diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index df688ab..9526553 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -8,6 +8,7 @@
 
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 
diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index 4c0e580..2813583 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1681,6 +1681,23 @@ function theme_status_messages($variables) {
 }
 
 /**
+ * Prepares variables for theme_status_messages().
+ *
+ * @param array $variables
+ *   An associative array containing:
+ *   - display: (optional) Set to 'status' or 'error' to display only messages
+ *     of that type.
+ */
+function template_preprocess_status_messages(&$variables) {
+  $variables['messages_display'] = drupal_get_messages($variables['display']);
+  $variables['status_headings'] = array(
+    'status' => t('Status message'),
+    'error' => t('Error message'),
+    'warning' => t('Warning message'),
+  );
+}
+
+/**
  * Returns HTML for a link.
  *
  * All Drupal code that outputs a link should call the l() function. That
@@ -3149,6 +3166,7 @@ function drupal_common_theme() {
     ),
     'status_messages' => array(
       'variables' => array('display' => NULL),
+      'template' => 'status-messages',
     ),
     'link' => array(
       'variables' => array('text' => NULL, 'path' => NULL, 'options' => array()),
diff --git a/core/modules/system/templates/status-messages.html.twig b/core/modules/system/templates/status-messages.html.twig
new file mode 100644
index 0000000..dbcf5fb
--- /dev/null
+++ b/core/modules/system/templates/status-messages.html.twig
@@ -0,0 +1,37 @@
+{#
+/**
+ * @file
+ * Returns HTML for status and/or error messages, grouped by type.
+ *
+ * An invisible heading identifies the messages for assistive technology.
+ * Sighted users see a colored box. See http://www.w3.org/TR/WCAG-TECHS/H69.html
+ * for info.
+ *
+ * Available variables:
+ * - messages_display: List of messages of all statuses which attempts to be
+ *   displayed.
+ * - status_heading: List of all status types.
+ *
+ * @see template_preprocess()
+ * @see template_preprocess_status_messages()
+ *
+ * @ingroup themeable
+ */
+#}
+
+{% for type, messages in messages_display %}
+  <div class="messages {{ type }}">
+    {% if type in status_heading %}
+      <h2 class="element-invisible">{{ status_heading[type] }}</h2>
+    {% endif %}
+    {% if messages|length > 1 %}
+      <ul>
+        {% for message in messages %}
+          <li>{{ message }}</li>
+        {% endfor %}
+      </ul>
+    {% else %}
+      {{ messages[0] }}
+    {% endif %}
+  </div>
+{% endfor %}