* {@link Parser#parseInvocation(ParserRequest)} this method will return {@code true} and invoker should
     * handle this request as "early failure". In these cases, {@link #options()} usually is absent.
     */
    boolean parsingFailed();

    /**
     * Returns {@code true} if this call happens in "embedded" mode.
     *
     * @see ParserRequest#embedded()
     */
    default boolean embedded() {

   * Returns the size of this source in bytes, if the size can be easily determined without actually
   * opening the data stream.
   *
   * <p>The default implementation returns {@link Optional#absent}. Some sources, such as a file,
   * may return a non-absent value. Note that in such cases, it is <i>possible</i> that this method
   * will return a different number of bytes than would be returned by reading all of the bytes (for

   * opening the data stream.
   *
   * <p>The default implementation returns {@link Optional#absent}. Some sources, such as a {@code
   * CharSequence}, may return a non-absent value. Note that in such cases, it is <i>possible</i>
   * that this method will return a different number of chars than would be returned by reading all
   * of the chars.
   *

   * opening the data stream.
   *
   * <p>The default implementation returns {@link Optional#absent}. Some sources, such as a {@code
   * CharSequence}, may return a non-absent value. Note that in such cases, it is <i>possible</i>
   * that this method will return a different number of chars than would be returned by reading all
   * of the chars.
   *

    }
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements.",
        expectedHashCode,
        getSet().hashCode());
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testHashCode_containingNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    int expectedHashCode = 0;

    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    CollectionFeature[] value() default {};

    CollectionFeature[] absent() default {};
  }

    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    SetFeature[] value() default {};

    SetFeature[] absent() default {};
  }

  public void testPollFirst() {
    assertEquals(a, navigableSet.pollFirst());
    assertEquals(values.subList(1, values.size()), copyToList(navigableSet));
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testPollFirstUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> navigableSet.pollFirst());
  }

  @CollectionSize.Require(SEVERAL)

    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    ListFeature[] value() default {};

    ListFeature[] absent() default {};
  }

  @CollectionSize.Require(ZERO)
  public void testIsEmpty_yes() {
    assertTrue("isEmpty() should return true", collection.isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  public void testIsEmpty_no() {
    assertFalse("isEmpty() should return false", collection.isEmpty());
  }