diff --git a/core/modules/migrate/src/Plugin/migrate/id_map/NullIdMap.php b/core/modules/migrate/src/Plugin/migrate/id_map/NullIdMap.php
index 744985a..a13ee6c 100644
--- a/core/modules/migrate/src/Plugin/migrate/id_map/NullIdMap.php
+++ b/core/modules/migrate/src/Plugin/migrate/id_map/NullIdMap.php
@@ -93,7 +93,7 @@ public function saveMessage(array $source_id_values, $message, $level = Migratio
    * {@inheritdoc}
    */
   public function getMessageIterator(array $source_id_values = [], $level = NULL) {
-    return new ArrayIterator([]);
+    return new \ArrayIterator([]);
   }
 
   /**