diff --git a/core/lib/Drupal/Core/Template/TwigEnvironment.php b/core/lib/Drupal/Core/Template/TwigEnvironment.php
index eb4f8e5..fc0c994 100644
--- a/core/lib/Drupal/Core/Template/TwigEnvironment.php
+++ b/core/lib/Drupal/Core/Template/TwigEnvironment.php
@@ -27,6 +27,8 @@ class TwigEnvironment extends \Twig_Environment {
    */
   protected $templateClasses;
 
+  protected $templateClassPrefix = '__TwigTemplate_';
+
   /**
    * Constructs a TwigEnvironment object and stores cache and storage
    * internally.
@@ -43,10 +45,6 @@ class TwigEnvironment extends \Twig_Environment {
    *   The options for the Twig environment.
    */
   public function __construct($root, CacheBackendInterface $cache, $twig_extension_hash, \Twig_LoaderInterface $loader = NULL, $options = array()) {
-    // Ensure that twig.engine is loaded, given that it is needed to render a
-    // template because functions like TwigExtension::escapeFilter() are called.
-    require_once $root . '/core/themes/engines/twig/twig.engine';
-
     $this->templateClasses = array();
 
     $options += array(
diff --git a/core/lib/Drupal/Core/Template/TwigExtension.php b/core/lib/Drupal/Core/Template/TwigExtension.php
index 9d6dd1a..2d00ee5 100644
--- a/core/lib/Drupal/Core/Template/TwigExtension.php
+++ b/core/lib/Drupal/Core/Template/TwigExtension.php
@@ -166,7 +166,7 @@ public function getFilters() {
       new \Twig_SimpleFilter('safe_join', [$this, 'safeJoin'], ['needs_environment' => true, 'is_safe' => ['html']]),
 
       // Array filters.
-      new \Twig_SimpleFilter('without', 'twig_without'),
+      new \Twig_SimpleFilter('without', [$this, 'withoutFilter']),
 
       // CSS class and ID filters.
       new \Twig_SimpleFilter('clean_class', '\Drupal\Component\Utility\Html::getClass'),
@@ -551,4 +551,37 @@ public function safeJoin(\Twig_Environment $env, $value, $glue = '') {
     }, $value));
   }
 
+  /**
+   * Removes child elements from a copy of the original array.
+   *
+   * Creates a copy of the renderable array and removes child elements by key
+   * specified through filter's arguments. The copy can be printed without these
+   * elements. The original renderable array is still available and can be used
+   * to print child elements in their entirety in the twig template.
+   *
+   * @param array|object $element
+   *   The parent renderable array to exclude the child items.
+   * @param string[] $args, ...
+   *   The string keys of $element to prevent printing.
+   *
+   * @return array
+   *   The filtered renderable array.
+   */
+  public function withoutFilter($element) {
+    if ($element instanceof \ArrayAccess) {
+      $filtered_element = clone $element;
+    }
+    else {
+      $filtered_element = $element;
+    }
+    $args = func_get_args();
+    unset($args[0]);
+    foreach ($args as $arg) {
+      if (isset($filtered_element[$arg])) {
+        unset($filtered_element[$arg]);
+      }
+    }
+    return $filtered_element;
+  }
+
 }
diff --git a/core/themes/engines/twig/twig.engine b/core/themes/engines/twig/twig.engine
index 30ec511..e937f95 100644
--- a/core/themes/engines/twig/twig.engine
+++ b/core/themes/engines/twig/twig.engine
@@ -117,36 +117,3 @@ function twig_render_template($template_file, array $variables) {
   // This output has already been rendered and is therefore considered safe.
   return Markup::create(implode('', $output));
 }
-
-/**
- * Removes child elements from a copy of the original array.
- *
- * Creates a copy of the renderable array and removes child elements by key
- * specified through filter's arguments. The copy can be printed without these
- * elements. The original renderable array is still available and can be used
- * to print child elements in their entirety in the twig template.
- *
- * @param array|object $element
- *   The parent renderable array to exclude the child items.
- * @param string[] $args, ...
- *   The string keys of $element to prevent printing.
- *
- * @return array
- *   The filtered renderable array.
- */
-function twig_without($element) {
-  if ($element instanceof ArrayAccess) {
-    $filtered_element = clone $element;
-  }
-  else {
-    $filtered_element = $element;
-  }
-  $args = func_get_args();
-  unset($args[0]);
-  foreach ($args as $arg) {
-    if (isset($filtered_element[$arg])) {
-      unset($filtered_element[$arg]);
-    }
-  }
-  return $filtered_element;
-}