anchor.diff:      }
     }
   
  +  static Object? newArrayOrEmpty(int length) => length > 0
  +      ? JS('', 'new Array(#)', length)
  +      : _Universe.sharedEmptyArray(_theUniverse());
  +
     static bool isArray(Object? o) => JS('bool', 'Array.isArray(#)', o);
   
     static int arrayLength(Object? array) => JS('int', '#.length', array);
  
positive.code:   static void addTypeParameterVariances(Object? universe, Object? variances) =>
        _Utils.objectAssign(typeParameterVariances(universe), variances);
  
    static JSArray sharedEmptyArray(Object? universe) =>
        JS('JSArray', '#.#', universe, RtiUniverseFieldNames.sharedEmptyArray);
  
    /// Evaluates [recipe] in the global environment.
    static Rti eval(Object? universe, String recipe, bool normalize) {
  
negative.code:     if (normalize) {
        int length = _Utils.arrayLength(bounds);
        int count = 0;
        Object? typeArguments = _Utils.newArrayOrEmpty(length);
        for (int i = 0; i < length; i++) {
          Rti bound = _Utils.asRti(_Utils.arrayAt(bounds, i));
          if (Rti._getKind(bound) == Rti.kindNever) {
  