Native abstract classes may be 'instantiated'

sdk/lib/_internal/compiler/implementation/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;
 
 class EnqueueTask extends CompilerTask {
   final ResolutionEnqueuer resolution;
   final CodegenEnqueuer codegen;
 
@@ skipping 99 matching lines @@
    * Adds [element] to the work list if it has not already been processed.
    */
   void internalAddToWorkList(Element element);
 
   void registerInstantiatedType(InterfaceType type, TreeElements elements) {
     task.measure(() {
       ClassElement cls = type.element;
       elements.registerDependency(cls);
       cls.ensureResolved(compiler);
       universe.instantiatedTypes.add(type);
-      if (!cls.isAbstract(compiler)) {
+      if (!cls.isAbstract(compiler)
+          // We can't use the closed-world assumption with native abstract
+          // classes; a native abstract class may have non-abstract subclasses
+          // not declared to the program.  Instances of these classes are
+          // indistinguishable from the abstract class.
+          || cls.isNative()) {

[ngeoffray, 2013/09/10 11:55:37]

Could we avoid marking the native classes abstract instead?

         universe.instantiatedClasses.add(cls);
       }
       onRegisterInstantiatedClass(cls);
     });
   }
 
   void registerInstantiatedClass(ClassElement cls, TreeElements elements) {
     cls.ensureResolved(compiler);
     registerInstantiatedType(cls.rawType, elements);
   }
@@ skipping 594 matching lines @@
     while(!queue.isEmpty) {
       // TODO(johnniwinther): Find an optimal process order for codegen.
       f(queue.removeLast());
     }
   }
 
   void _logSpecificSummary(log(message)) {
     log('Compiled ${generatedCode.length} methods.');
   }
 }