Make hasNext a getter instead of a method.

lib/compiler/implementation/util/link_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.
 
 class LinkIterator<T> implements Iterator<T> {
   Link<T> current;
   LinkIterator(Link<T> this.current);
-  bool hasNext() => !current.isEmpty();
+  bool get hasNext => !current.isEmpty();
   T next() {
     T result = current.head;
     current = current.tail;
     return result;
   }
 }
 
 class LinkEntry<T> extends Link<T> {
   final T head;
   Link<T> tail;
@@ skipping 90 matching lines @@
     length++;
     LinkEntry<T> entry = new LinkEntry<T>(t, null);
     if (head == null) {
       head = entry;
     } else {
       lastLink.tail = entry;
     }
     lastLink = entry;
   }
 }