Do not emit substitutions for unnamed mixin applications.

sdk/lib/_internal/compiler/implementation/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 'dart:collection' show LinkedHashMap;
 
 import 'elements.dart';
 import '../../compiler.dart' as api;
@@ skipping 1507 matching lines @@
         super(name, ElementKind.CLASS, enclosing);
 
   int get hashCode => id;
   ClassElement get patch => super.patch;
   ClassElement get origin => super.origin;
   ClassElement get declaration => super.declaration;
   ClassElement get implementation => super.implementation;
 
   bool get hasBackendMembers => !backendMembers.isEmpty;
 
+  bool get isUnnamedMixinApplication => false;
+
   InterfaceType computeType(Compiler compiler) {
     if (thisType == null) {
       if (origin == null) {
         Link<DartType> parameters = computeTypeParameters(compiler);
         thisType = new InterfaceType(this, parameters);
         if (parameters.isEmpty) {
           rawTypeCache = thisType;
         } else {
           var dynamicParameters = const Link<DartType>();
           parameters.forEach((_) {
@@ skipping 442 matching lines @@
 
   Link<FunctionElement> constructors = new Link<FunctionElement>();
 
   ClassElement mixin;
 
   MixinApplicationElementX(SourceString name, Element enclosing, int id,
                            this.node, this.modifiers)
       : super(name, enclosing, id, STATE_NOT_STARTED);
 
   bool get isMixinApplication => true;
+  bool get isUnnamedMixinApplication => node is! NamedMixinApplication;
   bool get hasConstructor => !constructors.isEmpty;
   bool get hasLocalScopeMembers => !constructors.isEmpty;
 
   unsupported(message) {
     throw new UnsupportedError('$message is not supported on $this');
   }
 
   get patch => null;
   get origin => null;
 
@@ skipping 179 matching lines @@
 
   MetadataAnnotation ensureResolved(Compiler compiler) {
     if (resolutionState == STATE_NOT_STARTED) {
       compiler.resolver.resolveMetadataAnnotation(this);
     }
     return this;
   }
 
   String toString() => 'MetadataAnnotation($value, $resolutionState)';
 }