* iterator tests.
   *
   * @return the new container instance
   * @param newValue the new container instance
   */
  @CanIgnoreReturnValue
  protected C resetContainer(C newValue) {
    container = newValue;
    return container;
  }

  /**
   * @see #expectContents(java.util.Collection)
   * @param elements expected contents of {@link #container}

  }

  @CanIgnoreReturnValue
  @Override
  @SuppressWarnings("nullness") // https://github.com/jspecify/jdk/issues/118
  public boolean replace(K key, V oldValue, V newValue) {
    return delegate().replace(key, oldValue, newValue);
  }

    Integer oldValue = map.putInstance(Integer.class, new Integer(7));
    assertEquals(5, (int) oldValue);

    Integer newValue = map.getInstance(Integer.class);
    assertEquals(7, (int) newValue);

    // Won't compile: map.putInstance(Double.class, new Long(42));
  }

  public void testNull() {

    // different value
    assertThat(segment.replace(key, hash, oldValue, newValue)).isFalse();
    assertThat(segment.count).isEqualTo(1);
    assertThat(segment.get(key, hash)).isSameInstanceAs(newValue);

    // cleared
    entry.setValueReference(oldValueRef);
    assertThat(segment.get(key, hash)).isSameInstanceAs(oldValue);
    oldValueRef.clear();

    // different value
    assertThat(segment.replace(key, hash, oldValue, newValue)).isFalse();
    assertThat(segment.count).isEqualTo(1);
    assertThat(segment.get(key, hash)).isSameInstanceAs(newValue);

    // cleared
    entry.setValueReference(oldValueRef);
    assertThat(segment.get(key, hash)).isSameInstanceAs(oldValue);
    oldValueRef.clear();

    }

    @Override
    @Nullable V getValue(int index) {
      return at(index, columnIndex);
    }

    @Override
    @Nullable V setValue(int index, @Nullable V newValue) {
      return set(index, columnIndex, newValue);
    }
  }

  /**
   * Returns an immutable set of the valid column keys, including those that are associated with
   * null values only.
   *

        }

        @Override
        public boolean remove(Object key, Object value) {
            throw uoe();
        }

        @Override
        public boolean replace(K key, V oldValue, V newValue) {
            throw uoe();
        }

        @Override
        public V replace(K key, V value) {
            throw uoe();
        }

        @Override

    doTestSet(e3());
  }

  private void doTestSet(E newValue) {
    int index = aValidIndex();
    E initialValue = getList().get(index);
    assertEquals(
        "set(i, x) should return the old element at position i.",
        initialValue,
        getList().set(index, newValue));
    assertEquals("After set(i, x), get(i) should return x", newValue, getList().get(index));

           * nullness checker.
           */
          K key = keyFunction.apply(t);
          V newValue = valueFunction.apply(t);
          accum.put(
              checkNotNull(key, "Null key for input %s", t),
              checkNotNull(newValue, "Null value for input %s", t));
        },
        EnumMapAccumulator::combine,
        EnumMapAccumulator::toImmutableMap,

   */
  final void checkNoDuplicate(R rowKey, C columnKey, @Nullable V existingValue, V newValue) {
    checkArgument(
        existingValue == null,
        "Duplicate key: (row=%s, column=%s), values: [%s, %s].",
        rowKey,
        columnKey,
        newValue,
        existingValue);
  }

  // redeclare to satisfy our test for b/310253115
  @Override
  @J2ktIncompatible