import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A skeleton implementation of a descending multiset. Only needs {@code forwardMultiset()} and
 * {@code entryIterator()}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
abstract class DescendingMultiset<E extends @Nullable Object> extends ForwardingMultiset<E>
    implements SortedMultiset<E> {

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.annotations.VisibleForTesting;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Bimap with zero or more mappings.
 *
 * @author Louis Wasserman
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // uses writeReplace(), not default serialization

   */
  static <T extends @Nullable Object> T[] toArrayImpl(
      @Nullable Object[] src, int offset, int len, T[] dst) {
    checkPositionIndexes(offset, offset + len, src.length);
    if (dst.length < len) {
      dst = newArray(dst, len);
    } else if (dst.length > len) {
      @Nullable Object[] unsoundlyCovariantArray = dst;
      unsoundlyCovariantArray[len] = null;
    }

    @Override
    public boolean equals(@Nullable Object o) {
      return false;
    }

    @Override
    public int hashCode() {
      return super.hashCode();
    }
  }

  /** Test class that returns true if the test object is null */
  private static class InvalidEqualsNullObject {

    @Override
    public boolean equals(@Nullable Object o) {
      return o == this || o == null;
    }

  public final boolean isEmpty() {
    return delegate.isEmpty();
  }

  public final boolean containsKey(@Nullable Object key) {
    return Maps.safeContainsKey(delegate, key);
  }

  public final boolean containsValue(@Nullable Object value) {
    return delegate.containsValue(value);
  }

  public @Nullable V get(@Nullable Object key) {
    return (key == null) ? null : Maps.safeGet(delegate, key);
  }

  @Override

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of the {@code equals}, {@code hashCode}, and {@code toString} methods of {@code
 * Entry}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
abstract class AbstractMapEntry<K extends @Nullable Object, V extends @Nullable Object>
    implements Entry<K, V> {

  @Override
  @ParametricNullness

import java.util.SortedMap;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates sorted maps, containing sample elements, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface TestSortedMapGenerator<K extends @Nullable Object, V extends @Nullable Object>
    extends TestMapGenerator<K, V> {
  @Override

import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Implementation of the {@code equals}, {@code hashCode}, and {@code toString} methods of {@code
 * Entry}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
abstract class AbstractMapEntry<K extends @Nullable Object, V extends @Nullable Object>
    implements Entry<K, V> {

  @Override
  @ParametricNullness

  private static final long serialVersionUID = 0;

  private final Function<? super F, ? extends @Nullable T> function;
  private final Equivalence<T> resultEquivalence;

  FunctionalEquivalence(
      Function<? super F, ? extends @Nullable T> function, Equivalence<T> resultEquivalence) {
    this.function = checkNotNull(function);
    this.resultEquivalence = checkNotNull(resultEquivalence);
  }

  @Override

                "Constructor com.example.Source(java.lang.String): Parameter 0 nullability changed from non-nullable to nullable",
                "Method com.example.SourceKt.invoke(com.example.Source,java.lang.String): Parameter 1 nullability changed from non-nullable to nullable"
            )
            assertHasNoInformation()
        }
    }