diff -u b/core/lib/Drupal/Core/Render/Element/Actions.php b/core/lib/Drupal/Core/Render/Element/Actions.php
--- b/core/lib/Drupal/Core/Render/Element/Actions.php
+++ b/core/lib/Drupal/Core/Render/Element/Actions.php
@@ -15,11 +15,11 @@
  *
  * Usage example:
  * @code
- * $form['actions'] = array('#type' => 'actions');
- * $form['actions']['submit'] = array(
+ * $form['actions'] = ['#type' => 'actions'];
+ * $form['actions']['submit'] = [
  *   '#type' => 'submit',
  *   '#value' => $this->t('Save'),
- * );
+ * ];
  * @endcode
  *
  * @RenderElement("actions")
@@ -58,13 +58,13 @@
    * @return array
    *   The processed element.
    */
-  public static function processActions(&$element, FormStateInterface $form_state, &$complete_form) {
+  public static function processActions(array &$element, FormStateInterface $form_state, array &$complete_form) {
     $element['#attributes']['class'][] = 'form-actions';
     return $element;
   }
 
   /**
-   * #pre_render callback for #type 'actions'.
+   * Callback #pre_render for #type 'actions'.
    *
    * This callback iterates over all child elements of the #type 'actions'
    * container to look for elements with a #dropbutton property, so as to group
@@ -77,13 +77,15 @@
    * corresponding buttons.
    *
    * @param array $element
+   *   An associative array containing the properties and children of the
+   *   form actions container.
    *
    * @return array
-   *   The processed #type 'actions' element, including individual buttons grouped
-   *   The pre-rendered #type 'actions' element, including individual buttons
-   *   grouped into new #type 'dropbutton' elements.
+   *   The processed #type 'actions' element, including individual buttons
+   *   grouped The pre-rendered #type 'actions' element, including individual
+   *   buttons grouped into new #type 'dropbutton' elements.
    */
-  public static function preRenderActionsDropbutton($element) {
+  public static function preRenderActionsDropbutton(array $element) {
     $dropbuttons = [];
     foreach (Element::children($element, TRUE) as $key) {
       if (isset($element[$key]['#dropbutton'])) {
@@ -99,7 +101,6 @@
         // Add button to the corresponding dropbutton by cloning it.
         // Note: do not prematurely render this as it will break any #attached
         // bubbled metadata that is associated with the button.
-        $button = \Drupal::service('renderer')->renderPlain($element[$key]);
         $dropbuttons[$dropbutton]['#links'][$key] = [
           'title' => $element[$key],
         ];
diff -u b/core/modules/user/src/Plugin/migrate/destination/EntityUser.php b/core/modules/user/src/Plugin/migrate/destination/EntityUser.php
--- b/core/modules/user/src/Plugin/migrate/destination/EntityUser.php
+++ b/core/modules/user/src/Plugin/migrate/destination/EntityUser.php
@@ -125,6 +125,7 @@
 
   /**
    * {@inheritdoc}
+   *
    * @throws \Drupal\migrate\MigrateException
    */
   public function import(Row $row, array $old_destination_id_values = []) {
@@ -141,9 +142,9 @@
   protected function save(ContentEntityInterface $entity, array $old_destination_id_values = []) {
     // Do not overwrite the root account password.
     if ($entity->id() != 1) {
-      // Set the pre_hashed password so that the PasswordItem field does not hash
-      // already hashed passwords. If the md5_passwords configuration option is
-      // set we need to rehash the password and prefix with a U.
+      // Set the pre_hashed password so that the PasswordItem field does not
+      // hash already hashed passwords. If the md5_passwords configuration
+      // option is set we need to rehash the password and prefix with a U.
       // @see \Drupal\Core\Field\Plugin\Field\FieldType\PasswordItem::preSave()
       $entity->pass->pre_hashed = TRUE;
       if (!empty($this->configuration['md5_passwords'])) {