diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 9fbca9e..3a45040 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2390,7 +2390,7 @@ function drupal_common_theme() {
     ),
     // From menu.inc.
     'menu' => array(
-      'variables' => array('items' => array()),
+      'variables' => array('items' => array(), 'attributes' => []),
       'template' => 'menu',
     ),
     'menu_local_task' => array(
diff --git a/core/modules/system/templates/menu.html.twig b/core/modules/system/templates/menu.html.twig
index 528f9d7..f24a8bba 100644
--- a/core/modules/system/templates/menu.html.twig
+++ b/core/modules/system/templates/menu.html.twig
@@ -21,9 +21,9 @@
 {#We call a macro which calls itself to render the full tree.
 @see http://twig.sensiolabs.org/doc/tags/macro.html
 #}
-{{ menus.menu_links(items, 0) }}
+{{ menus.menu_links(items, attributes, 0) }}
 
-{% macro menu_links(items, menu_level) %}
+{% macro menu_links(items, attributes, menu_level) %}
   {% import _self as menus %}
   {% if items %}
     {% if menu_level == 0 %}
@@ -35,7 +35,7 @@
         <li{{ item.attributes }}>
           {{ link_from_url(item.title, item.url) }}
           {% if item.below %}
-            {{ menus.menu_links(item.below, menu_level + 1) }}
+            {{ menus.menu_links(item.below, attributes, menu_level + 1) }}
           {% endif %}
         </li>
       {% endfor %}