diff -u b/core/lib/Drupal/Core/Field/WidgetBase.php b/core/lib/Drupal/Core/Field/WidgetBase.php
--- b/core/lib/Drupal/Core/Field/WidgetBase.php
+++ b/core/lib/Drupal/Core/Field/WidgetBase.php
@@ -217,7 +217,7 @@
       // Add 'add more' button, if not working with a programmed form.
       if ($cardinality == FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED && !$form_state->isProgrammed()) {
         $id_prefix = implode('-', array_merge($parents, array($field_name)));
-        $wrapper_id = HTML::getUniqueId($id_prefix . '-add-more-wrapper');
+        $wrapper_id = Html::getUniqueId($id_prefix . '-add-more-wrapper');
         $elements['#prefix'] = '<div id="' . $wrapper_id . '">';
         $elements['#suffix'] = '</div>';
 
diff -u b/core/lib/Drupal/Core/Render/Element/Link.php b/core/lib/Drupal/Core/Render/Element/Link.php
--- b/core/lib/Drupal/Core/Render/Element/Link.php
+++ b/core/lib/Drupal/Core/Render/Element/Link.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Render\Element;
 
 use Drupal\Component\Utility\NestedArray;
+use Drupal\Component\Utility\Html;
 
 /**
  * Provides a link render element.
@@ -69,7 +70,7 @@
     if (isset($element['#ajax']) && !isset($element['#ajax_processed'])) {
       // If no HTML ID was found above, automatically create one.
       if (!isset($element['#id'])) {
-        $element['#id'] = $element['#options']['attributes']['id'] = \Drupal\Component\Utility\Html::getUniqueId('ajax-link');
+        $element['#id'] = $element['#options']['attributes']['id'] = Html::getUniqueId('ajax-link');
       }
       $element = static::preRenderAjaxForm($element);
     }
diff -u b/core/lib/Drupal/Core/Render/Element/Radios.php b/core/lib/Drupal/Core/Render/Element/Radios.php
--- b/core/lib/Drupal/Core/Render/Element/Radios.php
+++ b/core/lib/Drupal/Core/Render/Element/Radios.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Render\Element;
 
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Component\Utility\Html;
 
 /**
  * Provides a form element for a set of radio buttons.
@@ -65,7 +66,7 @@
           '#default_value' => isset($element['#default_value']) ? $element['#default_value'] : FALSE,
           '#attributes' => $element['#attributes'],
           '#parents' => $element['#parents'],
-          '#id' => \Drupal\Component\Utility\Html::getUniqueId('edit-' . implode('-', $parents_for_id)),
+          '#id' => Html::getUniqueId('edit-' . implode('-', $parents_for_id)),
           '#ajax' => isset($element['#ajax']) ? $element['#ajax'] : NULL,
           '#weight' => $weight,
         );
diff -u b/core/lib/Drupal/Core/Render/Element/Table.php b/core/lib/Drupal/Core/Render/Element/Table.php
--- b/core/lib/Drupal/Core/Render/Element/Table.php
+++ b/core/lib/Drupal/Core/Render/Element/Table.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Render\Element;
+use Drupal\Component\Utility\Html;
 
 /**
  * Provides a render element for a table.
@@ -134,7 +135,7 @@
         // an #id for the row element, since
         // \Drupal\Component\Utility\Html::getUniqueId() would automatically
         // append a suffix to the tableselect form element's #id otherwise.
-        $row['#id'] = \Drupal\Component\Utility\Html::getUniqueId('edit-' . implode('-', $element_parents) . '-row');
+        $row['#id'] = Html::getUniqueId('edit-' . implode('-', $element_parents) . '-row');
 
         // Do not overwrite manually created children.
         if (!isset($row['select'])) {
@@ -172,7 +173,7 @@
           $row = array('select' => array()) + $row;
           $row['select'] += array(
             '#type' => $element['#multiple'] ? 'checkbox' : 'radio',
-            '#id' => \Drupal\Component\Utility\Html::getUniqueId('edit-' . implode('-', $element_parents)),
+            '#id' => Html::getUniqueId('edit-' . implode('-', $element_parents)),
             // @todo If rows happen to use numeric indexes instead of string keys,
             //   this results in a first row with $key === 0, which is always FALSE.
             '#return_value' => $key,
diff -u b/core/lib/Drupal/Core/Render/Element/Tableselect.php b/core/lib/Drupal/Core/Render/Element/Tableselect.php
--- b/core/lib/Drupal/Core/Render/Element/Tableselect.php
+++ b/core/lib/Drupal/Core/Render/Element/Tableselect.php
@@ -9,6 +9,7 @@
 
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Render\Element;
+use Drupal\Component\Utility\Html;
 
 /**
  * Provides a form element for a table with radios or checkboxes in left column.
@@ -236,7 +237,7 @@
               '#default_value' => ($element['#default_value'] == $key) ? $key : NULL,
               '#attributes' => $element['#attributes'],
               '#parents' => $element['#parents'],
-              '#id' => \Drupal\Component\Utility\Html::getUniqueId('edit-' . implode('-', $parents_for_id)),
+              '#id' => Html::getUniqueId('edit-' . implode('-', $parents_for_id)),
               '#ajax' => isset($element['#ajax']) ? $element['#ajax'] : NULL,
             );
           }