Function type checking

compiler/lib/implementation/core.js

 // Copyright (c) 2011, 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.
 
 /**
  * Helpers for lazy static initialization.
  */
 var static$uninitialized = {};
 var static$initializing = {};
 
@@ skipping 138 matching lines @@
     child.prototype.constructor = child;
   }
 }
 
 /**
  * @param {Function} fn
  * @param {Object|undefined} thisObj
  * @param {...*} var_args
  */
 function $bind(fn, thisObj, var_args) {
+  var func;
   if (arguments.length > 2) {
     var boundArgs = Array.prototype.slice.call(arguments, 2);
-    return function() {
+    func = function() {
       // Prepend the bound arguments to the current arguments.
       var newArgs = Array.prototype.slice.call(arguments);
       Array.prototype.unshift.apply(newArgs, boundArgs);
       return fn.apply(thisObj, newArgs);
     };
   } else {
-    return function() {
+    func = function() {
       return fn.apply(thisObj, arguments);
     };
   }
+  if(fn.$lookupRTT) {
+    func.$lookupRTT = function() {
+      return fn.$lookupRTT.apply(thisObj, arguments);
+    };
+  }
+  return func;
 }
 
 /**
  * Dart null object that should be used by JS implementation to test for
  * Dart null.
  *
  * TODO(ngeoffray): update dartc to generate this variable instead of
  *                  undefined.
  * @const
  */
@@ skipping 281 matching lines @@
     return match;
   }
   o.$dartConstId = id;
   $consts[key] = o;
   return o;
 }
 
 function $Dart$MapLiteralFactory() {
   return native__CoreJsUtil__newMapLiteral();
 }