anchor.diff:      PropertyAccessorElement getter = field.getter;
       PropertyAccessorElement setter = field.setter;
       if (!field.isSynthetic) {
  -      await _addResults(results, field, IndexRelationKind.IS_WRITTEN_BY,
  -          SearchResultKind.WRITE);
  -      await _addResults(results, field, IndexRelationKind.IS_REFERENCED_BY,
  -          SearchResultKind.REFERENCE);
  +      await _addResults(results, field, {
  +        IndexRelationKind.IS_WRITTEN_BY: SearchResultKind.WRITE,
  +        IndexRelationKind.IS_REFERENCED_BY: SearchResultKind.REFERENCE
  +      });
       }
       if (getter != null) {
  -      await _addResults(results, getter, IndexRelationKind.IS_REFERENCED_BY,
  -          SearchResultKind.READ);
  -      await _addResults(results, getter, IndexRelationKind.IS_INVOKED_BY,
  -          SearchResultKind.INVOCATION);
  +      await _addResults(results, getter, {
  +        IndexRelationKind.IS_REFERENCED_BY: SearchResultKind.READ,
  +        IndexRelationKind.IS_INVOKED_BY: SearchResultKind.INVOCATION
  +      });
       }
       if (setter != null) {
  -      await _addResults(results, setter, IndexRelationKind.IS_REFERENCED_BY,
  -          SearchResultKind.WRITE);
  +      await _addResults(results, setter,
  +          {IndexRelationKind.IS_REFERENCED_BY: SearchResultKind.WRITE});
       }
       return results;
     }
  
positive.code:     for (;
          i < index.usedElements.length && index.usedElements[i] == elementId;
          i++) {
        if (index.usedElementKinds[i] == indexKind) {
          int offset = index.usedElementOffsets[i];
          Element enclosingElement =
              _getEnclosingElement(enclosingUnitElement, offset);
          results.add(new SearchResult._(
              null,
              enclosingElement,
              searchKind,
              offset,
              index.usedElementLengths[i],
              true,
  
negative.code:   }
  
    Future<Null> _addResults(List<SearchResult> results, Element element,
        Map<IndexRelationKind, SearchResultKind> relationToResultKind) async {
      String path = element.source.fullName;
  
      // If the file with the element is not known, then the element is not used.
  