Refactoring resolution of local access and unqualified access of statics

pkg/compiler/lib/src/enqueue.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.
 
 part of dart2js;
 
 typedef ItemCompilationContext ItemCompilationContextCreator();
 
 class EnqueueTask extends CompilerTask {
   final ResolutionEnqueuer resolution;
@@ skipping 528 matching lines @@
     }
   }
 
   /**
    * Documentation wanted -- johnniwinther
    *
    * Invariant: [element] must be a declaration element.
    */
   void registerStaticUse(Element element) {
     if (element == null) return;
-    assert(invariant(element, element.isDeclaration));
+    assert(invariant(element, element.isDeclaration,
+        message: "Element ${element} is not the declaration."));
     if (Elements.isStaticOrTopLevel(element) && element.isField) {
       universe.registerStaticFieldUse(element);
     }
     addToWorkList(element);
     compiler.backend.registerStaticUse(element, this);
   }
 
   void registerGetOfStaticFunction(FunctionElement element) {
     registerStaticUse(element);
     compiler.backend.registerGetOfStaticFunction(this);
@@ skipping 383 matching lines @@
   void processWorkItem(void f(WorkItem work), WorkItem work) {
     f(work);
   }
 }
 
 void removeFromSet(Map<String, Set<Element>> map, Element element) {
   Set<Element> set = map[element.name];
   if (set == null) return;
   set.remove(element);
 }