diff --git a/core/lib/Drupal/Core/Entity/EntityConstraintViolationList.php b/core/lib/Drupal/Core/Entity/EntityConstraintViolationList.php
index d20bdf4..81eda2b 100644
--- a/core/lib/Drupal/Core/Entity/EntityConstraintViolationList.php
+++ b/core/lib/Drupal/Core/Entity/EntityConstraintViolationList.php
@@ -75,7 +75,7 @@ public function filterByField($field_name) {
   /**
    * {@inheritdoc}
    */
-  public function filterByFields($field_names) {
+  public function filterByFields(array $field_names) {
     if (!isset($this->violationsByField)) {
       $this->groupViolationsbyField();
     }