Introduce WorldImpact

pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.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 dart2js.ir_builder_task;
 
 import '../closure.dart' as closurelib;
 import '../closure.dart' hide ClosureScope;
 import '../constants/expressions.dart';
 import '../dart_types.dart';
@@ skipping 83 matching lines @@
       Set<Element> resolved = compiler.enqueuer.resolution.resolvedElements;
       resolved.forEach(buildNode);
     });
   }
 
   bool canBuild(Element element) {
     // If using JavaScript backend, don't try to bail out early.
     if (compiler.backend is JavaScriptBackend) return true;
 
     if (element is TypedefElement) return false;
+    if (element is ClassElement) return false;
     if (element is FunctionElement) {
       // TODO(sigurdm): Support native functions for dart2js.
       assert(invariant(element, !element.isNative));
 
       if (element is ConstructorElement) {
         if (!element.isGenerativeConstructor) {
           // TODO(kmillikin,sigurdm): Support constructors.
           return false;
         }
         if (element.isSynthesized) {
@@ skipping 3004 matching lines @@
     node.body = replacementFor(node.body);
   }
 }
 
 /// Visit a just-deleted subterm and unlink all [Reference]s in it.
 class RemovalVisitor extends ir.RecursiveVisitor {
   processReference(ir.Reference reference) {
     reference.unlink();
   }
 }