diff --git a/core/includes/common.inc b/core/includes/common.inc
index f30bcdf..af5dce9 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -28,6 +28,7 @@
 use Drupal\Core\EventSubscriber\HtmlViewSubscriber;
 use Drupal\Core\Routing\GeneratorNotInitializedException;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Template\Markup;
 use Drupal\Core\Render\Element;
 use Drupal\Core\Session\AnonymousUserSession;
 
@@ -915,7 +916,7 @@ function l($text, $path, array $options = array()) {
   // Sanitize the link text if necessary.
   $text = $variables['options']['html'] ? $variables['text'] : String::checkPlain($variables['text']);
 
-  return '<a href="' . $url . '"' . $attributes . '>' . $text . '</a>';
+  return new Markup('<a href="' . $url . '"' . $attributes . '>' . $text . '</a>');
 }
 
 /**
@@ -3481,7 +3482,7 @@ function drupal_render(&$elements, $is_recursive_call = FALSE) {
   }
 
   $elements['#printed'] = TRUE;
-  return $elements['#markup'];
+  return new Markup($elements['#markup']);
 }
 
 /**
@@ -3509,7 +3510,7 @@ function drupal_render_children(&$element, $children_keys = NULL) {
       $output .= drupal_render($element[$key]);
     }
   }
-  return $output;
+  return new Markup($output);
 }
 
 /**
diff --git a/core/includes/form.inc b/core/includes/form.inc
index 42206a4..d23b412 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -15,6 +15,7 @@
 use Drupal\Core\Language\Language;
 use Drupal\Core\Render\Element;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Template\Markup;
 use Drupal\Core\Utility\Color;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 
@@ -1070,7 +1071,7 @@ function template_preprocess_fieldset(&$variables) {
   $variables['attributes']['class'][] = 'form-item';
   $variables['prefix'] = isset($element['#field_prefix']) ? $element['#field_prefix'] : NULL;
   $variables['suffix'] = isset($element['#field_suffix']) ? $element['#field_suffix'] : NULL;
-  $variables['children'] = $element['#children'];
+  $variables['children'] = new Markup($element['#children']);
   $legend_attributes = array();
   if (isset($element['#title_display']) && $element['#title_display'] == 'invisible') {
     $legend_attributes['class'][] = 'visually-hidden';
@@ -1176,7 +1177,7 @@ function template_preprocess_radios(&$variables) {
   if (isset($element['#attributes']['title'])) {
     $variables['attributes']['title'] = $element['#attributes']['title'];
   }
-  $variables['children'] = $element['#children'];
+  $variables['children'] = new Markup($element['#children']);
 }
 
 /**
@@ -1354,7 +1355,7 @@ function template_preprocess_checkboxes(&$variables) {
   if (isset($element['#attributes']['title'])) {
     $variables['attributes']['title'] = $element['#attributes']['title'];
   }
-  $variables['children'] = $element['#children'];
+  $variables['children'] = new Markup($element['#children']);
 }
 
 /**
@@ -2727,7 +2728,7 @@ function template_preprocess_form(&$variables) {
     $element['#attributes']['accept-charset'] = "UTF-8";
   }
   $variables['attributes'] = $element['#attributes'];
-  $variables['children'] = $element['#children'];
+  $variables['children'] = new Markup($element['#children']);
 }
 
 /**
@@ -2943,7 +2944,7 @@ function template_preprocess_form_element(&$variables) {
   $variables['label'] = array('#theme' => 'form_element_label');
   $variables['label'] += array_intersect_key($element, array_flip(array('#id', '#required', '#title', '#title_display')));
 
-  $variables['children'] = $element['#children'];
+  $variables['children'] = new Markup($element['#children']);
 }
 
 /**
diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index e44f13d..df7f438 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -20,6 +20,7 @@
 use Drupal\Core\Page\LinkElement;
 use Drupal\Core\Page\MetaElement;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Template\Markup;
 use Drupal\Core\Template\RenderWrapper;
 use Drupal\Core\Theme\ThemeSettings;
 use Drupal\Component\Utility\NestedArray;
@@ -650,7 +651,8 @@ function _theme($hook, $variables = array()) {
 
   // restore path_to_theme()
   $theme_path = $temp;
-  return (string) $output;
+
+  return new Markup($output);
 }
 
 /**
@@ -1838,7 +1840,7 @@ function template_preprocess_container(&$variables) {
     $element['#attributes']['class'][] = 'form-wrapper';
   }
 
-  $variables['children'] = $element['#children'];
+  $variables['children'] = new Markup($element['#children']);
   $variables['attributes'] = $element['#attributes'];
 }
 
@@ -2078,7 +2080,7 @@ function template_preprocess_page(&$variables) {
 
   // Move some variables to the top level for themer convenience and template cleanliness.
   $variables['show_messages'] = $variables['page']['#show_messages'];
-  $variables['title'] = $variables['page']['#title'];
+  $variables['title'] = new Markup($variables['page']['#title']);
 
   foreach (system_region_list($GLOBALS['theme']) as $region_key => $region_name) {
     if (!isset($variables['page'][$region_key])) {
@@ -2328,7 +2330,7 @@ function template_preprocess_install_page(&$variables) {
  */
 function template_preprocess_region(&$variables) {
   // Create the $content variable that templates expect.
-  $variables['content'] = $variables['elements']['#children'];
+  $variables['content'] = new Markup($variables['elements']['#children']);
   $variables['region'] = $variables['elements']['#region'];
 
   $variables['attributes']['class'][] = 'region';
diff --git a/core/lib/Drupal/Core/CoreServiceProvider.php b/core/lib/Drupal/Core/CoreServiceProvider.php
index fe23fb6..99784f7 100644
--- a/core/lib/Drupal/Core/CoreServiceProvider.php
+++ b/core/lib/Drupal/Core/CoreServiceProvider.php
@@ -101,7 +101,7 @@ public static function registerTwig(ContainerBuilder $container) {
         'cache' => drupal_installation_attempted() ? FALSE : Settings::get('twig_cache', TRUE),
         // @todo Remove in followup issue
         // @see http://drupal.org/node/1712444.
-        'autoescape' => FALSE,
+        'autoescape' => TRUE,
         'debug' => Settings::get('twig_debug', FALSE),
         'auto_reload' => Settings::get('twig_auto_reload', NULL),
       ))
diff --git a/core/lib/Drupal/Core/Template/Attribute.php b/core/lib/Drupal/Core/Template/Attribute.php
index ead5d05..93e4340 100644
--- a/core/lib/Drupal/Core/Template/Attribute.php
+++ b/core/lib/Drupal/Core/Template/Attribute.php
@@ -31,7 +31,7 @@
  *  // Produces <cat class="cat black-cat white-cat black-white-cat" id="socks">
  * @endcode
  */
-class Attribute implements \ArrayAccess, \IteratorAggregate {
+class Attribute extends \Twig_Markup implements \ArrayAccess, \IteratorAggregate {
 
   /**
    * Stores the attribute data.
diff --git a/core/lib/Drupal/Core/Template/Markup.php b/core/lib/Drupal/Core/Template/Markup.php
new file mode 100644
index 0000000..fb53545
--- /dev/null
+++ b/core/lib/Drupal/Core/Template/Markup.php
@@ -0,0 +1,51 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Template\Markup.
+ */
+
+namespace Drupal\Core\Template;
+
+/**
+ * A class that wraps functions to call them while printing in a template.
+ *
+ * To use, one may pass in the function name as a string followed by an array of
+ * arguments to the constructor.
+ * @code
+ * $variables['scripts'] = new Markup('drupal_get_js', array('footer'));
+ * @endcode
+ */
+class Markup extends \Twig_Markup {
+
+  /**
+   * Constructs a Markup object.
+   *
+   * @param string $callback
+   *   The callback function name.
+   * @param array $args
+   *   The arguments to pass to the callback function.
+   */
+  public function __construct($content, $charset = 'UTF-8') {
+    $this->content = $content;
+    $this->charset = $charset;
+  }
+
+  /**
+   * Implements the magic __toString() method.
+   */
+  public function __toString() {
+    return (string) $this->render();
+  }
+
+  /**
+   * Renders the markup.
+   *
+   * @return string
+   *   The results of the callback function.
+   */
+  public function render() {
+    return $this->content;
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Template/RenderWrapper.php b/core/lib/Drupal/Core/Template/RenderWrapper.php
index 7d7770d..58888e6 100644
--- a/core/lib/Drupal/Core/Template/RenderWrapper.php
+++ b/core/lib/Drupal/Core/Template/RenderWrapper.php
@@ -16,7 +16,7 @@
  * $variables['scripts'] = new RenderWrapper('drupal_get_js', array('footer'));
  * @endcode
  */
-class RenderWrapper {
+class RenderWrapper extends \Twig_Markup  {
 
   /**
    * Stores the callback function to be called when rendered.
@@ -52,7 +52,7 @@ public function __construct($callback, array $args = array()) {
    * Implements the magic __toString() method.
    */
   public function __toString() {
-    return $this->render();
+    return (string) $this->render();
   }
 
   /**
diff --git a/core/modules/aggregator/templates/aggregator-feed-source.html.twig b/core/modules/aggregator/templates/aggregator-feed-source.html.twig
index d492904..3dc348b 100644
--- a/core/modules/aggregator/templates/aggregator-feed-source.html.twig
+++ b/core/modules/aggregator/templates/aggregator-feed-source.html.twig
@@ -22,7 +22,7 @@
 <div{{ attributes }}>
   {{ source_icon }}
   {{ source_image }}
-  <p class="feed-description">{{ source_description }}</p>
+  <p class="feed-description">{{ source_description|raw }}</p>
   <dl class="feed-details">
     <dt class="feed-url">{{ 'URL'|t }}</dt>
     <dd>{{ source_url }}</dd>
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeListBuilder.php b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeListBuilder.php
index 723ea71..e8e5243 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeListBuilder.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/CustomBlockTypeListBuilder.php
@@ -10,6 +10,7 @@
 use Drupal\Component\Utility\Xss;
 use Drupal\Core\Config\Entity\ConfigEntityListBuilder;
 use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Template\Markup;
 
 /**
  * Defines a class to build a listing of custom block type entities.
@@ -45,7 +46,7 @@ public function buildHeader() {
    */
   public function buildRow(EntityInterface $entity) {
     $row['type'] = \Drupal::linkGenerator()->generateFromUrl($entity->label(), $entity->urlInfo());
-    $row['description'] = Xss::filterAdmin($entity->description);
+    $row['description'] = new Markup(Xss::filterAdmin($entity->description));
     return $row + parent::buildRow($entity);
   }
 
diff --git a/core/modules/block/custom_block/templates/custom-block-add-list.html.twig b/core/modules/block/custom_block/templates/custom-block-add-list.html.twig
index d2af8e8..615f9ee 100644
--- a/core/modules/block/custom_block/templates/custom-block-add-list.html.twig
+++ b/core/modules/block/custom_block/templates/custom-block-add-list.html.twig
@@ -18,7 +18,7 @@
   <dl class="node-type-list">
     {% for type in types %}
       <dt>{{ type.link }}</dt>
-      <dd>{{ type.description }}</dd>
+      <dd>{{ type.description|raw }}</dd>
     {% endfor %}
   </dl>
 {% endspaceless %}
diff --git a/core/modules/book/lib/Drupal/book/Tests/BookTest.php b/core/modules/book/lib/Drupal/book/Tests/BookTest.php
index cfd7559..b5f0ee8 100644
--- a/core/modules/book/lib/Drupal/book/Tests/BookTest.php
+++ b/core/modules/book/lib/Drupal/book/Tests/BookTest.php
@@ -193,15 +193,15 @@ function checkBookNode(EntityInterface $node, $nodes, $previous = FALSE, $up = F
 
     // Check previous, up, and next links.
     if ($previous) {
-      $this->assertRaw(l('<b>‹</b> ' . $previous->label(), 'node/' . $previous->id(), array('html' => TRUE, 'attributes' => array('rel' => array('prev'), 'title' => t('Go to previous page')))), 'Previous page link found.');
+      $this->assertRaw((string) l('<b>‹</b> ' . $previous->label(), 'node/' . $previous->id(), array('html' => TRUE, 'attributes' => array('rel' => array('prev'), 'title' => t('Go to previous page')))), 'Previous page link found.');
     }
 
     if ($up) {
-      $this->assertRaw(l('Up', 'node/' . $up->id(), array('html'=> TRUE, 'attributes' => array('title' => t('Go to parent page')))), 'Up page link found.');
+      $this->assertRaw((string) l('Up', 'node/' . $up->id(), array('html'=> TRUE, 'attributes' => array('title' => t('Go to parent page')))), 'Up page link found.');
     }
 
     if ($next) {
-      $this->assertRaw(l($next->label() . ' <b>›</b>', 'node/' . $next->id(), array('html'=> TRUE, 'attributes' => array('rel' => array('next'), 'title' => t('Go to next page')))), 'Next page link found.');
+      $this->assertRaw((string) l($next->label() . ' <b>›</b>', 'node/' . $next->id(), array('html'=> TRUE, 'attributes' => array('rel' => array('next'), 'title' => t('Go to next page')))), 'Next page link found.');
     }
 
     // Compute the expected breadcrumb.
diff --git a/core/modules/book/templates/book-node-export-html.html.twig b/core/modules/book/templates/book-node-export-html.html.twig
index 0efa9a7..57b5662 100644
--- a/core/modules/book/templates/book-node-export-html.html.twig
+++ b/core/modules/book/templates/book-node-export-html.html.twig
@@ -18,5 +18,5 @@
 <article id="node-{{ node.id }}" class="section-{{ depth }}">
   <h1 class="book-heading">{{ title }}</h1>
   {{ content }}
-  {{ children }}
+  {{ children|raw }}
 </article>
diff --git a/core/modules/color/templates/color-scheme-form.html.twig b/core/modules/color/templates/color-scheme-form.html.twig
index 694c6f7..eb99781 100644
--- a/core/modules/color/templates/color-scheme-form.html.twig
+++ b/core/modules/color/templates/color-scheme-form.html.twig
@@ -22,5 +22,5 @@
   </div>
   {{ form|without('scheme', 'palette') }}
   <h2>{{ 'Preview'|t }}</h2>
-  {{ html_preview }}
+  {{ html_preview|raw }}
 </div>
diff --git a/core/modules/comment/templates/comment.html.twig b/core/modules/comment/templates/comment.html.twig
index 5fca73b..aafa668 100644
--- a/core/modules/comment/templates/comment.html.twig
+++ b/core/modules/comment/templates/comment.html.twig
@@ -79,8 +79,8 @@
   {{ title_suffix }}
 
   <footer>
-    {{ user_picture }}
-    <p class="submitted">{{ submitted }}</p>
+    {{ user_picture|raw }}
+    <p class="submitted">{{ submitted|raw }}</p>
 
     {#
       Indicate the semantic relationship between parent and child comments
@@ -91,7 +91,7 @@
       <p class="parent visually-hidden">{{ parent }}</p>
     {% endif %}
 
-    {{ permalink }}
+    {{ permalink|raw }}
   </footer>
 
   <div{{ content_attributes }}>
diff --git a/core/modules/contextual/lib/Drupal/contextual/ContextualController.php b/core/modules/contextual/lib/Drupal/contextual/ContextualController.php
index aeee4a6..dd2bed4 100644
--- a/core/modules/contextual/lib/Drupal/contextual/ContextualController.php
+++ b/core/modules/contextual/lib/Drupal/contextual/ContextualController.php
@@ -44,7 +44,7 @@ public function render(Request $request) {
         '#type' => 'contextual_links',
         '#contextual_links' => _contextual_id_to_links($id),
       );
-      $rendered[$id] = drupal_render($element);
+      $rendered[$id] = (string) drupal_render($element);
     }
 
     return new JsonResponse($rendered);
diff --git a/core/modules/datetime/datetime.module b/core/modules/datetime/datetime.module
index 3d13b7b..9a7cf16 100644
--- a/core/modules/datetime/datetime.module
+++ b/core/modules/datetime/datetime.module
@@ -8,6 +8,7 @@
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Datetime\DrupalDateTime;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Template\Markup;
 use Drupal\datetime\DateHelper;
 use Drupal\node\NodeInterface;
 
@@ -241,7 +242,7 @@ function template_preprocess_datetime_wrapper(&$variables) {
     $title_attributes['class'][] = 'form-required';
   }
   $variables['title_attributes'] = new Attribute($title_attributes);
-  $variables['content'] = $element['#children'];
+  $variables['content'] = new Markup($element['#children']);
 }
 
 /**
diff --git a/core/modules/filter/templates/filter-guidelines.html.twig b/core/modules/filter/templates/filter-guidelines.html.twig
index 88a3b47..ecf9b94 100644
--- a/core/modules/filter/templates/filter-guidelines.html.twig
+++ b/core/modules/filter/templates/filter-guidelines.html.twig
@@ -20,6 +20,6 @@
  */
 #}
 <div{{ attributes }}>
-  <h4 class="label">{{ format.name|escape }}</h4>
+  <h4 class="label">{{ format.name }}</h4>
   {{ tips }}
 </div>
diff --git a/core/modules/filter/templates/filter-tips.html.twig b/core/modules/filter/templates/filter-tips.html.twig
index d8f70cb..27a3943 100644
--- a/core/modules/filter/templates/filter-tips.html.twig
+++ b/core/modules/filter/templates/filter-tips.html.twig
@@ -36,7 +36,7 @@
     {% if tip.list|length %}
       <ul class="tips">
       {% for item in tip.list %}
-        <li{{ item.attributes }}>{{ item.tip }}</li>
+        <li{{ item.attributes }}>{{ item.tip|raw }}</li>
       {% endfor %}
       </ul>
     {% endif %}
diff --git a/core/modules/filter/templates/text-format-wrapper.html.twig b/core/modules/filter/templates/text-format-wrapper.html.twig
index b4ff1cc..e2a103e 100644
--- a/core/modules/filter/templates/text-format-wrapper.html.twig
+++ b/core/modules/filter/templates/text-format-wrapper.html.twig
@@ -14,8 +14,8 @@
  */
 #}
 <div class="text-format-wrapper form-item">
-  {{ children }}
+  {{ children|raw }}
   {% if description %}
-    <div{{ attributes }}>{{ description }}</div>
+    <div{{ attributes }}>{{ description|raw }}</div>
   {% endif %}
 </div>
diff --git a/core/modules/forum/lib/Drupal/forum/Tests/ForumTest.php b/core/modules/forum/lib/Drupal/forum/Tests/ForumTest.php
index 6217835..cca701d 100644
--- a/core/modules/forum/lib/Drupal/forum/Tests/ForumTest.php
+++ b/core/modules/forum/lib/Drupal/forum/Tests/ForumTest.php
@@ -564,7 +564,7 @@ private function verifyForums(EntityInterface $node, $admin, $response = 200) {
       '#theme' => 'breadcrumb',
       '#breadcrumb' => $breadcrumb_build,
     );
-    $this->assertRaw(drupal_render($breadcrumb), 'Breadcrumbs were displayed');
+    $this->assertRaw((string) drupal_render($breadcrumb), 'Breadcrumbs were displayed');
 
     // View forum edit node.
     $this->drupalGet('node/' . $node->id() . '/edit');
@@ -624,7 +624,7 @@ private function verifyForumView($forum, $parent = NULL) {
       '#theme' => 'breadcrumb',
       '#breadcrumb' => $breadcrumb_build,
     );
-    $this->assertRaw(drupal_render($breadcrumb), 'Breadcrumbs were displayed');
+    $this->assertRaw((string) drupal_render($breadcrumb), 'Breadcrumbs were displayed');
   }
 
   /**
diff --git a/core/modules/node/lib/Drupal/node/NodeTypeListBuilder.php b/core/modules/node/lib/Drupal/node/NodeTypeListBuilder.php
index 779672a..8ace778 100644
--- a/core/modules/node/lib/Drupal/node/NodeTypeListBuilder.php
+++ b/core/modules/node/lib/Drupal/node/NodeTypeListBuilder.php
@@ -13,6 +13,7 @@
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Template\Markup;
 use Drupal\Component\Utility\Xss;
 use Drupal\Component\Utility\String;
 
@@ -76,7 +77,7 @@ public function buildRow(EntityInterface $entity) {
       'data' => $this->getLabel($entity),
       'class' => array('menu-label'),
     );
-    $row['description'] = Xss::filterAdmin($entity->description);
+    $row['description'] = new Markup(Xss::filterAdmin($entity->description));
     return $row + parent::buildRow($entity);
   }
 
diff --git a/core/modules/node/templates/node-add-list.html.twig b/core/modules/node/templates/node-add-list.html.twig
index 7323896..29ed28c 100644
--- a/core/modules/node/templates/node-add-list.html.twig
+++ b/core/modules/node/templates/node-add-list.html.twig
@@ -19,7 +19,7 @@
   <dl class="node-type-list">
     {% for type in types %}
       <dt>{{ type.add_link }}</dt>
-      <dd>{{ type.description }}</dd>
+      <dd>{{ type.description|raw }}</dd>
     {% endfor %}
   </dl>
 {% else %}
diff --git a/core/modules/node/templates/node.html.twig b/core/modules/node/templates/node.html.twig
index ae1162e..2b47e64 100644
--- a/core/modules/node/templates/node.html.twig
+++ b/core/modules/node/templates/node.html.twig
@@ -88,7 +88,7 @@
   {% if display_submitted %}
     <footer>
       {{ user_picture }}
-      <p class="submitted">{{ submitted }}</p>
+      <p class="submitted">{{ submitted|raw }}</p>
     </footer>
   {% endif %}
 
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php b/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php
index 299f305..fb7dc65 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/Form/SimpletestResultsForm.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Database\Connection;
 use Drupal\Core\Form\FormBase;
+use Drupal\Core\Template\Markup;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\RedirectResponse;
 
@@ -155,7 +156,7 @@ public function buildForm(array $form, array &$form_state, $test_id = NULL) {
       $rows = array();
       foreach ($assertions as $assertion) {
         $row = array();
-        $row[] = $assertion->message;
+        $row[] = new Markup($assertion->message);
         $row[] = $assertion->message_group;
         $row[] = drupal_basename($assertion->file);
         $row[] = $assertion->line;
diff --git a/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsReportsTest.php b/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsReportsTest.php
index 3d8309a..7066e21 100644
--- a/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsReportsTest.php
+++ b/core/modules/statistics/lib/Drupal/statistics/Tests/StatisticsReportsTest.php
@@ -55,7 +55,7 @@ function testPopularContentBlock() {
     $this->assertText('All time', 'Found the all time popular content.');
     $this->assertText('Last viewed', 'Found the last viewed popular content.');
 
-    $this->assertRaw(l($node->label(), 'node/' . $node->id()), 'Found link to visited node.');
+    $this->assertRaw((string) l($node->label(), 'node/' . $node->id()), 'Found link to visited node.');
   }
 
 }
diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php
index caa80a2..d3b21e3 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/RenderTest.php
@@ -277,7 +277,8 @@ function testDrupalRenderBasics() {
     );
 
     foreach($types as $type) {
-      $this->assertIdentical(drupal_render($type['value']), $type['expected'], '"' . $type['name'] . '" input rendered correctly by drupal_render().');
+      $value = drupal_render($type['value']);
+      $this->assertIdentical((string) $value, $type['expected'], '"' . $type['name'] . '" input rendered correctly by drupal_render().');
     }
   }
 
@@ -394,14 +395,14 @@ function testDrupalRenderThemeArguments() {
       '#theme' => 'common_test_foo',
     );
     // Test that defaults work.
-    $this->assertEqual(drupal_render($element), 'foobar', 'Defaults work');
+    $this->assertEqual((string) drupal_render($element), 'foobar', 'Defaults work');
     $element = array(
       '#theme' => 'common_test_foo',
       '#foo' => $this->randomName(),
       '#bar' => $this->randomName(),
     );
     // Tests that passing arguments to the theme function works.
-    $this->assertEqual(drupal_render($element), $element['#foo'] . $element['#bar'], 'Passing arguments to theme functions works');
+    $this->assertEqual((string) drupal_render($element), $element['#foo'] . $element['#bar'], 'Passing arguments to theme functions works');
   }
 
   /**
@@ -470,7 +471,7 @@ function testDrupalRenderPostRenderCache() {
     $element = $test_element;
     $element['#markup'] = '<p>#cache disabled</p>';
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertIdentical($element['#markup'], '<p>overridden</p>', '#markup is overridden.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
     $this->assertIdentical($settings['foo'], 'bar', 'Original JavaScript setting is added to the page.');
@@ -486,7 +487,7 @@ function testDrupalRenderPostRenderCache() {
     $element['#cache'] = array('cid' => 'post_render_cache_test_GET');
     $element['#markup'] = '<p>#cache enabled, GET</p>';
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertTrue(isset($element['#printed']), 'No cache hit');
     $this->assertIdentical($element['#markup'], '<p>overridden</p>', '#markup is overridden.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -509,7 +510,7 @@ function testDrupalRenderPostRenderCache() {
     $element['#cache'] = array('cid' => 'post_render_cache_test_GET');
     $element['#markup'] = '<p>#cache enabled, GET</p>';
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertFalse(isset($element['#printed']), 'Cache hit');
     $this->assertIdentical($element['#markup'], '<p>overridden</p>', '#markup is overridden.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -526,7 +527,7 @@ function testDrupalRenderPostRenderCache() {
     $element['#cache'] = array('cid' => 'post_render_cache_test_POST');
     $element['#markup'] = '<p>#cache enabled, POST</p>';
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertTrue(isset($element['#printed']), 'No cache hit');
     $this->assertIdentical($element['#markup'], '<p>overridden</p>', '#markup is overridden.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -589,7 +590,7 @@ function testDrupalRenderChildrenPostRenderCache() {
     );
     $element = $test_element;
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertTrue(isset($element['#printed']), 'No cache hit');
     $this->assertIdentical($element['#markup'], '<p>overridden</p>', '#markup is overridden.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -635,7 +636,7 @@ function testDrupalRenderChildrenPostRenderCache() {
     drupal_static_reset('_drupal_add_js');
     $element = $test_element;
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertFalse(isset($element['#printed']), 'Cache hit');
     $settings = $this->parseDrupalSettings(drupal_get_js());
     $this->assertIdentical($settings['foo'], 'bar', 'Original JavaScript setting is added to the page.');
@@ -647,7 +648,7 @@ function testDrupalRenderChildrenPostRenderCache() {
     unset($test_element['#cache']);
     $element = $test_element;
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertIdentical($element['#markup'], '<p>overridden</p>', '#markup is overridden.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
     $expected_settings = $context_1 + $context_2 + $context_3;
@@ -667,7 +668,7 @@ function testDrupalRenderChildrenPostRenderCache() {
     $element['#cache']['keys'] = array('simpletest', 'drupal_render', 'children_post_render_cache', 'nested_cache_parent');
     $element['child']['#cache']['keys'] = array('simpletest', 'drupal_render', 'children_post_render_cache', 'nested_cache_child');
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertTrue(isset($element['#printed']), 'No cache hit');
     $this->assertIdentical($element['#markup'], '<p>overridden</p>', '#markup is overridden.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -742,7 +743,7 @@ function testDrupalRenderChildrenPostRenderCache() {
     $element = $test_element;
     $element['#cache']['keys'] = array('simpletest', 'drupal_render', 'children_post_render_cache', 'nested_cache_parent');
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertFalse(isset($element['#printed']), 'Cache hit');
     $settings = $this->parseDrupalSettings(drupal_get_js());
     $this->assertIdentical($settings['foo'], 'bar', 'Original JavaScript setting is added to the page.');
@@ -754,7 +755,7 @@ function testDrupalRenderChildrenPostRenderCache() {
     $element['child']['#cache']['keys'] = array('simpletest', 'drupal_render', 'children_post_render_cache', 'nested_cache_child');
     $element = $element['child'];
     $output = drupal_render($element);
-    $this->assertIdentical($output, '<p>overridden</p>', 'Output is overridden.');
+    $this->assertIdentical((string) $output, '<p>overridden</p>', 'Output is overridden.');
     $this->assertFalse(isset($element['#printed']), 'Cache hit');
     $settings = $this->parseDrupalSettings(drupal_get_js());
     $expected_settings = $context_2 + $context_3;
@@ -790,7 +791,7 @@ function testDrupalRenderRenderCachePlaceholder() {
     drupal_static_reset('_drupal_add_js');
     $element = $test_element;
     $output = drupal_render($element);
-    $this->assertIdentical($output, $expected_output, 'Placeholder was replaced in output');
+    $this->assertIdentical((string) $output, $expected_output, 'Placeholder was replaced in output');
     $settings = $this->parseDrupalSettings(drupal_get_js());
     $this->assertIdentical($settings['common_test'], $context, '#attached is modified; JavaScript setting is added to page.');
 
@@ -803,7 +804,7 @@ function testDrupalRenderRenderCachePlaceholder() {
     $element = $test_element;
     $element['#cache'] = array('cid' => 'render_cache_placeholder_test_GET');
     $output = drupal_render($element);
-    $this->assertIdentical($output, $expected_output, 'Placeholder was replaced in output');
+    $this->assertIdentical((string) $output, $expected_output, 'Placeholder was replaced in output');
     $this->assertTrue(isset($element['#printed']), 'No cache hit');
     $this->assertIdentical($element['#markup'], $expected_output, 'Placeholder was replaced in #markup.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -840,7 +841,7 @@ function testDrupalRenderRenderCachePlaceholder() {
     $element = $test_element;
     $element['#cache'] = array('cid' => 'render_cache_placeholder_test_GET');
     $output = drupal_render($element);
-    $this->assertIdentical($output, $expected_output, 'Placeholder was replaced in output');
+    $this->assertIdentical((string) $output, $expected_output, 'Placeholder was replaced in output');
     $this->assertFalse(isset($element['#printed']), 'Cache hit');
     $this->assertIdentical($element['#markup'], $expected_output, 'Placeholder was replaced in #markup.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -880,7 +881,7 @@ function testDrupalRenderChildElementRenderCachePlaceholder() {
     drupal_static_reset('_drupal_add_js');
     $element = $container;
     $output = drupal_render($element);
-    $this->assertIdentical($output, $expected_output, 'Placeholder was replaced in output');
+    $this->assertIdentical((string) $output, $expected_output, 'Placeholder was replaced in output');
     $settings = $this->parseDrupalSettings(drupal_get_js());
     $this->assertIdentical($settings['common_test'], $context, '#attached is modified; JavaScript setting is added to page.');
 
@@ -899,7 +900,7 @@ function testDrupalRenderChildElementRenderCachePlaceholder() {
     $element['#children'] = drupal_render($child, TRUE);
     // Eventually, drupal_render() gets called on the root element.
     $output = drupal_render($element);
-    $this->assertIdentical($output, $expected_output, 'Placeholder was replaced in output');
+    $this->assertIdentical((string) $output, $expected_output, 'Placeholder was replaced in output');
     $this->assertTrue(isset($element['#printed']), 'No cache hit');
     $this->assertIdentical($element['#markup'], $expected_output, 'Placeholder was replaced in #markup.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
@@ -996,7 +997,7 @@ function testDrupalRenderChildElementRenderCachePlaceholder() {
     $child = &$element['test_element'];
     $element['#children'] = drupal_render($child, TRUE);
     $output = drupal_render($element);
-    $this->assertIdentical($output, $expected_output, 'Placeholder was replaced in output');
+    $this->assertIdentical((string) $output, $expected_output, 'Placeholder was replaced in output');
     $this->assertFalse(isset($element['#printed']), 'Cache hit');
     $this->assertIdentical($element['#markup'], $expected_output, 'Placeholder was replaced in #markup.');
     $settings = $this->parseDrupalSettings(drupal_get_js());
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 9ba1a1c..4b1147b 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -10,6 +10,7 @@
 use Drupal\Core\Extension\Extension;
 use Drupal\Core\Render\Element;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Template\Markup;
 
 /**
  * Recursively check compatibility.
@@ -58,9 +59,9 @@ function template_preprocess_admin_block_content(&$variables) {
       $variables['attributes']['class'][] = 'compact';
     }
     foreach ($variables['content'] as $key => $item) {
-      $variables['content'][$key]['link'] = l($item['title'], $item['link_path'], $item['localized_options']);
+      $variables['content'][$key]['link'] = new Markup(l($item['title'], $item['link_path'], $item['localized_options']));
       if (!$compact && isset($item['description'])) {
-        $variables['content'][$key]['description'] = Xss::filterAdmin($item['description']);
+        $variables['content'][$key]['description'] = new Markup(Xss::filterAdmin($item['description']));
       }
       else {
         $variables['content'][$key]['description'] = FALSE;
diff --git a/core/modules/system/templates/admin-block-content.html.twig b/core/modules/system/templates/admin-block-content.html.twig
index a49bf10..6670bf9 100644
--- a/core/modules/system/templates/admin-block-content.html.twig
+++ b/core/modules/system/templates/admin-block-content.html.twig
@@ -20,7 +20,7 @@
     {% for item in content %}
       <dt>{{ item.link }}</dt>
       {% if item.description %}
-        <dd>{{ item.description }}</dd>
+        <dd>{{ item.description|raw }}</dd>
       {% endif %}
     {% endfor %}
   </dl>
diff --git a/core/modules/system/templates/breadcrumb.html.twig b/core/modules/system/templates/breadcrumb.html.twig
index 5f322f9..d36a426 100644
--- a/core/modules/system/templates/breadcrumb.html.twig
+++ b/core/modules/system/templates/breadcrumb.html.twig
@@ -14,7 +14,7 @@
     <h2 class="visually-hidden">{{ 'You are here'|t }}</h2>
     <ol>
     {% for item in breadcrumb %}
-      <li>{{ item }}</li>
+      <li>{{ item|raw }}</li>
     {% endfor %}
     </ol>
   </nav>
diff --git a/core/modules/system/templates/datetime.html.twig b/core/modules/system/templates/datetime.html.twig
index 25ef788..183b834 100644
--- a/core/modules/system/templates/datetime.html.twig
+++ b/core/modules/system/templates/datetime.html.twig
@@ -25,5 +25,4 @@
  * @see http://www.w3.org/TR/html5-author/the-time-element.html#attr-time-datetime
  */
 #}
-{# @todo Revisit once http://drupal.org/node/1825952 is resolved. #}
-<time{{ attributes }}>{{ html ? text|raw : text|escape }}</time>
+<time{{ attributes }}>{{ html ? text|raw : text }}</time>
diff --git a/core/modules/system/templates/details.html.twig b/core/modules/system/templates/details.html.twig
index 17ea820..6283dc2 100644
--- a/core/modules/system/templates/details.html.twig
+++ b/core/modules/system/templates/details.html.twig
@@ -17,17 +17,17 @@
 #}
 <details{{ attributes }}>
   {%- if title -%}
-    <summary{{ summary_attributes }}>{{ title }}</summary>
+    <summary{{ summary_attributes }}>{{ title|raw }}</summary>
   {%- endif -%}
   <div class="details-wrapper">
     {%- if description -%}
-      <div class="details-description">{{ description }}</div>
+      <div class="details-description">{{ description|raw }}</div>
     {%- endif -%}
     {%- if children -%}
-      {{ children }}
+      {{ children|raw }}
     {%- endif -%}
     {%- if value -%}
-      {{ value }}
+      {{ value|raw }}
     {%- endif -%}
   </div>
 </details>
diff --git a/core/modules/system/templates/dropbutton-wrapper.html.twig b/core/modules/system/templates/dropbutton-wrapper.html.twig
index ca0ff7e..d92bb6e 100644
--- a/core/modules/system/templates/dropbutton-wrapper.html.twig
+++ b/core/modules/system/templates/dropbutton-wrapper.html.twig
@@ -16,7 +16,7 @@
   {% spaceless %}
     <div class="dropbutton-wrapper">
       <div class="dropbutton-widget">
-        {{ children }}
+        {{ children|raw }}
       </div>
     </div>
   {% endspaceless %}
diff --git a/core/modules/system/templates/form-element.html.twig b/core/modules/system/templates/form-element.html.twig
index ea4d90f..bf9b76f 100644
--- a/core/modules/system/templates/form-element.html.twig
+++ b/core/modules/system/templates/form-element.html.twig
@@ -43,7 +43,7 @@
   {% if prefix is not empty %}
     <span class="field-prefix">{{ prefix }}</span>
   {% endif %}
-  {{ children }}
+  {{ children|raw }}
   {% if suffix is not empty %}
     <span class="field-suffix">{{ suffix }}</span>
   {% endif %}
@@ -52,7 +52,7 @@
   {% endif %}
   {% if description.content %}
     <div{{ description.attributes }}>
-      {{ description.content }}
+      {{ description.content|raw }}
     </div>
   {% endif %}
 </div>
diff --git a/core/modules/system/templates/form.html.twig b/core/modules/system/templates/form.html.twig
index 2cd1e95..9bf07f1 100644
--- a/core/modules/system/templates/form.html.twig
+++ b/core/modules/system/templates/form.html.twig
@@ -13,5 +13,5 @@
  */
 #}
 <form{{ attributes }}>
-  {{ children }}
+  {{ children|raw }}
 </form>
diff --git a/core/modules/system/templates/item-list.html.twig b/core/modules/system/templates/item-list.html.twig
index 34e1802..8e0a385 100644
--- a/core/modules/system/templates/item-list.html.twig
+++ b/core/modules/system/templates/item-list.html.twig
@@ -26,7 +26,7 @@
     {%- if items -%}
       <{{ list_type }}{{ attributes }}>
         {%- for item in items -%}
-          <li{{ item.attributes }}>{{ item.value }}</li>
+          <li{{ item.attributes }}>{{ item.value|raw }}</li>
         {%- endfor -%}
       </{{ list_type }}>
     {%- else -%}
diff --git a/core/modules/system/templates/select.html.twig b/core/modules/system/templates/select.html.twig
index 21f32ac..6a24ffd 100644
--- a/core/modules/system/templates/select.html.twig
+++ b/core/modules/system/templates/select.html.twig
@@ -12,4 +12,4 @@
  * @ingroup themeable
  */
 #}
-<select{{ attributes }}>{{ options }}</select>
+<select{{ attributes }}>{{ options|raw }}</select>
diff --git a/core/modules/system/templates/status-messages.html.twig b/core/modules/system/templates/status-messages.html.twig
index 505eb20..e86df24 100644
--- a/core/modules/system/templates/status-messages.html.twig
+++ b/core/modules/system/templates/status-messages.html.twig
@@ -34,11 +34,11 @@
       {% if messages|length > 1 %}
         <ul class="messages__list">
           {% for message in messages %}
-            <li class="messages__item">{{ message }}</li>
+            <li class="messages__item">{{ message|raw }}</li>
           {% endfor %}
         </ul>
       {% else %}
-        {{ messages.0 }}
+        {{ messages.0|raw }}
       {% endif %}
     {% if type == 'error' %}
       </div>
diff --git a/core/modules/system/templates/status-report.html.twig b/core/modules/system/templates/status-report.html.twig
index 7d0d96d..2c17e9c 100644
--- a/core/modules/system/templates/status-report.html.twig
+++ b/core/modules/system/templates/status-report.html.twig
@@ -33,9 +33,9 @@
       </td>
       <td class="status-title">{{ requirement.title }}</td>
       <td class="status-value">
-        {{ requirement.value }}
+        {{ requirement.value|raw }}
         {% if requirement.description %}
-          <div class="description">{{ requirement.description }}</div>
+          <div class="description">{{ requirement.description|raw }}</div>
         {% endif %}
       </td>
     </tr>
diff --git a/core/modules/system/templates/system-themes-page.html.twig b/core/modules/system/templates/system-themes-page.html.twig
index fa0e748..2c18ce3 100644
--- a/core/modules/system/templates/system-themes-page.html.twig
+++ b/core/modules/system/templates/system-themes-page.html.twig
@@ -42,7 +42,7 @@
                 ({{ theme.notes|join(', ') }})
               {%- endif -%}
             </h3>
-            <div class="theme-description">{{ theme.description }}</div>
+            <div class="theme-description">{{ theme.description|raw }}</div>
             {# Display operation links if the theme is compatible. #}
             {% if theme.incompatible %}
               <div class="incompatible">{{ theme.incompatible }}</div>
diff --git a/core/modules/system/templates/vertical-tabs.html.twig b/core/modules/system/templates/vertical-tabs.html.twig
index 5b7298b..5db74a5 100644
--- a/core/modules/system/templates/vertical-tabs.html.twig
+++ b/core/modules/system/templates/vertical-tabs.html.twig
@@ -12,4 +12,4 @@
  * @ingroup themeable
  */
 #}
-<div data-vertical-tabs-panes{{ attributes }}>{{ children }}</div>
+<div data-vertical-tabs-panes{{ attributes }}>{{ children|raw }}</div>
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermIndexTest.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermIndexTest.php
index e79d159..dbe121c 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermIndexTest.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Tests/TermIndexTest.php
@@ -215,6 +215,6 @@ function testTaxonomyTermHierarchyBreadcrumbs() {
 
     // Verify that the page breadcrumbs include a link to the parent term.
     $this->drupalGet('taxonomy/term/' . $term1->id());
-    $this->assertRaw(l($term2->getName(), 'taxonomy/term/' . $term2->id()), 'Parent term link is displayed when viewing the node.');
+    $this->assertRaw((string) l($term2->getName(), 'taxonomy/term/' . $term2->id()), 'Parent term link is displayed when viewing the node.');
   }
 }
diff --git a/core/modules/update/lib/Drupal/update/Tests/UpdateContribTest.php b/core/modules/update/lib/Drupal/update/Tests/UpdateContribTest.php
index 25d8233..dd6a372 100644
--- a/core/modules/update/lib/Drupal/update/Tests/UpdateContribTest.php
+++ b/core/modules/update/lib/Drupal/update/Tests/UpdateContribTest.php
@@ -55,7 +55,7 @@ function testNoReleasesAvailable() {
     // Cannot use $this->standardTests() because we need to check for the
     // 'No available releases found' string.
     $this->assertRaw('<h3>' . t('Drupal core') . '</h3>');
-    $this->assertRaw(l(t('Drupal'), 'http://example.com/project/drupal'));
+    $this->assertRaw((string) l(t('Drupal'), 'http://example.com/project/drupal'));
     $this->assertText(t('Up to date'));
     $this->assertRaw('<h3>' . t('Modules') . '</h3>');
     $this->assertNoText(t('Update available'));
@@ -88,7 +88,7 @@ function testUpdateContribBasic() {
     $this->assertText(t('Up to date'));
     $this->assertRaw('<h3>' . t('Modules') . '</h3>');
     $this->assertNoText(t('Update available'));
-    $this->assertRaw(l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
+    $this->assertRaw((string) l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
   }
 
   /**
@@ -151,8 +151,8 @@ function testUpdateContribOrder() {
     // its own project on the report.
     $this->assertNoRaw(l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project does not appear.');
     // The other two should be listed as projects.
-    $this->assertRaw(l(t('BBB Update test'), 'http://example.com/project/bbb_update_test'), 'Link to bbb_update_test project appears.');
-    $this->assertRaw(l(t('CCC Update test'), 'http://example.com/project/ccc_update_test'), 'Link to bbb_update_test project appears.');
+    $this->assertRaw((string) l(t('BBB Update test'), 'http://example.com/project/bbb_update_test'), 'Link to bbb_update_test project appears.');
+    $this->assertRaw((string) l(t('CCC Update test'), 'http://example.com/project/ccc_update_test'), 'Link to bbb_update_test project appears.');
 
     // We want to make sure we see the BBB project before the CCC project.
     // Instead of just searching for 'BBB Update test' or something, we want
@@ -197,7 +197,7 @@ function testUpdateBaseThemeSecurityUpdate() {
     );
     $this->refreshUpdateStatus($xml_mapping);
     $this->assertText(t('Security update required!'));
-    $this->assertRaw(l(t('Update test base theme'), 'http://example.com/project/update_test_basetheme'), 'Link to the Update test base theme project appears.');
+    $this->assertRaw((string) l(t('Update test base theme'), 'http://example.com/project/update_test_basetheme'), 'Link to the Update test base theme project appears.');
   }
 
   /**
@@ -346,9 +346,9 @@ function testUpdateBrokenFetchURL() {
     $this->assertUniqueText(t('Failed to get available update data for one project.'));
 
     // The other two should be listed as projects.
-    $this->assertRaw(l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
+    $this->assertRaw((string) l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
     $this->assertNoRaw(l(t('BBB Update test'), 'http://example.com/project/bbb_update_test'), 'Link to bbb_update_test project does not appear.');
-    $this->assertRaw(l(t('CCC Update test'), 'http://example.com/project/ccc_update_test'), 'Link to bbb_update_test project appears.');
+    $this->assertRaw((string) l(t('CCC Update test'), 'http://example.com/project/ccc_update_test'), 'Link to bbb_update_test project appears.');
   }
 
   /**
@@ -390,7 +390,7 @@ function testHookUpdateStatusAlter() {
     $this->drupalGet('admin/reports/updates');
     $this->assertRaw('<h3>' . t('Modules') . '</h3>');
     $this->assertText(t('Security update required!'));
-    $this->assertRaw(l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
+    $this->assertRaw((string) l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
 
     // Visit the reports page again without the altering and make sure the
     // status is back to normal.
@@ -398,7 +398,7 @@ function testHookUpdateStatusAlter() {
     $this->drupalGet('admin/reports/updates');
     $this->assertRaw('<h3>' . t('Modules') . '</h3>');
     $this->assertNoText(t('Security update required!'));
-    $this->assertRaw(l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
+    $this->assertRaw((string) l(t('AAA Update test'), 'http://example.com/project/aaa_update_test'), 'Link to aaa_update_test project appears.');
 
     // Turn the altering back on and visit the Update manager UI.
     $update_test_config->set('update_status', $update_status)->save();
diff --git a/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php b/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php
index 7928455..0b26ebc 100644
--- a/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php
+++ b/core/modules/update/lib/Drupal/update/Tests/UpdateCoreTest.php
@@ -56,9 +56,9 @@ function testNormalUpdateAvailable() {
     $this->assertNoText(t('Up to date'));
     $this->assertText(t('Update available'));
     $this->assertNoText(t('Security update required!'));
-    $this->assertRaw(l('7.1', 'http://example.com/drupal-7-1-release'), 'Link to release appears.');
-    $this->assertRaw(l(t('Download'), 'http://example.com/drupal-7-1.tar.gz'), 'Link to download appears.');
-    $this->assertRaw(l(t('Release notes'), 'http://example.com/drupal-7-1-release'), 'Link to release notes appears.');
+    $this->assertRaw((string) l('7.1', 'http://example.com/drupal-7-1-release'), 'Link to release appears.');
+    $this->assertRaw((string) l(t('Download'), 'http://example.com/drupal-7-1.tar.gz'), 'Link to download appears.');
+    $this->assertRaw((string) l(t('Release notes'), 'http://example.com/drupal-7-1-release'), 'Link to release notes appears.');
   }
 
   /**
@@ -71,9 +71,9 @@ function testSecurityUpdateAvailable() {
     $this->assertNoText(t('Up to date'));
     $this->assertNoText(t('Update available'));
     $this->assertText(t('Security update required!'));
-    $this->assertRaw(l('7.2', 'http://example.com/drupal-7-2-release'), 'Link to release appears.');
-    $this->assertRaw(l(t('Download'), 'http://example.com/drupal-7-2.tar.gz'), 'Link to download appears.');
-    $this->assertRaw(l(t('Release notes'), 'http://example.com/drupal-7-2-release'), 'Link to release notes appears.');
+    $this->assertRaw((string) l('7.2', 'http://example.com/drupal-7-2-release'), 'Link to release appears.');
+    $this->assertRaw((string) l(t('Download'), 'http://example.com/drupal-7-2.tar.gz'), 'Link to download appears.');
+    $this->assertRaw((string) l(t('Release notes'), 'http://example.com/drupal-7-2-release'), 'Link to release notes appears.');
   }
 
   /**
diff --git a/core/modules/update/lib/Drupal/update/Tests/UpdateTestBase.php b/core/modules/update/lib/Drupal/update/Tests/UpdateTestBase.php
index 47a6649..5c09710 100644
--- a/core/modules/update/lib/Drupal/update/Tests/UpdateTestBase.php
+++ b/core/modules/update/lib/Drupal/update/Tests/UpdateTestBase.php
@@ -55,7 +55,7 @@ protected function refreshUpdateStatus($xml_map, $url = 'update-test') {
    */
   protected function standardTests() {
     $this->assertRaw('<h3>' . t('Drupal core') . '</h3>');
-    $this->assertRaw(l(t('Drupal'), 'http://example.com/project/drupal'), 'Link to the Drupal project appears.');
+    $this->assertRaw((string) l(t('Drupal'), 'http://example.com/project/drupal'), 'Link to the Drupal project appears.');
     $this->assertNoText(t('No available releases found'));
   }
 }
diff --git a/core/modules/views/templates/views-view-grid.html.twig b/core/modules/views/templates/views-view-grid.html.twig
index a5a813c..bfadb8e 100644
--- a/core/modules/views/templates/views-view-grid.html.twig
+++ b/core/modules/views/templates/views-view-grid.html.twig
@@ -31,7 +31,7 @@
   <div{{ row.attributes }}>
     {% for column in row.content %}
     <div{{ column.attributes }}>
-      {{ column.content }}
+      {{ column.content|raw }}
     </div>
     {% endfor %}
   </div>
@@ -41,7 +41,7 @@
   <div{{ column.attributes }}>
     {% for row in column.content %}
       <div{{ row.attributes }}>
-        {{ row.content }}
+        {{ row.content|raw }}
       </div>
     {% endfor %}
     </div>
diff --git a/core/modules/views/templates/views-view-table.html.twig b/core/modules/views/templates/views-view-table.html.twig
index 6b0b26c..7b1f280 100644
--- a/core/modules/views/templates/views-view-table.html.twig
+++ b/core/modules/views/templates/views-view-table.html.twig
@@ -51,7 +51,7 @@
       <tr>
         {% for column in header %}
           <th{{ column.attributes }} scope="col">
-            {{ column.content }}
+            {{ column.content|raw }}
           </th>
         {% endfor %}
       </tr>
@@ -62,7 +62,7 @@
       <tr{{ row.attributes }}>
         {% for column in row.columns %}
           <td{{ column.attributes }}>
-            {{ column.content }}
+            {{ column.content|raw }}
           </td>
         {% endfor %}
       </tr>
diff --git a/core/modules/views_ui/templates/views-ui-container.html.twig b/core/modules/views_ui/templates/views-ui-container.html.twig
index d45b158..3010a6c 100644
--- a/core/modules/views_ui/templates/views-ui-container.html.twig
+++ b/core/modules/views_ui/templates/views-ui-container.html.twig
@@ -12,4 +12,4 @@
  * @ingroup themeable
  */
 #}
-<div{{ attributes }}>{{ children }}</div>
+<div{{ attributes }}>{{ children|raw }}</div>
diff --git a/core/modules/views_ui/templates/views-ui-display-tab-setting.html.twig b/core/modules/views_ui/templates/views-ui-display-tab-setting.html.twig
index 1c67469..9dc0cfd 100644
--- a/core/modules/views_ui/templates/views-ui-display-tab-setting.html.twig
+++ b/core/modules/views_ui/templates/views-ui-display-tab-setting.html.twig
@@ -20,6 +20,6 @@
     <span class="label">{{ description }}</span>
   {%- endif %}
   {% if settings_links %}
-    {{ settings_links|join('<span class="label">&nbsp;|&nbsp;</span>') }}
+    {{ settings_links|join('<span class="label">&nbsp;|&nbsp;</span>')|raw }}
   {% endif %}
 </div>
diff --git a/core/modules/views_ui/views_ui.theme.inc b/core/modules/views_ui/views_ui.theme.inc
index 430f14a..9d1f07a 100644
--- a/core/modules/views_ui/views_ui.theme.inc
+++ b/core/modules/views_ui/views_ui.theme.inc
@@ -7,6 +7,7 @@
 
 use Drupal\Core\Render\Element;
 use Drupal\Core\Template\Attribute;
+use Drupal\Core\Template\Markup;
 
 /**
  * Prepares variables for Views UI display tab setting templates.
@@ -72,7 +73,7 @@ function template_preprocess_views_ui_display_tab_bucket(&$variables) {
     $variables['attributes']['title'][] = t('Overridden');
   }
 
-  $variables['content'] = $element['#children'];
+  $variables['content'] = new Markup($element['#children']);
   $variables['title'] = $element['#title'];
   $variables['actions'] = !empty($element['#actions']) ? $element['#actions'] : array();
 }
diff --git a/core/themes/bartik/templates/comment.html.twig b/core/themes/bartik/templates/comment.html.twig
index d2c4584..88e1db4 100644
--- a/core/themes/bartik/templates/comment.html.twig
+++ b/core/themes/bartik/templates/comment.html.twig
@@ -66,17 +66,17 @@
 
   <header class="comment-header">
     <div class="attribution">
-      {{ user_picture }}
+      {{ user_picture|raw }}
 
       <div class="submitted">
         <p class="commenter-name">
-          {{ author }}
+          {{ author|raw }}
         </p>
         <p class="comment-time">
-          {{ created }}
+          {{ created|raw }}
         </p>
         <p class="comment-permalink">
-          {{ permalink }}
+          {{ permalink|raw }}
         </p>
         {#
           // Indicate the semantic relationship between parent and child comments
@@ -103,7 +103,7 @@
     <span class="hidden new" data-comment-timestamp="{{ new_indicator_timestamp }}"></span>
 
     {{ title_prefix }}
-    <h3{{ title_attributes }}>{{ title }}</h3>
+    <h3{{ title_attributes }}>{{ title|raw }}</h3>
     {{ title_suffix }}
 
     <div{{ content_attributes }}>
diff --git a/core/themes/bartik/templates/node.html.twig b/core/themes/bartik/templates/node.html.twig
index 2848899..4358954 100644
--- a/core/themes/bartik/templates/node.html.twig
+++ b/core/themes/bartik/templates/node.html.twig
@@ -83,7 +83,7 @@
     {% if display_submitted %}
       <div class="meta submitted">
         {{ user_picture }}
-        {{ submitted }}
+        {{ submitted|raw }}
       </div>
     {% endif %}
   </header>
diff --git a/core/themes/engines/twig/twig.engine b/core/themes/engines/twig/twig.engine
index 1595bf8..e5847cc 100644
--- a/core/themes/engines/twig/twig.engine
+++ b/core/themes/engines/twig/twig.engine
@@ -6,6 +6,7 @@
  */
 
 use Drupal\Core\Extension\Extension;
+use Drupal\Core\Template\Markup;
 
 /**
  * Implements hook_theme().
@@ -138,7 +139,7 @@ function twig_render_var($arg) {
 
   if (is_object($arg)) {
     if (method_exists($arg, '__toString')) {
-      return (string) $arg;
+      return new $arg;
     }
     throw new Exception(t('Object of type "@class" cannot be printed.', array('@class' => get_class($arg))));
   }