diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 1efe91a..d1b5826 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -439,7 +439,7 @@ function _theme($hook, $variables = array()) {
     $variables['theme_hook_suggestions'] = $suggestions;
     // For backwards compatibility, pass 'theme_hook_suggestion' on to the
     // template engine. This is only set when calling a direct suggestion like
-    // '#theme' => 'menu_tree__shortcut_default' when the template exists in the
+    // '#theme' => 'menu__shortcut_default' when the template exists in the
     // current theme.
     if (isset($theme_hook_suggestion)) {
       $variables['theme_hook_suggestion'] = $theme_hook_suggestion;
@@ -1814,22 +1814,10 @@ function template_preprocess_page(&$variables) {
 
   // Pass the main menu and secondary menu to the template as render arrays.
   if (!empty($variables['main_menu'])) {
-    $variables['main_menu']['#heading'] = array(
-      'text' => t('Main menu'),
-      'attributes' => array(
-        'id' => 'links__system_main_menu',
-        'class' => array('visually-hidden'),
-       ),
-    );
+    $variables['main_menu']['#prefix'] = '<h2 id="links__system_main_menu" class="visually-hidden">' . t('Main menu') . '</h2>';
   }
   if (!empty($variables['secondary_menu'])) {
-    $variables['secondary_menu']['#heading'] = array(
-      'text' => t('Secondary menu'),
-      'attributes' => array(
-        'id' => 'links__system_secondary_menu',
-        'class' => array('visually-hidden'),
-      ),
-    );
+    $variables['secondary_menu']['#prefix'] = '<h2 id="links__system_secondary_menu" class="visually-hidden">' . t('Secondary menu') . '</h2>';
   }
 
   if ($node = \Drupal::routeMatch()->getParameter('node')) {
diff --git a/core/modules/system/css/system.theme.css b/core/modules/system/css/system.theme.css
index 184b78a..ca8f188 100644
--- a/core/modules/system/css/system.theme.css
+++ b/core/modules/system/css/system.theme.css
@@ -348,7 +348,7 @@ th.checkbox {
 }
 
 /**
- * Markup generated by theme_menu_tree().
+ * Markup generated by menu.html.twig.
  */
 ul.menu {
   list-style: none outside;
diff --git a/core/themes/bartik/bartik.theme b/core/themes/bartik/bartik.theme
index 27f8973..99c3544 100644
--- a/core/themes/bartik/bartik.theme
+++ b/core/themes/bartik/bartik.theme
@@ -135,22 +135,13 @@ function bartik_preprocess_block(&$variables) {
 }
 
 /**
- * Implements hook_preprocess_HOOK() for menu-tree.html.twig.
- *
- * @see template_preprocess_menu_tree()
+ * Implements hook_preprocess_HOOK() for menu.html.twig.
  */
-function bartik_preprocess_menu_tree(&$variables) {
+function bartik_preprocess_menu(&$variables) {
   $variables['attributes']['class'][] = 'clearfix';
 }
 
 /**
- * Implements THEME_menu_tree__MENUNAME().
- */
-function bartik_menu_tree__shortcut_default($variables) {
-  return '<ul class="menu">' . $variables['tree'] . '</ul>';
-}
-
-/**
  * Implements hook_preprocess_HOOK() for field.html.twig.
  *
  * @see template_preprocess_field()