diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index e7ec8df..f398719 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -2039,19 +2039,6 @@ function template_preprocess_field(&$variables, $hook) {
   // readers.
   $variables['label'] = String::checkPlain($element['#title']);
 
-  // We want other preprocess functions and the theme implementation to have
-  // fast access to the field item render arrays. The item render array keys
-  // (deltas) should always be numerically indexed starting from 0, and looping
-  // on those keys is faster than calling
-  // \Drupal\Core\Render\Element::children() or looping on all keys within
-  // $element, since that requires traversal of all element properties.
-  $variables['items'] = array();
-  $delta = 0;
-  while (!empty($element[$delta])) {
-    $variables['items'][$delta] = $element[$delta];
-    $delta++;
-  }
-
   // Add default CSS classes. Since there can be many fields rendered on a page,
   // save some overhead by calling strtr() directly instead of
   // drupal_html_class().
@@ -2065,6 +2052,7 @@ function template_preprocess_field(&$variables, $hook) {
     'field-type-' . $variables['field_type_css'],
     'field-label-' . $element['#label_display'],
   );
+
   // Add a "clearfix" class to the wrapper since we float the label and the
   // field items in field.module.css if the label is inline.
   if ($element['#label_display'] == 'inline') {
@@ -2081,15 +2069,26 @@ function template_preprocess_field(&$variables, $hook) {
     $default_attributes = new Attribute;
   }
 
-  // Modules (e.g., rdf.module) can add field item attributes (to
-  // $item->_attributes) within hook_entity_prepare_view(). Some field
-  // formatters move those attributes into some nested formatter-specific
-  // element in order have them rendered on the desired HTML element (e.g., on
-  // the <a> element of a field item being rendered as a link). Other field
-  // formatters leave them within $element['#items'][$delta]['_attributes'] to
-  // be rendered on the item wrappers provided by field.html.twig.
-  foreach ($variables['items'] as $delta => $item) {
-    $variables['item_attributes'][$delta] = !empty($element['#items'][$delta]->_attributes) ? new Attribute($element['#items'][$delta]->_attributes) : clone($default_attributes);
+  // We want other preprocess functions and the theme implementation to have
+  // fast access to the field item render arrays. The item render array keys
+  // (deltas) should always be numerically indexed starting from 0, and looping
+  // on those keys is faster than calling element_children() or looping on all
+  // keys within $element, since that requires traversal of all element
+  // properties.
+  $variables['items'] = array();
+  $delta = 0;
+  while (!empty($element[$delta])) {
+    $variables['items'][$delta]['content'] = $element[$delta];
+
+    // Modules (e.g., rdf.module) can add field item attributes (to
+    // $item->_attributes) within hook_entity_prepare_view(). Some field
+    // formatters move those attributes into some nested formatter-specific
+    // element in order have them rendered on the desired HTML element (e.g., on
+    // the <a> element of a field item being rendered as a link). Other field
+    // formatters leave them within $element['#items'][$delta]['_attributes'] to
+    // be rendered on the item wrappers provided by field.html.twig.
+    $variables['items'][$delta]['#attributes'] = !empty($element['#items'][$delta]->_attributes) ? new Attribute($element['#items'][$delta]->_attributes) : clone($default_attributes);
+    $delta++;
   }
 }
 
diff --git a/core/lib/Drupal/Core/Render/Element/MoreLink.php b/core/lib/Drupal/Core/Render/Element/MoreLink.php
index 4f7e90c..6551abb 100644
--- a/core/lib/Drupal/Core/Render/Element/MoreLink.php
+++ b/core/lib/Drupal/Core/Render/Element/MoreLink.php
@@ -24,7 +24,7 @@ public function getInfo() {
       '#title' => $this->t('More'),
       '#theme_wrappers' => array(
         'container' => array(
-          '#attributes' => array('class' => 'more-link'),
+          '#attributes' => array('class' => array('more-link')),
         ),
       ),
     ) + $info;
diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 5b1ed9b..75572ad 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -841,7 +841,7 @@ function comment_preprocess_field(&$variables) {
     $variables['title_attributes']['class'][] = 'title';
 
     // Append additional attributes (eg. RDFa) from the first field item.
-    $variables['attributes'] += $variables['item_attributes'][0]->storage();
+    $variables['attributes'] += $variables['items'][0]['#attributes']->storage();
 
     // Create separate variables for the comments and comment form.
     $variables['comments'] = $element[0]['comments'];
diff --git a/core/modules/node/templates/field--node--title.html.twig b/core/modules/node/templates/field--node--title.html.twig
index 25432c0..204e0b8 100644
--- a/core/modules/node/templates/field--node--title.html.twig
+++ b/core/modules/node/templates/field--node--title.html.twig
@@ -8,11 +8,17 @@
  *
  * Available variables:
  * - attributes: HTML attributes for the containing span element.
- * - items: List of all the field items.
+ * - items: List of all the field items. Each item contains:
+ *   - #attributes: List of HTML attributes for each item.
+ *   - content: The field item content.
  *
  * @see field.html.twig
  *
  * @ingroup themeable
  */
 #}
-<span{{ attributes }}>{{ items }}</span>
+<span{{ attributes }}>
+  {%- for item in items -%}
+    {{ item.content }}
+  {%- endfor -%}
+</span>
diff --git a/core/modules/system/css/system.admin.css b/core/modules/system/css/system.admin.css
index 853ded2..2c1269b 100644
--- a/core/modules/system/css/system.admin.css
+++ b/core/modules/system/css/system.admin.css
@@ -28,7 +28,7 @@ div.admin .expert-link {
 }
 
 /**
- * Markup generated by theme_system_compact_link().
+ * System compact link: to toggle the display of description text.
  */
 .compact-link {
   margin: 0 0 0.5em 0;
diff --git a/core/modules/system/src/Tests/Common/RenderElementTypesTest.php b/core/modules/system/src/Tests/Common/RenderElementTypesTest.php
index 6d83838..7a524ad 100644
--- a/core/modules/system/src/Tests/Common/RenderElementTypesTest.php
+++ b/core/modules/system/src/Tests/Common/RenderElementTypesTest.php
@@ -184,4 +184,50 @@ function testMoreLink() {
     }
   }
 
+  /**
+   * Tests system #type 'system_compact_link'.
+   */
+  function testSystemCompactLink() {
+    $elements = array(
+      array(
+        'name' => "#type 'system_compact_link' when admin compact mode is off",
+        'value' => array(
+          '#type' => 'system_compact_link',
+        ),
+        'expected' => '//div[@class="compact-link"]/a[contains(@href, "admin/compact/on") and text()="Hide descriptions"]',
+      ),
+      array(
+        'name' => "#type 'system_compact_link' when adding extra attributes",
+        'value' => array(
+          '#type' => 'system_compact_link',
+          '#attributes' => array(
+            'class' => array('kittens-rule'),
+          ),
+         ),
+        'expected' => '//div[@class="compact-link"]/a[contains(@href, "admin/compact/on") and @class="kittens-rule" and text()="Hide descriptions"]',
+      ),
+    );
+
+    foreach($elements as $element) {
+      $xml = new \SimpleXMLElement(drupal_render($element['value']));
+      $result = $xml->xpath($element['expected']);
+      $this->assertTrue($result, '"' . $element['name'] . '" is rendered correctly by drupal_render().');
+    }
+
+    // Set admin compact mode on for additional tests.
+    \Drupal::request()->cookies->set('Drupal_visitor_admin_compact_mode', TRUE);
+
+    $element = array(
+      'name' => "#type 'system_compact_link' when admin compact mode is on",
+      'value' => array(
+        '#type' => 'system_compact_link',
+      ),
+      'expected' => '//div[@class="compact-link"]/a[contains(@href, "admin/compact/off") and text()="Show descriptions"]',
+    );
+
+    $xml = new \SimpleXMLElement(drupal_render($element['value']));
+    $result = $xml->xpath($element['expected']);
+    $this->assertTrue($result, '"' . $element['name'] . '" is rendered correctly by drupal_render().');
+  }
+
 }
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 57edc26..0fc5922 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -84,7 +84,7 @@ function template_preprocess_admin_block_content(&$variables) {
  */
 function template_preprocess_admin_page(&$variables) {
   $variables['system_compact_link'] = array(
-    '#theme' => 'system_compact_link',
+    '#type' => 'system_compact_link',
   );
   $variables['containers'] = array();
   $stripe = 0;
@@ -113,7 +113,7 @@ function template_preprocess_admin_page(&$variables) {
  */
 function template_preprocess_system_admin_index(&$variables) {
   $variables['system_compact_link'] = array(
-    '#theme' => 'system_compact_link',
+    '#type' => 'system_compact_link',
   );
   $variables['containers'] = array();
   $stripe = 0;
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index c863fdd..a5628bf 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -212,9 +212,6 @@ function system_theme() {
       'file' => 'system.admin.inc',
       'template' => 'system-admin-index',
     ),
-    'system_compact_link' => array(
-      'variables' => array(),
-    ),
   ));
 }
 
@@ -1168,24 +1165,6 @@ function system_time_zones($blank = NULL) {
 }
 
 /**
- * Returns HTML for a link to show or hide inline help descriptions.
- *
- * @ingroup themeable
- */
-function theme_system_compact_link() {
-  $output = '<div class="compact-link">';
-  if (system_admin_compact_mode()) {
-    $output .= l(t('Show descriptions'), 'admin/compact/off', array('attributes' => array('title' => t('Expand layout to include descriptions.')), 'query' => drupal_get_destination()));
-  }
-  else {
-    $output .= l(t('Hide descriptions'), 'admin/compact/on', array('attributes' => array('title' => t('Compress layout by hiding descriptions.')), 'query' => drupal_get_destination()));
-  }
-  $output .= '</div>';
-
-  return $output;
-}
-
-/**
  * Attempts to get a file using Guzzle HTTP client and to store it locally.
  *
  * @param string $url
diff --git a/core/modules/system/templates/field.html.twig b/core/modules/system/templates/field.html.twig
index d38b028..80f4d93 100644
--- a/core/modules/system/templates/field.html.twig
+++ b/core/modules/system/templates/field.html.twig
@@ -21,8 +21,9 @@
  * - title_attributes: HTML attributes for the title.
  * - label: The label for the field.
  * - content_attributes: HTML attributes for the content.
- * - items: List of all the field items.
- * - item_attributes: List of HTML attributes for each item.
+ * - items: List of all the field items. Each item contains:
+ *   - #attributes: List of HTML attributes for each item.
+ *   - content: The field item's content.
  *
  * @see template_preprocess_field()
  *
@@ -31,11 +32,11 @@
 #}
 <div{{ attributes }}>
   {% if not label_hidden %}
-    <div class="field-label{% if title_attributes.class %} {{ title_attributes.class }}{% endif %}"{{ title_attributes|without('class') }}>{{ label }}:&nbsp;</div>
+    <div{{ title_attributes.addClass('field-label') }}>{{ label }}:&nbsp;</div>
   {% endif %}
-  <div class="field-items"{{ content_attributes }}>
-    {% for delta, item in items %}
-      <div class="field-item"{{ item_attributes[delta] }}>{{ item }}</div>
+  <div{{ content_attributes.addClass('field-items') }}>
+    {% for item in items %}
+      <div{{ item['#attributes'].addClass('field-item') }}>{{ item.content }}</div>
     {% endfor %}
   </div>
 </div>
diff --git a/core/modules/user/src/Form/UserPermissionsForm.php b/core/modules/user/src/Form/UserPermissionsForm.php
index 3f89bb6..1a6643a 100644
--- a/core/modules/user/src/Form/UserPermissionsForm.php
+++ b/core/modules/user/src/Form/UserPermissionsForm.php
@@ -97,7 +97,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
     $hide_descriptions = system_admin_compact_mode();
 
     $form['system_compact_link'] = array(
-      '#theme' => 'system_compact_link',
+      '#type' => 'system_compact_link',
     );
 
     $form['permissions'] = array(
diff --git a/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig b/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
index 4c579ee..c08299e 100644
--- a/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
+++ b/core/themes/bartik/templates/field--taxonomy-term-reference.html.twig
@@ -9,20 +9,21 @@
  * - title_attributes: HTML attributes for the label.
  * - label: The label for the field.
  * - content_attributes: HTML attributes for the content.
- * - items: List of all the field items.
- * - item_attributes: List of HTML attributes for each item.
+ * - items: List of all the field items. Each item contains:
+ *   - #attributes: List of HTML attributes for each item.
+ *   - content: The field item's content.
  *
  * @see template_preprocess_field()
  * @see bartik_preprocess_field()
  */
 #}
-<div class="{{ attributes.class }} clearfix"{{ attributes|without('class') }}>
+<div{{ attributes.addClass('clearfix') }}>
   {% if not label_hidden %}
     <h3{{ title_attributes }}>{{ label }}: </h3>
   {% endif %}
-  <ul class="links field-items {{ content_attributes.class }}"{{ content_attributes|without('class') }}>
-    {% for delta, item in items %}
-      <li class="taxonomy-term-reference-{{ delta }}"{{ item_attributes[delta] }}>{{ item }}</li>
+  <ul{{ content_attributes.addClass('links', 'field-items') }}>
+    {% for item in items %}
+      <li{{ item['#attributes'] }}>{{ item.content }}</li>
     {% endfor %}
   </ul>
 </div>