private static int hashCodeOf(final @NotNull String oldName) {
    final int hash = oldName.hashCode();
    if (hash == Int2IntMultimap.NO_VALUE) {
      //Int2IntMultimap doesn't allow 0 keys/values, hence replace 0 hash with just any value!=0. Hash doesn't
      // identify name uniquely anyway, hence this replacement just adds another hash collision -- basically,
      // we replaced original String hashcode with our own, which avoids 0 at the cost of slightly higher chances
      // of collisions
      return -1;// any value!=0 will do
    }
    return hash;
  }
private static int hashCodeOf(final @NotNull String oldName)