}

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

  /**
   * A sensible definition of {@link #tailSet(Object)} in terms of the {@link #tailSet(Object,
   * boolean)} method. If you override {@link #tailSet(Object, boolean)}, you may wish to override
   * {@link #tailSet(Object)} to forward to this implementation.
   */

    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 delegate().subSet(fromElement, toElement);
  }

  @Override
  public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
    return delegate().tailSet(fromElement);
  }

  /**
   * A sensible definition of {@link #contains} in terms of the {@code first()} method of {@link
   * #tailSet}. If you override {@link #tailSet}, you may wish to override {@link #contains} to
   * forward to this implementation.
   *

    NavigableSet<String> set = create();
    SortedSet<String> tailSet = set.tailSet("a");
    assertTrue(tailSet instanceof SynchronizedSortedSet);
    assertSame(set, ((SynchronizedSortedSet<String>) tailSet).mutex);
  }

  public void testTailSet_E_B() {
    NavigableSet<String> set = create();
    NavigableSet<String> tailSet = set.tailSet("a", true);
    assertTrue(tailSet instanceof SynchronizedNavigableSet);

    NavigableSet<String> map = create();
    SortedSet<String> tailSet = map.tailSet("a");
    assertTrue(tailSet instanceof SynchronizedSortedSet);
    assertSame(MUTEX, ((SynchronizedSortedSet<String>) tailSet).mutex);
  }

  public void testTailSet_E_B() {
    NavigableSet<String> map = create();
    NavigableSet<String> tailSet = map.tailSet("a", true);
    assertTrue(tailSet instanceof SynchronizedNavigableSet);

    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() {

    assertThat(set.tailSet(Integer.MIN_VALUE)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.tailSet(1)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.tailSet(2)).containsExactly(2, 3).inOrder();
    assertThat(set.tailSet(3)).containsExactly(3).inOrder();
    assertThat(set.tailSet(Integer.MIN_VALUE, false)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.tailSet(1, false)).containsExactly(2, 3).inOrder();

    assertThat(set.tailSet(Integer.MIN_VALUE)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.tailSet(1)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.tailSet(2)).containsExactly(2, 3).inOrder();
    assertThat(set.tailSet(3)).containsExactly(3).inOrder();
    assertThat(set.tailSet(Integer.MIN_VALUE, false)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.tailSet(1, false)).containsExactly(2, 3).inOrder();

  }

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

  /**
   * A sensible definition of {@link #tailSet(Object)} in terms of the {@link #tailSet(Object,
   * boolean)} method. If you override {@link #tailSet(Object, boolean)}, you may wish to override
   * {@link #tailSet(Object)} to forward to this implementation.
   */

    return delegate().subSet(fromElement, toElement);
  }

  @Override
  public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
    return delegate().tailSet(fromElement);
  }

  /**
   * A sensible definition of {@link #contains} in terms of the {@code first()} method of {@link
   * #tailSet}. If you override {@link #tailSet}, you may wish to override {@link #contains} to
   * forward to this implementation.
   *