}

    @Override
    public boolean equals(@Nullable Object object) {
      return equalsImpl(this, object);
    }

    @Override
    public int hashCode() {
      return hashCodeImpl(this);
    }
  }

  private static class FilteredSortedSet<E extends @Nullable Object> extends FilteredSet<E>
      implements SortedSet<E> {

    }

    @Override
    public boolean equals(@Nullable Object object) {
      return equalsImpl(this, object);
    }

    @Override
    public int hashCode() {
      return hashCodeImpl(this);
    }
  }

  private static class FilteredSortedSet<E extends @Nullable Object> extends FilteredSet<E>
      implements SortedSet<E> {