skipping 2173 matching lines @@
         message: 'Malformedness has not yet been computed for $this.'));
     return _isEffectiveTargetMalformed == true;
   }
 
   accept(ElementVisitor visitor, arg) {
     return visitor.visitConstructorElement(this, arg);
   }
 
   ConstructorElement get definingConstructor => null;
 
-  ClassElement get enclosingClass => enclosingElement;
+  ClassElement get enclosingClass => enclosingElement.declaration;
 }
 
 class DeferredLoaderGetterElementX extends GetterElementX
     implements GetterElement {
   final PrefixElement prefix;
 
   DeferredLoaderGetterElementX(PrefixElement prefix)
       : this.prefix = prefix,
         super(Identifiers.loadLibrary, Modifiers.EMPTY, prefix, false) {
     functionSignature =
@@ skipping 1050 matching lines @@
       body = node.asFunctionExpression().body;
     }
     return new ParsedResolvedAst(
         declaration,
         node,
         body,
         definingElement.treeElements,
         definingElement.compilationUnit.script.resourceUri);
   }
 }