ImmutableSet.Builder::add,
          ImmutableSet.Builder::combine,
          ImmutableSet.Builder::build);

  @GwtIncompatible
  private static final Collector<Range<Comparable<?>>, ?, ImmutableRangeSet<Comparable<?>>>
      TO_IMMUTABLE_RANGE_SET =
          Collector.of(
              ImmutableRangeSet::builder,
              ImmutableRangeSet.Builder::add,
              ImmutableRangeSet.Builder::combine,

import java.util.SortedSet;
import java.util.TreeSet;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A wrapper around {@code TreeSet} that aggressively checks to see if elements are mutually
 * comparable. This implementation passes the navigable set test suites.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
public final class SafeTreeSet<E> implements Serializable, NavigableSet<E> {
  @SuppressWarnings("unchecked")

### New unique package

The new [unique](/pkg/unique) package provides facilities for
canonicalizing values (like "interning" or "hash-consing").

Any value of comparable type may be canonicalized with the new
`Make[T]` function, which produces a reference to a canonical copy of
the value in the form of a `Handle[T]`.
Two `Handle[T]` are equal if and only if the values used to produce the
handles are equal, allowing programs to deduplicate values and reduce

   */
  public static <E extends Comparable<E>> MinMaxPriorityQueue<E> create() {
    return new Builder<Comparable<E>>(Ordering.natural()).create();
  }

  /**
   * Creates a new min-max priority queue using natural order, no maximum size, and initially
   * containing the given elements.
   */
  public static <E extends Comparable<E>> MinMaxPriorityQueue<E> create(

 *
 * @author Louis Wasserman
 */
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
@GwtIncompatible
@ElementTypesAreNonnullByDefault
abstract class AbstractRangeSet<C extends Comparable> implements RangeSet<C> {
  AbstractRangeSet() {}

  @Override
  public boolean contains(C value) {
    return rangeContaining(value) != null;
  }

  @Override
  @CheckForNull

import java.util.SortedSet;
import java.util.TreeSet;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A wrapper around {@code TreeSet} that aggressively checks to see if elements are mutually
 * comparable. This implementation passes the navigable set test suites.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
public final class SafeTreeSet<E> implements Serializable, NavigableSet<E> {
  @SuppressWarnings("unchecked")

import java.io.Serializable;

@GwtCompatible(emulated = true)
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
abstract class RangeGwtSerializationDependencies<C extends Comparable> implements Serializable {
  C dummy;

    return unsafeDelegateList((List) Arrays.asList(elements));
  }

  public static <E extends Comparable<? super E>> ImmutableList<E> sortedCopyOf(
      Iterable<? extends E> elements) {
    Comparable<?>[] array = Iterables.toArray(elements, new Comparable<?>[0]);
    checkElementsNotNull((Object[]) array);
    Arrays.sort(array);
    return asImmutableList(array);
  }

  public static void testInvariants(RangeSet<?> rangeSet) {
    testInvariantsInternal(rangeSet);
    testInvariantsInternal(rangeSet.complement());
  }

  private static <C extends Comparable<?>> void testInvariantsInternal(RangeSet<C> rangeSet) {
    assertEquals(rangeSet.asRanges().isEmpty(), rangeSet.isEmpty());
    assertEquals(rangeSet.asDescendingSetOfRanges().isEmpty(), rangeSet.isEmpty());

[]byte                       // does not implement comparable (slices cannot be compared)
interface{}                  // does not implement comparable (see above)
interface{ ~int | ~string }  // type parameter only: implements comparable (int, string types are strictly comparable)
interface{ comparable }      // type parameter only: implements comparable (comparable implements itself)