}

  @J2ktIncompatible // MapMaker
  private static final class ArbitraryOrderingHolder {
    static final Ordering<@Nullable Object> ARBITRARY_ORDERING = new ArbitraryOrdering();
  }

  @J2ktIncompatible // MapMaker
  @VisibleForTesting
  static class ArbitraryOrdering extends Ordering<@Nullable Object> {

    private final AtomicInteger counter = new AtomicInteger(0);
    private final ConcurrentMap<Object, Integer> uids =

  }

  @J2ktIncompatible // MapMaker
  private static final class ArbitraryOrderingHolder {
    static final Ordering<@Nullable Object> ARBITRARY_ORDERING = new ArbitraryOrdering();
  }

  @J2ktIncompatible // MapMaker
  @VisibleForTesting
  static class ArbitraryOrdering extends Ordering<@Nullable Object> {

    private final AtomicInteger counter = new AtomicInteger(0);
    private final ConcurrentMap<Object, Integer> uids =

  }

  @J2ktIncompatible // ArbitraryOrdering
  public void testArbitrary_withCollisions() {
    List<Integer> list = new ArrayList<>();
    for (int i = 0; i < 50; i++) {
      list.add(i);
    }

    Ordering<Object> arbitrary =
        new ArbitraryOrdering() {
          @Override
          int identityHashCode(Object object) {

  }

  @J2ktIncompatible // ArbitraryOrdering
  public void testArbitrary_withCollisions() {
    List<Integer> list = new ArrayList<>();
    for (int i = 0; i < 50; i++) {
      list.add(i);
    }

    Ordering<Object> arbitrary =
        new ArbitraryOrdering() {
          @Override
          int identityHashCode(Object object) {