assertFreshInstance(new TypeToken<SortedMap<?, String>>() {});
  }

  public void testNavigableMap() {
    assertFreshInstance(new TypeToken<NavigableMap<?, ?>>() {});
  }

  public void testConcurrentMap() {
    assertFreshInstance(new TypeToken<ConcurrentMap<String, ?>>() {});
    assertCanGenerateOnly(
        new TypeToken<ConcurrentMap<EmptyEnum, String>>() {}, Maps.newConcurrentMap());
  }

  @SuppressWarnings("IdentityHashMapBoxing")
  public void testIdentityHashMap() {
    IdentityHashMap<Integer, Integer> map = Maps.newIdentityHashMap();
    assertEquals(emptyMap(), map);
  }

  public void testConcurrentMap() {
    ConcurrentMap<Integer, Integer> map = Maps.newConcurrentMap();
    assertEquals(emptyMap(), map);
  }

  public void testTreeMap() {
    TreeMap<Integer, Integer> map = Maps.newTreeMap();

  @SuppressWarnings("IdentityHashMapBoxing")
  public void testIdentityHashMap() {
    IdentityHashMap<Integer, Integer> map = Maps.newIdentityHashMap();
    assertEquals(emptyMap(), map);
  }

  public void testConcurrentMap() {
    ConcurrentMap<Integer, Integer> map = Maps.newConcurrentMap();
    assertEquals(emptyMap(), map);
  }

  public void testTreeMap() {
    TreeMap<Integer, Integer> map = Maps.newTreeMap();