anchor.diff:      bool hasFreeFormal(t) {
         // Ignore nullability wrappers.
         if (_isLegacy(t) || _isNullable(t)) {
  -        return hasFreeFormal(JS<Type>('', '#.type', t));
  +        return hasFreeFormal(JS<Object>('!', '#.type', t));
         }
         if (partials.containsKey(t)) return true;
         // Generic classes and typedefs.
  
positive.code:   var result = isNormalized
        ? _Type(type)
        : (_isLegacy(type)
            ? wrapType(type.type)
            : _canonicalizeNormalizedTypeObject(type));
    JS('', '#[#] = #', type, _typeObject, result);
    return result;
  
negative.code: Object _computeNullable(type) {
    // *? normalizes to ?.
    if (_isLegacy(type)) {
      return nullable(JS<Object>('!', '#.type', type));
    }
    if (_isNullable(type) ||
        _isTop(type) ||
  