Split World usage into open, inference, and closed world.

pkg/compiler/lib/src/js_emitter/interceptor_stub_generator.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.
 
 part of dart2js.js_emitter;
 
 class InterceptorStubGenerator {
   final Compiler compiler;
   final Namer namer;
   final JavaScriptBackend backend;
@@ skipping 230 matching lines @@
       //        if (a0 >>> 0 === a0 && a0 < receiver.length) {
       //          return receiver[a0] = a1;
       //        }
       //      }
       //    }
       bool containsArray = classes.contains(helpers.jsArrayClass);
       bool containsString = classes.contains(helpers.jsStringClass);
       bool containsJsIndexable =
           helpers.jsIndexingBehaviorInterface.isResolved &&
               classes.any((cls) {
-                return compiler.world
+                return compiler.closedWorld
                     .isSubtypeOf(cls, helpers.jsIndexingBehaviorInterface);
               });
       // The index set operator requires a check on its set value in
       // checked mode, so we don't optimize the interceptor if the
       // compiler has type assertions enabled.
       if (selector.isIndexSet &&
           (compiler.options.enableTypeAssertions || !containsArray)) {
         return null;
       }
       if (!containsArray && !containsString) {
@@ skipping 128 matching lines @@
 
           var map = new jsAst.ObjectInitializer(properties);
           elements.add(map);
         }
       }
     }
 
     return new jsAst.ArrayInitializer(elements);
   }
 }