anchor.diff:        return suggestions;
       }
       return EMPTY_LIST;
  -  }
  -
  -  void _addArgListSuggestion(Iterable<ParameterElement> requiredParam) {
  -    // DEPRECATED... argument lists are no longer suggested.
  -    // See https://github.com/dart-lang/sdk/issues/25197
  -
  -    // String _getParamType(ParameterElement param) {
  -    //   DartType type = param.type;
  -    //   if (type != null) {
  -    //     return type.displayName;
  -    //   }
  -    //   return 'dynamic';
  -    // }
  -
  -    // StringBuffer completion = new StringBuffer('(');
  -    // List<String> paramNames = new List<String>();
  -    // List<String> paramTypes = new List<String>();
  -    // for (ParameterElement param in requiredParam) {
  -    //   String name = param.name;
  -    //   if (name != null && name.length > 0) {
  -    //     if (completion.length > 1) {
  -    //       completion.write(', ');
  -    //     }
  -    //     completion.write(name);
  -    //     paramNames.add(name);
  -    //     paramTypes.add(_getParamType(param));
  -    //   }
  -    // }
  -    // completion.write(')');
  -    // CompletionSuggestion suggestion = new CompletionSuggestion(
  -    //     CompletionSuggestionKind.ARGUMENT_LIST,
  -    //     DART_RELEVANCE_HIGH,
  -    //     completion.toString(),
  -    //     completion.length,
  -    //     0,
  -    //     false,
  -    //     false);
  -    // suggestion.parameterNames = paramNames;
  -    // suggestion.parameterTypes = paramTypes;
  -    // suggestions.add(suggestion);
     }
   
     void _addDefaultParamSuggestions(Iterable<ParameterElement> parameters,
  
positive.code:     }
    }
    return false;
  }
  
  /**
   * Determine if the completion target is an emtpy argument list.
   */
  bool _isEmptyArgList(DartCompletionRequest request) {
    AstNode node = request.target.containingNode;
    return node is ArgumentList &&
        node.leftParenthesis.next == node.rightParenthesis;
  }
  
  /**
  
negative.code:     Iterable<ParameterElement> requiredParam = parameters.where(
          (ParameterElement p) => p.parameterKind == ParameterKind.REQUIRED);
      int requiredCount = requiredParam.length;
      // TODO (jwren) _isAppendingToArgList can be split into two cases (with and
      // without preceded), then _isAppendingToArgList,
      // _isInsertingToArgListWithNoSynthetic and
  