Check that interface constructors and default class constructors are compatible.

corelib/src/implementation/promise_implementation.dart

 // 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.
 
 // Dart core library.
 
 class PromiseImpl<T> implements Promise<T> {
 
   // Enumeration of possible states:
   static final int CREATED = 0;
@@ skipping 27 matching lines @@
   Queue<Function> _cancelListeners;
 
   PromiseImpl()
       : _state = CREATED,
         _value = null,
         _error = null,
         _normalListeners = null,
         _errorListeners = null,
         _cancelListeners = null {}
 
-  PromiseImpl.fromValue(val)
+  PromiseImpl.fromValue(T val)
       : _state = COMPLETE_NORMAL,
         _value = val,
         _error = null,
         _normalListeners = null,
         _errorListeners = null,
         _cancelListeners = null {}
 
   // Properties and methods from Promise:
 
   T get value() {
@@ skipping 311 matching lines @@
         } 
       }
       return process(marshalled);
     }).flatten();
   }
 
   Promise<SendPort> _promise;
   static Map<SendPort, Dispatcher> _dispatchers;
 
 }