diff --git a/core/lib/Drupal/Core/Template/Attribute.php b/core/lib/Drupal/Core/Template/Attribute.php
index b219624..6a09519 100644
--- a/core/lib/Drupal/Core/Template/Attribute.php
+++ b/core/lib/Drupal/Core/Template/Attribute.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Template;
 
 use ArrayAccess;
+use ArrayIterator;
 use IteratorAggregate;
 
 /**
diff --git a/core/lib/Drupal/Core/Template/AttributeArray.php b/core/lib/Drupal/Core/Template/AttributeArray.php
index d4f8771..95c346a 100644
--- a/core/lib/Drupal/Core/Template/AttributeArray.php
+++ b/core/lib/Drupal/Core/Template/AttributeArray.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Template;
 
 use ArrayAccess;
+use ArrayIterator;
 use IteratorAggregate;
 
 /**