anchor.diff:    @override
     void visitListLiteral(ListLiteral node) {
       for (var element in node.elements) {
  -      _recordElementKindAndTokenType('ListLiteral (element)', element);
  +      _recordDataForNode('ListLiteral (element)', element);
       }
       super.visitListLiteral(node);
     }
   
     @override
     void visitMapLiteralEntry(MapLiteralEntry node) {
  -    _recordElementKindAndTokenType('MapLiteralEntry (value)', node.value);
  +    _recordDataForNode('MapLiteralEntry (value)', node.value);
       super.visitMapLiteralEntry(node);
     }
   
  
positive.code: 
    @override
    void visitSpreadElement(SpreadElement node) {
      _recordElementKindAndTokenType(
          'SpreadElement (expression)', node.expression);
      super.visitSpreadElement(node);
    }
  
  
negative.code:   @override
    void visitSetOrMapLiteral(SetOrMapLiteral node) {
      for (var element in node.elements) {
        _recordDataForNode('SetOrMapLiteral (element)', element);
      }
      super.visitSetOrMapLiteral(node);
    }
  