* @since 23.0
   */
  public static ContiguousSet<Long> closedOpen(long lower, long upper) {
    return create(Range.closedOpen(lower, upper), DiscreteDomain.longs());
  }

  final DiscreteDomain<C> domain;

  ContiguousSet(DiscreteDomain<C> domain) {
    super(Ordering.natural());
    this.domain = domain;
  }

  @Override
  public ContiguousSet<C> headSet(C toElement) {

   * @since 23.0
   */
  public static ContiguousSet<Long> closedOpen(long lower, long upper) {
    return create(Range.closedOpen(lower, upper), DiscreteDomain.longs());
  }

  final DiscreteDomain<C> domain;

  ContiguousSet(DiscreteDomain<C> domain) {
    super(Ordering.natural());
    this.domain = domain;
  }

  @Override
  public ContiguousSet<C> headSet(C toElement) {

      extends TestIntegerSortedSetGenerator {
    static final ContiguousSet<Integer> checkedCreate(SortedSet<Integer> elementsSet) {
      List<Integer> elements = new ArrayList<>(elementsSet);
      /*
       * A ContiguousSet can't have holes. If a test demands a hole, it should be changed so that it
       * doesn't need one, or it should be suppressed for ContiguousSet.
       */
      for (int i = 0; i < elements.size() - 1; i++) {

        .addEqualityGroup(
            ContiguousSet.create(Range.closed(1, 3), integers()),
            ContiguousSet.closed(1, 3),
            ContiguousSet.create(Range.closedOpen(1, 4), integers()),
            ContiguousSet.closedOpen(1, 4),
            ContiguousSet.create(Range.openClosed(0, 3), integers()),
            ContiguousSet.create(Range.open(0, 4), integers()),
            ContiguousSet.create(Range.closed(1, 3), NOT_EQUAL_TO_INTEGERS),

        .addEqualityGroup(
            ContiguousSet.create(Range.closed(1, 3), integers()),
            ContiguousSet.closed(1, 3),
            ContiguousSet.create(Range.closedOpen(1, 4), integers()),
            ContiguousSet.closedOpen(1, 4),
            ContiguousSet.create(Range.openClosed(0, 3), integers()),
            ContiguousSet.create(Range.open(0, 4), integers()),
            ContiguousSet.create(Range.closed(1, 3), NOT_EQUAL_TO_INTEGERS),

    super(domain);
    this.range = range;
  }

  private ContiguousSet<C> intersectionInCurrentDomain(Range<C> other) {
    return range.isConnected(other)
        ? ContiguousSet.create(range.intersection(other), domain)
        : new EmptyContiguousSet<C>(domain);
  }

  @Override
  ContiguousSet<C> headSetImpl(C toElement, boolean inclusive) {

    return 0;
  }

  @Override
  public ContiguousSet<C> intersection(ContiguousSet<C> other) {
    return this;
  }

  @Override
  public Range<C> range() {
    throw new NoSuchElementException();
  }

  @Override
  public Range<C> range(BoundType lowerBoundType, BoundType upperBoundType) {
    throw new NoSuchElementException();
  }

  @Override
  ContiguousSet<C> headSetImpl(C toElement, boolean inclusive) {

        long total = 0;
        for (Range<C> range : ranges) {
          if (range.contains(c)) {
            return Ints.saturatedCast(total + ContiguousSet.create(range, domain).indexOf(c));
          } else {
            total += ContiguousSet.create(range, domain).size();
          }
        }
        throw new AssertionError("impossible");
      }
      return -1;
    }

    @Override

   *       other words, {@code ContiguousSet.create(a.canonical(domain), domain).equals(
   *       ContiguousSet.create(a, domain))}
   *   <li>uniqueness: unless {@code a.isEmpty()}, {@code ContiguousSet.create(a,
   *       domain).equals(ContiguousSet.create(b, domain))} implies {@code
   *       a.canonical(domain).equals(b.canonical(domain))}

        .testEquals();
  }

  /** Returns a {@link Set} with a {@link Set#size()} of {@code size}. */
  private static ContiguousSet<Integer> setSize(int size) {
    checkArgument(size >= 0);
    ContiguousSet<Integer> set = ContiguousSet.closedOpen(0, size);
    checkState(set.size() == size);
    return set;
  }

  /**