Comparator<? super T> comparator,
      @ParametricNullness T lower,
      BoundType lowerType,
      @ParametricNullness T upper,
      BoundType upperType) {
    return new GeneralRange<>(comparator, true, lower, lowerType, true, upper, upperType);
  }

  private final Comparator<? super T> comparator;
  private final boolean hasLowerBound;
  @CheckForNull private final T lowerEndpoint;

      Comparator<? super T> comparator,
      @ParametricNullness T lower,
      BoundType lowerType,
      @ParametricNullness T upper,
      BoundType upperType) {
    return new GeneralRange<>(comparator, true, lower, lowerType, true, upper, upperType);
  }

  private final Comparator<? super T> comparator;
  private final boolean hasLowerBound;
  @CheckForNull private final T lowerEndpoint;