anchor.diff:      }
       var probe = _cacheGet(cache, recipe);
       if (probe != null) return _castToRti(probe);
  -    var rti = _parseRecipe(universe, environment, recipe);
  +    Rti rti = _parseRecipe(universe, environment, recipe);
       _cacheSet(cache, recipe, rti);
       return rti;
     }
  
positive.code:   }
  
    if (kind == Rti.kindBinding) {
      var base = Rti._getBindingBase(rti);
      var arguments = Rti._getBindingArguments(rti);
      return 'binding(${_rtiToDebugString(base)}, ${_rtiArrayToDebugString(arguments)})';
    }
  
    if (kind == Rti.kindFunction) {
      var returnType = Rti._getReturnType(rti);
      var parameters = Rti._getFunctionParameters(rti);
      return 'function(${_rtiToDebugString(returnType)}, ${functionParametersToString(parameters)})';
    }
  
  
negative.code:   }
  
    // TODO(fishythefish): Support required named parameters.
    Rti returnType = Rti._getReturnType(functionType);
    _FunctionParameters parameters = Rti._getFunctionParameters(functionType);
    var requiredPositional =
        _FunctionParameters._getRequiredPositional(parameters);
    int requiredPositionalLength = _Utils.arrayLength(requiredPositional);
  