Adding type hinting to the private message thread form build form, allowing it...

Adding type hinting to the private message thread form build form, allowing it to be properly extended by other modules.

src/Form/PrivateMessageForm.php

@@ -16,6 +16,7 @@ use Drupal\Core\TypedData\TypedDataManagerInterface;
 use Drupal\private_message\Ajax\PrivateMessageInboxTriggerUpdateCommand;
 use Drupal\private_message\Ajax\PrivateMessageLoadNewMessagesCommand;
 use Drupal\private_message\Entity\PrivateMessageThread;
+use Drupal\private_message\Entity\PrivateMessageThreadInterface;
 use Drupal\private_message\Service\PrivateMessageServiceInterface;
 use Drupal\private_message\Service\PrivateMessageThreadManagerInterface;
 use Drupal\user\UserDataInterface;
@@ -175,7 +176,7 @@ class PrivateMessageForm extends ContentEntityForm {
   /**
    * {@inheritdoc}
    */
-   public function buildForm(array $form, FormStateInterface $form_state, $privateMessageThread = NULL) {
+   public function buildForm(array $form, FormStateInterface $form_state, PrivateMessageThreadInterface $privateMessageThread = NULL) {
     $form = parent::buildForm($form, $form_state);
 
     if ($privateMessageThread) {