}

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testComputeIfPresent_functionReturnsNull() {
    assertNull(
        "computeIfPresent(present, returnsNull) should return null",
        getMap()
            .computeIfPresent(
                k0(),
                (k, v) -> {
                  assertEquals(k0(), k);
                  assertEquals(v0(), v);

                }));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testComputeIfAbsent_functionReturnsNullNotInserted() {
    assertNull(
        "computeIfAbsent(absent, returnsNull) should return null",
        getMap()
            .computeIfAbsent(
                k3(),
                k -> {
                  assertEquals(k3(), k);
                  return null;
                }));

                }));
    expectUnchanged();
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testComputeIfAbsent_functionReturnsNullNotInserted() {
    assertNull(
        "computeIfAbsent(absent, returnsNull) should return null",
        getMap()
            .computeIfAbsent(
                k3(),
                k -> {
                  assertEquals(k3(), k);
                  return null;
                }));

  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testComputeIfPresent_functionReturnsNull() {
    assertNull(
        "computeIfPresent(present, returnsNull) should return null",
        getMap()
            .computeIfPresent(
                k0(),
                (k, v) -> {
                  assertEquals(k0(), k);
                  assertEquals(v0(), v);

    static FactoryMethodReturnsNullButNotAnnotated returnsNull() {
      return null;
    }
  }

  static class FactoryMethodReturnsNullAndAnnotated {
    private FactoryMethodReturnsNullAndAnnotated() {}

    public static @Nullable FactoryMethodReturnsNullAndAnnotated returnsNull() {
      return null;
    }
  }

  static class FactoryMethodAcceptsNull {