assertEquals(ImmutableSet.of(), ArbitraryInstances.get(ImmutableSet.class));
    assertEquals(ImmutableSortedSet.of(), ArbitraryInstances.get(SortedSet.class));
    assertEquals(ImmutableSortedSet.of(), ArbitraryInstances.get(ImmutableSortedSet.class));
    assertEquals(ImmutableList.of(), ArbitraryInstances.get(Collection.class));

          .put(ImmutableList.class, ImmutableList.of())
          .put(Set.class, ImmutableSet.of())
          .put(ImmutableSet.class, ImmutableSet.of())
          .put(SortedSet.class, ImmutableSortedSet.of())
          .put(ImmutableSortedSet.class, ImmutableSortedSet.of())
          .put(NavigableSet.class, Sets.unmodifiableNavigableSet(Sets.newTreeSet()))
          .put(Map.class, ImmutableMap.of())
          .put(ImmutableMap.class, ImmutableMap.of())

    assertFreshInstance(new TypeToken<ImmutableSet<String>>() {});
  }

  public void testImmutableSortedSet() {
    assertFreshInstance(new TypeToken<ImmutableSortedSet<String>>() {});
  }

  public void testImmutableMultiset() {
    assertFreshInstance(new TypeToken<ImmutableSortedSet<String>>() {});
    assertNotInstantiable(new TypeToken<ImmutableMultiset<EmptyEnum>>() {});
  }

  public void testImmutableCollection() {

       * ImmutableSet.Builder but y is an ImmutableSortedSet.Builder (or vice versa). Certainly
       * ImmutableSortedSet.Builder.combine() is written as if its argument will never be a plain
       * ImmutableSet.Builder: It casts immediately to ImmutableSortedSet.Builder.)
       */
      copyIfNecessary();
      this.impl = this.impl.combine(other.impl);

        ImmutableMap<String, String> immutableMap,
        Set<String> set,
        ImmutableSet<Integer> immutableSet,
        SortedSet<Number> sortedSet,
        ImmutableSortedSet<Number> immutableSortedSet,
        Multiset<String> multiset,
        ImmutableMultiset<Integer> immutableMultiset,
        Multimap<String, Integer> multimap,
        ImmutableMultimap<String, Integer> immutableMultimap,

  }

  @Override
  public @Nullable Entry<E> lastEntry() {
    return forward.firstEntry();
  }

  @Override
  public int size() {
    return forward.size();
  }

  @Override
  public ImmutableSortedSet<E> elementSet() {
    return forward.elementSet().descendingSet();
  }

  @Override
  Entry<E> getEntry(int index) {
    return forward.entrySet().asList().reverse().get(index);
  }

  @Override

  }

  @Override
  public @Nullable Entry<E> lastEntry() {
    return forward.firstEntry();
  }

  @Override
  public int size() {
    return forward.size();
  }

  @Override
  public ImmutableSortedSet<E> elementSet() {
    return forward.elementSet().descendingSet();
  }

  @Override
  Entry<E> getEntry(int index) {
    return forward.entrySet().asList().reverse().get(index);
  }

  @Override

        tableSize,
        ((RegularImmutableSet<Integer>) set).table.length);
  }

  public void testCopyOf_copiesImmutableSortedSet() {
    ImmutableSortedSet<String> sortedSet = ImmutableSortedSet.of("a");
    ImmutableSet<String> copy = ImmutableSet.copyOf(sortedSet);
    assertNotSame(sortedSet, copy);
  }

        tableSize,
        ((RegularImmutableSet<Integer>) set).table.length);
  }

  public void testCopyOf_copiesImmutableSortedSet() {
    ImmutableSortedSet<String> sortedSet = ImmutableSortedSet.of("a");
    ImmutableSet<String> copy = ImmutableSet.copyOf(sortedSet);
    assertNotSame(sortedSet, copy);
  }

  public void testToImmutableSet() {

    if (mutable) {
      for (int i = 0; i < reps; i++) {
        dummy += new TreeSet<Integer>(input).first();
      }
    } else {
      for (int i = 0; i < reps; i++) {
        dummy += ImmutableSortedSet.copyOf(input).first();
      }
    }
    return dummy;
  }

  private static final Ordering<Integer> ORDERING = Ordering.natural();