@Override
    public @Nullable TypeConstraint tryNegate() {
      if (myInstanceOf.size() == 1 && myNotInstanceOf.isEmpty()) {
        return myInstanceOf.iterator().next().notInstanceOf();
      }
      if (myNotInstanceOf.size() == 1 && myInstanceOf.isEmpty()) {
        return myNotInstanceOf.iterator().next().instanceOf();
      }
      return null;
    }
@Override
    public @Nullable TypeConstraint tryNegate()