anchor.diff:      }
     }
     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;
   }
   
   /**
  
positive.code:       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,
  
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
  