/**
 * An immutable object that may contain a non-null reference to another object. Each instance of
 * this type either contains a non-null reference, or contains nothing (in which case we say that
 * the reference is "absent"); it is never said to "contain {@code null}".
 *
 * <p>A non-null {@code Optional<T>} reference can be used as a replacement for a nullable {@code T}

        map.put(keyOne, valueOne);
        InternalEntry<Object, Object, ?> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));

        map.put(keyOne, valueOne);
        InternalEntry<Object, Object, ?> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));

      Preconditions.checkState(valueRef instanceof Reference);
      Reference<V> ref = (Reference<V>) valueRef;
      if (ref != null) {
        ref.clear();
      }
    }
  }

  /**
   * Poke into the Cache internals to simulate garbage collection of the given key. This assumes
   * that the given entry is a weak or soft reference, and throws an IllegalStateException if that
   * assumption does not hold.

   *   <li>clearing weak references to unreachable referents
   *   <li>enqueuing weak references to unreachable referents in their reference queue
   * </ul>
   */
  @DoNotMock("Implement with a lambda")
  public interface FinalizationPredicate {
    boolean isDone();
  }

  /**
   * Waits until the given weak reference is cleared, invoking the garbage collector as necessary to

   *   <li>clearing weak references to unreachable referents
   *   <li>enqueuing weak references to unreachable referents in their reference queue
   * </ul>
   */
  @DoNotMock("Implement with a lambda")
  public interface FinalizationPredicate {
    boolean isDone();
  }

  /**
   * Waits until the given weak reference is cleared, invoking the garbage collector as necessary to

            }

            is FirFunctionCall -> {
                val reference = calleeReference as? FirResolvedNamedReference ?: return null
                when (val resolvedSymbol = reference.resolvedSymbol) {
                    is FirConstructorSymbol -> {

      Preconditions.checkState(valueRef instanceof Reference);
      Reference<V> ref = (Reference<V>) valueRef;
      if (ref != null) {
        ref.clear();
      }
    }
  }

  /**
   * Poke into the Cache internals to simulate garbage collection of the given key. This assumes
   * that the given entry is a weak or soft reference, and throws an IllegalStateException if that
   * assumption does not hold.

	for i := range reference.Erasure.Sets {
		if len(reference.Erasure.Sets[i]) != len(format.Erasure.Sets[i]) {
			return fmt.Errorf("Each set should be of same size, expected %d got %d",
				len(reference.Erasure.Sets[i]), len(format.Erasure.Sets[i]))
		}
		for j := range reference.Erasure.Sets[i] {
			if reference.Erasure.Sets[i][j] != format.Erasure.Sets[i][j] {
				return fmt.Errorf("UUID on positions %d:%d do not match with, expected %s got %s: (%w)",

 *  We decide that the LHS is a type reference by checking if the left hand
 *  side is a (qualified) name, and, in case it _is_, resolving that name.
 *
 *  If it resolves to a non-class declaration, it does _not_ refer to a type.
 */
private fun doesDoubleColonUseLHS(lhs: PsiElement): Boolean {
    val reference = when (val inner = lhs.unwrapParenthesesLabelsAndAnnotations()) {