}

    @Override
    public int indexOf(@CheckForNull Object object) {
      int index = forwardList.lastIndexOf(object);
      return (index >= 0) ? reverseIndex(index) : -1;
    }

    @Override
    public int lastIndexOf(@CheckForNull Object object) {
      int index = forwardList.indexOf(object);
      return (index >= 0) ? reverseIndex(index) : -1;
    }

    @Override

      int index = indexes.get(i);
      Iterable<String> iterableToAdd = toAdd.get(i);
      boolean expectedChanged = iterableToAdd.iterator().hasNext();
      assertWithMessage(format, iterableToAdd, index)
          .that(Lists.addAllImpl(toTest, index, iterableToAdd))
          .isEqualTo(expectedChanged);
      assertWithMessage(format, iterableToAdd, index)
          .that(toTest)

  }

  @Override
  @CheckForNull
  public E lower(E element) {
    int index = headIndex(element, false) - 1;
    return (index == -1) ? null : elements.get(index);
  }

  @Override
  @CheckForNull
  public E floor(E element) {
    int index = headIndex(element, true) - 1;
    return (index == -1) ? null : elements.get(index);
  }

  @Override
  @CheckForNull
  public E ceiling(E element) {

    setSucceeds(entryIndex, ENDPOINT);
  }

  @Override
  void accessEntry(int index) {
    if (accessOrder) {
      // delete from previous position...
      setSucceeds(getPredecessor(index), getSuccessor(index));
      // ...and insert at the end.
      setSucceeds(lastEntry, index);
      setSucceeds(index, ENDPOINT);
      incrementModCount();
    }
  }

  @Override

   * and ABSENT for empty positions.  We then look up the keys in alternatingKeysAndValues.
   *
   * (The index actually stored is the index of the key in alternatingKeysAndValues, which is
   * double the index of the entry in entrySet.asList.)
   *
   * The basic data structure is described in https://en.wikipedia.org/wiki/Open_addressing.

  static final class ElementSet<E> extends ImmutableSet.Indexed<E> {
    private final List<Entry<E>> entries;
    // TODO(cpovirk): @Weak?
    private final Multiset<E> delegate;

    ElementSet(List<Entry<E>> entries, Multiset<E> delegate) {
      this.entries = entries;
      this.delegate = delegate;
    }

    @Override
    E get(int index) {
      return entries.get(index).getElement();
    }

    @Override

    assertThat(Floats.indexOf(EMPTY, EMPTY)).isEqualTo(0);
    assertThat(Floats.indexOf(ARRAY234, EMPTY)).isEqualTo(0);
    assertThat(Floats.indexOf(EMPTY, ARRAY234)).isEqualTo(-1);
    assertThat(Floats.indexOf(ARRAY234, ARRAY1)).isEqualTo(-1);
    assertThat(Floats.indexOf(ARRAY1, ARRAY234)).isEqualTo(-1);
    assertThat(Floats.indexOf(ARRAY1, ARRAY1)).isEqualTo(0);
    assertThat(Floats.indexOf(ARRAY234, ARRAY234)).isEqualTo(0);

    assertThat(Booleans.indexOf(ARRAY_TRUE, new boolean[0])).isEqualTo(0);
  }

  public void testIndexOf_arrays() {
    assertThat(Booleans.indexOf(EMPTY, false)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE, true)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE_FALSE, true)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE, false)).isEqualTo(0);

    assertThat(Booleans.indexOf(ARRAY_TRUE, new boolean[0])).isEqualTo(0);
  }

  public void testIndexOf_arrays() {
    assertThat(Booleans.indexOf(EMPTY, false)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE, true)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE_FALSE, true)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE, false)).isEqualTo(0);

  public void testIndexOf() {
    assertThat(Shorts.indexOf(EMPTY, (short) 1)).isEqualTo(-1);
    assertThat(Shorts.indexOf(ARRAY1, (short) 2)).isEqualTo(-1);
    assertThat(Shorts.indexOf(ARRAY234, (short) 1)).isEqualTo(-1);
    assertThat(Shorts.indexOf(new short[] {(short) -1}, (short) -1)).isEqualTo(0);
    assertThat(Shorts.indexOf(ARRAY234, (short) 2)).isEqualTo(0);
    assertThat(Shorts.indexOf(ARRAY234, (short) 3)).isEqualTo(1);