Issue #3214829 by Glottus, Christopher Riley, mlncn: No form state passed?

src/Controller/CustomErrorController.php

@@ -4,6 +4,7 @@ namespace Drupal\customerror\Controller;
 
 use Drupal\Core\Controller\ControllerBase;
 use Drupal\Core\Url;
+use Drupal\Core\Form\FormStateInterface;
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 
@@ -92,7 +93,7 @@ class CustomErrorController extends ControllerBase {
       // And that destination isn't going to do anything for us at that point.
       // $path = $this->getRequest()->getPathInfo();
       // $url = \Drupal\Core\Url::fromUserInput($path);
-      // $form_state = new \Drupal\Core\Form\FormState();
+      $form_state = new \Drupal\Core\Form\FormState();
       // $form_state->setRedirectUrl($url);
       // Instead of the above code, we have to do the same thing in ... ah,
       // that's the deal, we have to do it in the submit handler or else it's