* See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;

import com.google.common.annotations.GwtIncompatible;
import java.util.AbstractMap.SimpleImmutableEntry;
import org.jspecify.annotations.Nullable;

/**

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.CollectPreconditions.checkEntryNotNull;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Comparator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.function.Function;

import org.jspecify.annotations.Nullable;

/** Precondition checks useful in collection implementations. */
@GwtCompatible
final class CollectPreconditions {

  static void checkEntryNotNull(@Nullable Object key, @Nullable Object value) {
    if (key == null) {
      throw new NullPointerException("null key in entry: null=" + value);
    } else if (value == null) {