diff --git a/core/lib/Drupal/Core/Template/TwigExtension.php b/core/lib/Drupal/Core/Template/TwigExtension.php
index 637c1e8..e0cd126 100644
--- a/core/lib/Drupal/Core/Template/TwigExtension.php
+++ b/core/lib/Drupal/Core/Template/TwigExtension.php
@@ -16,7 +16,6 @@
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Component\Render\MarkupInterface;
 use Drupal\Core\Datetime\DateFormatter;
-use Drupal\Core\Render\Markup;
 use Drupal\Core\Render\RenderableInterface;
 use Drupal\Core\Render\RendererInterface;
 use Drupal\Core\Routing\UrlGeneratorInterface;
@@ -149,8 +148,8 @@ public function getFunctions() {
   public function getFilters() {
     return array(
       // Translation filters.
-      new \Twig_SimpleFilter('t', [$this, 't'], array('is_safe' => array('html'))),
-      new \Twig_SimpleFilter('trans', [$this, 't'], array('is_safe' => array('html'))),
+      new \Twig_SimpleFilter('t', 't', array('is_safe' => array('html'))),
+      new \Twig_SimpleFilter('trans', 't', array('is_safe' => array('html'))),
       // The "raw" filter is not detectable when parsing "trans" tags. To detect
       // which prefix must be used for translation (@, !, %), we must clone the
       // "raw" filter and give it identifiable names. These filters should only
@@ -178,10 +177,6 @@ public function getFilters() {
     );
   }
 
-  public function t(\Twig_Environment $env, $string) {
-    return new \Twig_Markup(t($string), $env->getCharset());
-  }
-
   /**
    * {@inheritdoc}
    */
@@ -546,11 +541,11 @@ public function renderVar($arg) {
    *   This value is expected to be safe for output and user provided data
    *   should never be used as a glue.
    *
-   * @return \Twig_Markup
+   * @return TwigMarkup
    *   The created imploded string, which is now markup.
    */
   public function safeJoin(\Twig_Environment $env, $value, $glue = '') {
-    return new \Twig_Markup(implode($glue, array_map(function($item) use ($env) {
+    return new TwigMarkup(implode($glue, array_map(function($item) use ($env) {
       // If $item is not marked safe then it will be escaped.
       return $this->escapeFilter($env, $item, 'html', NULL, TRUE);
     }, $value)), $env->getCharset());
diff --git a/core/lib/Drupal/Core/Template/TwigMarkup.php b/core/lib/Drupal/Core/Template/TwigMarkup.php
new file mode 100644
index 0000000..0344a80
--- /dev/null
+++ b/core/lib/Drupal/Core/Template/TwigMarkup.php
@@ -0,0 +1,63 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Template\TwigMarkup.
+ */
+
+namespace Drupal\Core\Template;
+
+use Drupal\Component\Render\MarkupInterface;
+
+/**
+ * A class that defines Twig markup class for Drupal.
+ */
+class TwigMarkup extends \Twig_Markup implements MarkupInterface {
+
+  /**
+   * The string to escape.
+   *
+   * @var string
+   */
+  protected $string;
+
+  /**
+   * The string's character set.
+   *
+   * @var string
+   */
+  protected $charset;
+
+  /**
+   * Constructs an TwigMarkup object.
+   *
+   * @param string $string
+   *   The string to escape. This value will be cast to a string.
+   * @param string $charset
+   */
+  public function __construct($string, $charset = 'utf-8') {
+    parent::__construct($string, $charset);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __toString() {
+    return $this->string;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function count() {
+    return function_exists('mb_get_info') ? mb_strlen($this->content, $this->charset) : strlen($this->content);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function jsonSerialize() {
+    return $this->__toString();
+  }
+
+}
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index efa1f5c..ba725bf 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -211,8 +211,7 @@ function template_preprocess_system_modules_details(&$variables) {
     $module['id'] = $id;
     $module['enable_id'] = $module['enable']['#id'];
 
-    // @todo Remove early rendering and use safe_join in the Twig template once
-    //   https://www.drupal.org/node/2579091 is fixed.
+    // @todo Remove early rendering.
     $renderer = \Drupal::service('renderer');
     $machine_name_render = [
       '#prefix' => '<span dir="ltr" class="table-filter-text-source">',
@@ -222,20 +221,10 @@ function template_preprocess_system_modules_details(&$variables) {
     $module['machine_name'] = $renderer->render($machine_name_render);
 
     if (!empty($module['#requires'])) {
-      $requires = [
-        '#theme' => 'item_list',
-        '#items' => $module['#requires'],
-        '#context' => ['list_style' => 'comma-list'],
-      ];
-      $module['requires'] = $renderer->render($requires);
+      $module['requires'] = $module['#requires'];
     }
     if (!empty($module['#required_by'])) {
-      $required_by = [
-        '#theme' => 'item_list',
-        '#items' => $module['#required_by'],
-        '#context' => ['list_style' => 'comma-list'],
-      ];
-      $module['required_by'] = $renderer->render($required_by);
+      $module['required_by'] = $module['#required_by'];
     }
 
     if (!empty($module['version'])) {
diff --git a/core/modules/system/templates/system-modules-details.html.twig b/core/modules/system/templates/system-modules-details.html.twig
index e431c8e..5ad7812 100644
--- a/core/modules/system/templates/system-modules-details.html.twig
+++ b/core/modules/system/templates/system-modules-details.html.twig
@@ -53,10 +53,10 @@
                     <div class="admin-requirements">{{ 'Version: @module-version'|t({'@module-version': module.version }) }}</div>
                   {% endif %}
                   {% if module.requires %}
-                    <div class="admin-requirements">{{ 'Requires: @module-list'|t({'@module-list': module.requires }) }}</div>
+                    <div class="admin-requirements">{{ 'Requires: @module-list'|t({'@module-list': module.requires|safe_join(', ') }) }}</div>
                   {% endif %}
                   {% if module.required_by %}
-                    <div class="admin-requirements">{{ 'Required by: @module-list'|t({'@module-list': module.required_by }) }}</div>
+                    <div class="admin-requirements">{{ 'Required by: @module-list'|t({'@module-list': module.required_by|safe_join(', ') }) }}</div>
                   {% endif %}
                 </div>
                 {% if module.links %}