Issue #3087868 by Charlie ChX Negyesi, Wim Leers, joachim, smustgrave: Make...

  /**

   * Checks whether this access result indicates access is explicitly allowed.

   *

   * Call this method to check whether someone has access, to convert an access

   * result object to boolean.

   *

   * @return bool

   *   When TRUE then isForbidden() and isNeutral() are FALSE.

   */

  /**

   * Checks whether this access result indicates access is explicitly forbidden.

   *

   * This is a kill switch — both orIf() and andIf() will result in

   * isForbidden() if either results are isForbidden().

   * Call this when optimizing an access checker (for hook_entity_access() or a

   * route requirement): if this is TRUE, the final result will be forbidden and

   * no further checking is necessary.

   *

   * Do not use this method to decide whether someone has access, to convert an

   * access result to boolean: just because this returns FALSE, the end result

   * might be neutral which is not allowed. Always use isAllowed() for this.

   *

   * @return bool

   *   When TRUE then isAllowed() and isNeutral() are FALSE.

   *

   * @return bool

   *   When TRUE then isAllowed() and isForbidden() are FALSE.

   *

   * @internal

   */

  public function isNeutral();