return;
    }

    @SuppressWarnings("unchecked") // verified safe by isInstanceOfThrowableClass
    X castThrowable = (X) throwable;
    T fallbackResult;
    try {
      fallbackResult = doFallback(localFallback, castThrowable);
    } catch (Throwable t) {
      restoreInterruptIfIsInterruptedException(t);
      setException(t);
      return;
    } finally {
      exceptionType = null;