}
    };
  }

  @GwtIncompatible // NavigableSet
  private static <E extends @Nullable Object> NavigableSet<E> removeOnlyNavigableSet(
      NavigableSet<E> set) {
    return new ForwardingNavigableSet<E>() {
      @Override
      protected NavigableSet<E> delegate() {
        return set;
      }

      @Override

  }

  @Override
  public ContiguousSet<C> headSet(C toElement) {
    return headSetImpl(checkNotNull(toElement), false);
  }

  /**
   * @since 12.0
   */
  @GwtIncompatible // NavigableSet
  @Override
  public ContiguousSet<C> headSet(C toElement, boolean inclusive) {
    return headSetImpl(checkNotNull(toElement), inclusive);
  }

  @Override

  @Override
  int indexOf(@Nullable Object target) {
    return -1;
  }

  @Override
  public UnmodifiableIterator<C> iterator() {
    return emptyIterator();
  }

  @GwtIncompatible // NavigableSet
  @Override
  public UnmodifiableIterator<C> descendingIterator() {
    return emptyIterator();
  }

  @Override
  boolean isPartialView() {
    return false;
  }

  @Override

import com.google.common.testing.SerializableTester;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.NavigableSet;
import java.util.Set;
import java.util.SortedSet;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

public class SafeTreeSetTest extends TestCase {

package com.google.common.collect;

import static com.google.common.collect.Maps.keyOrNull;

import com.google.common.annotations.GwtIncompatible;
import java.util.Iterator;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.NoSuchElementException;
import java.util.SortedMap;
import org.jspecify.annotations.Nullable;

/**
 * A navigable map which forwards all its method calls to another navigable map. Subclasses should

package com.google.common.collect;

import static com.google.common.collect.Maps.keyOrNull;

import com.google.common.annotations.GwtIncompatible;
import java.util.Iterator;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.NoSuchElementException;
import java.util.SortedMap;
import java.util.function.BiFunction;
import org.jspecify.annotations.Nullable;

/**

 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import java.util.Comparator;
import java.util.Iterator;
import java.util.NavigableSet;
import org.jspecify.annotations.Nullable;

/**
 * A sorted multiset which forwards all its method calls to another sorted multiset. Subclasses

import com.google.common.testing.EqualsTester;
import com.google.common.testing.ForwardingWrapperTester;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.NavigableSet;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.NavigableMap;
import java.util.NavigableSet;
import java.util.Objects;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import java.util.Comparator;
import java.util.Iterator;
import java.util.NavigableSet;
import org.jspecify.annotations.Nullable;

/**
 * A sorted multiset which forwards all its method calls to another sorted multiset. Subclasses