if (oldEntryForValue != null
        && keyHash == oldEntryForValue.keyHash
        && Objects.equal(key, oldEntryForValue.key)) {
      return key;
    } else if (oldEntryForKey != null && !force) {
      throw new IllegalArgumentException("key already present: " + key);
    }

    /*
     * The ordering here is important: if we deleted the key entry and then the value entry,

  }

  /** Returns the associated key type. */
  @GwtIncompatible
  public Class<K> keyType() {
    return keyTypeOrObjectUnderJ2cl;
  }

  /** Returns the associated value type. */
  @GwtIncompatible
  public Class<V> valueType() {
    return valueTypeOrObjectUnderJ2cl;
  }

  @Override
  K checkKey(K key) {
    return checkNotNull(key);
  }

  @Override

   *
   * @param multimap the presumed-immutable multimap
   * @param sampleKey a key of the same type as that contained by {@code multimap}. {@code multimap}
   *     may or may not have {@code sampleKey} as a key.
   * @param sampleValue a key of the same type as that contained by {@code multimap}. {@code
   *     multimap} may or may not have {@code sampleValue} as a key.
   */
  public static <K extends @Nullable Object, V extends @Nullable Object>

    }
    expectUnchanged();
  }

  @MapFeature.Require({SUPPORTS_PUT, ALLOWS_NULL_KEYS})
  public void testPutAll_nullKeySupported() {
    putAll(containsNullKey);
    expectAdded(containsNullKey.get(0));
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_KEYS)
  public void testPutAll_nullKeyUnsupported() {
    try {
      putAll(containsNullKey);

                    map.putAll(ENTRIES_TO_FILTER);
                    return Maps.filterKeys(map, FILTER_KEYS);
                  }
                })
            .named("Maps.filterKeys[Map, Predicate]")
            .withFeatures(
                MapFeature.ALLOWS_NULL_KEYS,
                MapFeature.ALLOWS_NULL_VALUES,
                MapFeature.ALLOWS_ANY_NULL_QUERIES,

    @Override
    public Collection<UnhashableObject> create(UnhashableObject[] elements) {
      ImmutableMap.Builder<Integer, UnhashableObject> builder = ImmutableMap.builder();
      int key = 1;
      for (UnhashableObject value : elements) {
        builder.put(key++, value);
      }
      return builder.buildOrThrow().values();
    }
  }

  public static class ImmutableMapKeyListGenerator extends TestStringListGenerator {
    @Override

    // count == 0
    segment.setTableEntryForTesting(index, entry);
    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));

    // count == 0
    segment.setTableEntryForTesting(index, entry);
    assertNull(segment.get(key, hash));
    assertFalse(segment.containsKey(key, hash));
    assertFalse(segment.containsValue(value));

    // count == 1
    segment.count++;
    assertSame(value, segment.get(key, hash));
    assertTrue(segment.containsKey(key, hash));
    assertTrue(segment.containsValue(value));

      lastEntry = pred;
    } else {
      setPredecessor(succ, pred);
    }
  }

  @Override
  void insertEntry(
      int entryIndex, @ParametricNullness K key, @ParametricNullness V value, int hash, int mask) {
    super.insertEntry(entryIndex, key, value, hash, mask);
    setSucceeds(lastEntry, entryIndex);
    setSucceeds(entryIndex, ENDPOINT);
  }

  @Override
  void accessEntry(int index) {

 * to the provided {@code standardEquals} method.
 *
 * <p>Each of the {@code standard} methods, where appropriate, use {@link Objects#equal} to test
 * equality for both keys and values. This may not be the desired behavior for map implementations
 * that use non-standard notions of key equality, such as the entry of a {@code SortedMap} whose
 * comparator is not consistent with {@code equals}.
 *