Add EnumSet.

pkg/compiler/lib/src/resolution/registry.dart

 // Copyright (c) 2014, 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.resolution.registry;
 
 import '../common.dart';
 import '../common/backend_api.dart' show
     Backend,
     ForeignResolver;
@@ skipping 18 matching lines @@
 import '../universe/call_structure.dart' show
     CallStructure;
 import '../universe/selector.dart' show
     Selector;
 import '../universe/use.dart' show
     DynamicUse,
     StaticUse,
     TypeUse;
 import '../universe/world_impact.dart' show
     WorldImpactBuilder;
-import '../world.dart' show World;
+import '../util/enumset.dart' show
+    EnumSet;
+import '../world.dart' show
+    World;
 
 import 'send_structure.dart';
 
 import 'members.dart' show
     ResolverVisitor;
 import 'tree_elements.dart' show
     TreeElementMapping;
 
 class _ResolutionWorldImpact extends ResolutionImpact with WorldImpactBuilder {
   final String name;
-  Setlet<Feature> _features;
+  EnumSet<Feature> _features;
   Setlet<MapLiteralUse> _mapLiterals;
   Setlet<ListLiteralUse> _listLiterals;
   Setlet<String> _constSymbolNames;
   Setlet<ConstantExpression> _constantLiterals;
 
   _ResolutionWorldImpact(this.name);
 
   void registerMapLiteral(MapLiteralUse mapLiteralUse) {
     assert(mapLiteralUse != null);
     if (_mapLiterals == null) {
@@ skipping 30 matching lines @@
   }
 
   @override
   Iterable<String> get constSymbolNames {
     return _constSymbolNames != null
         ? _constSymbolNames : const <String>[];
   }
 
   void registerFeature(Feature feature) {
     if (_features == null) {
-      _features = new Setlet<Feature>();
+      _features = new EnumSet<Feature>();
     }
     _features.add(feature);
   }
 
   @override
   Iterable<Feature> get features {
-    return _features != null ? _features : const <Feature>[];
+    return _features != null
+        ? _features.iterable(Feature.values) : const <Feature>[];
   }
 
   void registerConstantLiteral(ConstantExpression constant) {
     if (_constantLiterals == null) {
       _constantLiterals = new Setlet<ConstantExpression>();
     }
     _constantLiterals.add(constant);
   }
 
   Iterable<ConstantExpression> get constantLiterals {
@@ skipping 294 matching lines @@
   @override
   void registerInstantiatedType(InterfaceType type) {
     registry.registerInstantiation(type);
   }
 
   @override
   DartType resolveTypeFromString(Node node, String typeName) {
     return visitor.resolveTypeFromString(node, typeName);
   }
 }