Tests for `void`.

pkg/compiler/lib/src/js_backend/backend_impact.dart

 // Copyright (c) 2015, 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.js_helpers.impact;
 
 import '../common/names.dart';
 import '../compiler.dart' show Compiler;
 import '../core_types.dart' show CommonElements;
 import '../elements/resolution_types.dart' show ResolutionInterfaceType;
@@ skipping 595 matching lines @@
 
   BackendImpact get mapLiteralClass {
     return _mapLiteralClass ??= new BackendImpact(globalUses: [
       helpers.mapLiteralConstructor,
       helpers.mapLiteralConstructorEmpty,
       helpers.mapLiteralUntypedMaker,
       helpers.mapLiteralUntypedEmptyMaker
     ]);
   }
 
+  BackendImpact _objectClass;
+
+  // TODO(floitsch): this should probably be a `void` impact, and not on
+  // `Object`.
+  BackendImpact get objectClass {
+    return _objectClass ??=
+        new BackendImpact(globalClasses: [helpers.voidClass]);
+  }
+
   BackendImpact _closureClass;
 
   BackendImpact get closureClass {
     return _closureClass ??=
         new BackendImpact(globalUses: [helpers.closureFromTearOff]);
   }
 
   BackendImpact _listClasses;
 
   BackendImpact get listClasses {
@@ skipping 102 matching lines @@
 
   BackendImpact _staticClosure;
 
   /// Backend impact for performing closurization of a top-level or static
   /// function.
   BackendImpact get staticClosure {
     return _staticClosure ??=
         new BackendImpact(globalClasses: [helpers.closureClass]);
   }
 }