Version 0.8.10.1

dart/sdk/lib/async/future_impl.dart

 // Copyright (c) 2012, 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 dart.async;
 
 /** The onValue and onError handlers return either a value or a future */
 typedef dynamic _FutureOnValue<T>(T value);
 /** Test used by [Future.catchError] to handle skip some errors. */
 typedef bool _FutureErrorTest(var error);
@@ skipping 496 matching lines @@
           }
           listenerHasValue = false;
         }
       });
       if (isPropagationAborted) return;
       // If the listener's value is a future we need to chain it.
       if (listenerHasValue && listenerValueOrError is Future) {
         Future chainSource = listenerValueOrError;
         // Shortcut if the chain-source is already completed. Just continue the
         // loop.
-        if (chainSource is _Future && (chainSource as _Future)._isComplete) {
+        if (chainSource is _Future && chainSource._isComplete) {
           // propagate the value (simulating a tail call).
           listener._isChained = true;
           source = chainSource;
           listeners = listener;
           continue;
         }
         _chainFutures(chainSource, listener);
         return;
       }
 
       if (listenerHasValue) {
         listeners = listener._removeListeners();
         listener._setValue(listenerValueOrError);
       } else {
         listeners = listener._removeListeners();
         _AsyncError asyncError = listenerValueOrError;
         listener._setError(asyncError.error, asyncError.stackTrace);
       }
       // Prepare for next round.
       source = listener;
     }
   }
 }