*
   * <p><b>Warning:</b> this method silently converts checked exceptions to unchecked exceptions,
   * and should not be used with cache loaders which throw checked exceptions. In such cases use
   * {@link #get} instead.
   *
   * @throws UncheckedExecutionException if an exception was thrown while loading the value. (As
   *     explained in the last paragraph above, this should be an unchecked exception only.)

   * https://github.com/jspecify/jspecify-reference-checker/blob/61aafa4ae52594830cfc2d61c8b113009dbdb045/src/main/java/com/google/jspecify/nullness/NullSpecTransfer.java#L789
   * and https://github.com/jspecify/jspecify/issues/490.
   *
   * (Perhaps it should also have required that its cause was a RuntimeException. However, that
   * would have required that we throw a different kind of exception for wrapping *checked*

   *
   * <p><b>Warning:</b> this method silently converts checked exceptions to unchecked exceptions,
   * and should not be used with cache loaders which throw checked exceptions. In such cases use
   * {@link #get} instead.
   *
   * @throws UncheckedExecutionException if an exception was thrown while loading the value. (As
   *     explained in the last paragraph above, this should be an unchecked exception only.)

  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public void addListener(Runnable listener, Executor executor) {
    checkNotNull(listener, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");
    try {
      executor.execute(listener);
    } catch (Exception e) { // sneaky checked exception
      // ListenableFuture's contract is that it will not throw unchecked exceptions, so log the bad

   * https://github.com/jspecify/jspecify-reference-checker/blob/61aafa4ae52594830cfc2d61c8b113009dbdb045/src/main/java/com/google/jspecify/nullness/NullSpecTransfer.java#L789
   * and https://github.com/jspecify/jspecify/issues/490.
   *
   * (Perhaps it should also have required that its cause was a RuntimeException. However, that
   * would have required that we throw a different kind of exception for wrapping *checked*

    }

    /**
     * Dispatches all listeners {@linkplain #enqueue enqueued} prior to this call, serially and in
     * order.
     */
    @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
    void dispatch() {
      boolean scheduleEventRunner = false;
      synchronized (this) {
        if (!isThreadScheduled) {
          isThreadScheduled = true;
          scheduleEventRunner = true;

      @ParametricNullness E fromElement,
      BoundType fromBoundType,
      @ParametricNullness E toElement,
      BoundType toBoundType) {
    // These are checked elsewhere, but NullPointerTester wants them checked eagerly.
    checkNotNull(fromBoundType);
    checkNotNull(toBoundType);
    return tailMultiset(fromElement, fromBoundType).headMultiset(toElement, toBoundType);
  }

    }
    return null;
  }

  @Override
  public SortedMultiset<E> subMultiset(
      E fromElement, BoundType fromBoundType, E toElement, BoundType toBoundType) {
    // These are checked elsewhere, but NullPointerTester wants them checked eagerly.
    checkNotNull(fromBoundType);
    checkNotNull(toBoundType);
    return tailMultiset(fromElement, fromBoundType).headMultiset(toElement, toBoundType);
  }

      @ParametricNullness E fromElement,
      BoundType fromBoundType,
      @ParametricNullness E toElement,
      BoundType toBoundType) {
    // These are checked elsewhere, but NullPointerTester wants them checked eagerly.
    checkNotNull(fromBoundType);
    checkNotNull(toBoundType);
    return tailMultiset(fromElement, fromBoundType).headMultiset(toElement, toBoundType);
  }

    interface CheckBarrierContext {

        fun <T : LanguageTreeElement> checked(result: CheckedResult<ElementResult<T>>): T {
            val value = result.value
            check(value is Element<T>)
            return value.element
        }

        fun <T> checked(result: CheckedResult<SyntacticResult<T>>): T {
            val value = result.value
            check(value is Syntactic<T>)
            return value.value
        }