Fixes #178

lib/runtime/dart_runtime.js

 // 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.
 
 var dart, _js_helper, _js_primitives;
 (function (dart) {
   'use strict';
 
   let defineProperty = Object.defineProperty;
   let getOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;
@@ skipping 867 matching lines @@
       objectKey.push(name);
       objectKey.push(obj[name]);
     }
     return multiKeyPutIfAbsent(constants, objectKey, () => obj);
   }
   dart.const = constant;
 
   /** Sets the type of `obj` to be `type` */
   function setType(obj, type) {
     obj.__proto__ = type.prototype;
+    return obj;
   }
   dart.setType = setType;
 
   /** Sets the internal runtime type of `obj` to be `type` */
   function setRuntimeType(obj, type) {
     obj[_runtimeType] = type;
   }
   dart.setRuntimeType = setRuntimeType;
 
   // The following are helpers for Object methods when the receiver
@@ skipping 86 matching lines @@
   dart.defineLibrary = defineLibrary;
 
   // TODO(jmesserly): hack to bootstrap the SDK
   _js_helper = _js_helper || {};
   _js_helper.checkNum = notNull;
 
   _js_primitives = _js_primitives || {};
   _js_primitives.printString = (s) => console.log(s);
 
 })(dart || (dart = {}));