assertSame(this.<String>of(), set.headSet("e"));
  }

  public void testSingle_tailSet() {
    SortedSet<String> set = of("e");
    assertTrue(set.tailSet("c") instanceof ImmutableSortedSet);
    assertThat(set.tailSet("c")).contains("e");
    assertThat(set.tailSet("e")).contains("e");
    assertSame(this.<String>of(), set.tailSet("g"));
  }

  public void testSingle_subSet() {
    SortedSet<String> set = of("e");

      return emptySet(comparator());
    }
    return tailSet(fromElement, fromInclusive).headSet(toElement, toInclusive);
  }

  public ImmutableSortedSet<E> tailSet(E fromElement) {
    checkNotNull(fromElement);
    try {
      return unsafeDelegateSortedSet(sortedDelegate.tailSet(fromElement), true);
    } catch (IllegalArgumentException e) {
      return emptySet(comparator());

    return subSet(fromElement, true, toElement, false);
  }

  @Override
  public SortedSet<E> tailSet(E fromElement) {
    return tailSet(fromElement, true);
  }

  @Override
  public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
    return new SafeTreeSet<>(delegate.tailSet(checkValid(fromElement), inclusive));
  }

  @Override
  public Object[] toArray() {

    ImmutableSortedSet<Integer> asSet = RANGE_SET_ONE.asSet(DiscreteDomain.integers());

    for (int i = 0; i <= 20; i++) {
      assertEquals(asSet.tailSet(i, false), expectedSet.tailSet(i, false));
      assertEquals(asSet.tailSet(i, true), expectedSet.tailSet(i, true));
    }
  }

  public void testAsSetSubSet() {
    ImmutableSortedSet<Integer> expectedSet = ImmutableSortedSet.of(2, 3, 4, 8, 9, 16, 17);

          sortedMap().subMap(fromElement, fromInclusive, toElement, toInclusive));
    }

    @Override
    public NavigableSet<K> tailSet(@ParametricNullness K fromElement) {
      return tailSet(fromElement, true);
    }

    @Override
    public NavigableSet<K> tailSet(@ParametricNullness K fromElement, boolean inclusive) {
      return new NavigableKeySet(sortedMap().tailMap(fromElement, inclusive));
    }
  }

      for (List<Integer> contents : SAMPLE_INPUTS) {
        for (int i = 0; i < 10; i++) {
          assertEquals(
              filter((C) createUnfiltered(contents).tailSet(i), EVEN),
              filter(createUnfiltered(contents), EVEN).tailSet(i));
        }
      }
    }

    @SuppressWarnings("unchecked")
    public void testSubSet() {
      for (List<Integer> contents : SAMPLE_INPUTS) {

      for (List<Integer> contents : SAMPLE_INPUTS) {
        for (int i = 0; i < 10; i++) {
          assertEquals(
              filter((C) createUnfiltered(contents).tailSet(i), EVEN),
              filter(createUnfiltered(contents), EVEN).tailSet(i));
        }
      }
    }

    @SuppressWarnings("unchecked")
    public void testSubSet() {
      for (List<Integer> contents : SAMPLE_INPUTS) {

    return subSetImpl(fromElement, fromInclusive, toElement, toInclusive);
  }

  @Override
  public ContiguousSet<C> tailSet(C fromElement) {
    return tailSetImpl(checkNotNull(fromElement), true);
  }

  /** @since 12.0 */
  @GwtIncompatible // NavigableSet
  @Override
  public ContiguousSet<C> tailSet(C fromElement, boolean inclusive) {
    return tailSetImpl(checkNotNull(fromElement), inclusive);
  }

  /*

    }

    @Override
    public SortedSet<E> headSet(@ParametricNullness E toElement) {
      return multiset().headMultiset(toElement, OPEN).elementSet();
    }

    @Override
    public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
      return multiset().tailMultiset(fromElement, CLOSED).elementSet();
    }

    @Override
    @ParametricNullness
    public E first() {

    return subSetImpl(fromElement, fromInclusive, toElement, toInclusive);
  }

  @Override
  public ContiguousSet<C> tailSet(C fromElement) {
    return tailSetImpl(checkNotNull(fromElement), true);
  }

  /** @since 12.0 */
  @GwtIncompatible // NavigableSet
  @Override
  public ContiguousSet<C> tailSet(C fromElement, boolean inclusive) {
    return tailSetImpl(checkNotNull(fromElement), inclusive);
  }

  /*