anchor.diff:     * in a microtask, so there is no danger of side effects occurring due to
      * client callbacks.
      */
  -  bool evaluate(cache.CacheEntry entry) {
  +  bool evaluate(CacheEntry entry) {
       assert(!_completer.isCompleted);
       try {
         T result = _computeValue(entry);
  
positive.code:   @override
    List<Source> getSourcesWithFullName(String path) {
      List<Source> sources = <Source>[];
      MapIterator<AnalysisTarget, cache.CacheEntry> iterator = _cache.iterator();
      while (iterator.moveNext()) {
        AnalysisTarget target = iterator.key;
        if (target is Source && target.fullName == path) {
  
negative.code:   }
  
    @override
    CacheEntry getCacheEntry(AnalysisTarget target) {
      CacheEntry entry = _cache.get(target);
      if (entry == null) {
        entry = new CacheEntry(target);
        _cache.put(entry);
      }
      return entry;
  