anchor.diff:  
       var symbolizedCachedParameters = {};
       method.optionalParameters.forEach((name, param) => symbolizedCachedParameters[new Symbol(name)] = param);
  -    values.optionalParametersForRequest = _symbolicateParameterValues(symbolizedCachedParameters, values);
  -  }
  -
  -  Map<Symbol, dynamic> _symbolicateParameterValues(Map<Symbol, _HTTPControllerCachedParameter> parameters, _HTTPMethodParameterValues values) {
  -    Map<Symbol, dynamic> symbolicatedParameters = {};
  -
  +    _symbolicateParameterValues(symbolizedCachedParameters, values.optionalParametersForRequest, values._missingQueries, values._missingHeaders);
  +  }
  +
  +  void _symbolicateParameterValues(Map<Symbol, _HTTPControllerCachedParameter> parameters, Map<Symbol, dynamic> symbolicatedParameterValues, List<String> missingQueries, List<String> missingHeaders) {
       parameters.forEach((sym, param) {
         var externalName = param.httpParameter.externalName;
         List<String> value;
  
positive.code:         value = _queryParameters[externalName];
  
          if (value == null && param.httpParameter.isRequired) {
            values._missingQueries.add(externalName);
          }
        } else if (param.httpParameter is HTTPHeader) {
          value = _headerParameters[externalName.toLowerCase()];
  
          if (value == null && param.httpParameter.isRequired) {
            values._missingHeaders.add(externalName);
          }
        }
  
        if (value != null) {
          symbolicatedParameters[sym] = _convertParameterListWithMirror(value, param.typeMirror);
        }
      });
  
      return symbolicatedParameters;
    }
  
    dynamic _convertParameterListWithMirror(List<String> parameterValues, TypeMirror typeMirror) {
  
negative.code:   }
  
    void _symbolicateControllerParameterValues(_HTTPMethodParameterValues values) {
      _symbolicateParameterValues(_controllerLevelParameters[_controller.runtimeType], values.controllerParametersForRequest, values._missingQueries, values._missingHeaders);
    }
  
    void _symbolicateOptionalParameterValues(_HTTPMethodParameterValues values) {
  