Make isEmpty a getter.

lib/coreimpl/queue.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.
 
 
 /**
  * An entry in a doubly linked list. It contains a pointer to the next
  * entry, the previous entry, and the boxed element.
  */
 class DoubleLinkedQueueEntry<E> {
@@ skipping 140 matching lines @@
   DoubleLinkedQueueEntry<E> firstEntry() {
     return _sentinel.nextEntry();
   }
 
   int get length {
     int counter = 0;
     forEach(void _(E element) { counter++; });
     return counter;
   }
 
-  bool isEmpty() {
+  bool get isEmpty {
     return (_sentinel._next === _sentinel);
   }
 
   void clear() {
     _sentinel._next = _sentinel;
     _sentinel._previous = _sentinel;
   }
 
   void forEach(void f(E element)) {
     DoubleLinkedQueueEntry<E> entry = _sentinel._next;
@@ skipping 82 matching lines @@
   }
 
   E next() {
     if (!hasNext) {
       throw const NoMoreElementsException();
     }
     _currentEntry = _currentEntry._next;
     return _currentEntry.element;
   }
 }