diff --git a/core/tests/Drupal/BuildTests/Framework/DrupalMinkClient.php b/core/tests/Drupal/BuildTests/Framework/DrupalMinkClient.php
index ad61087976f..78627abc228 100644
--- a/core/tests/Drupal/BuildTests/Framework/DrupalMinkClient.php
+++ b/core/tests/Drupal/BuildTests/Framework/DrupalMinkClient.php
@@ -30,7 +30,7 @@ class DrupalMinkClient extends Client {
    * @param bool $followMetaRefresh
    *   (optional) Whether to follow meta redirects. Defaults to TRUE.
    */
-  public function followMetaRefresh($followMetaRefresh = TRUE) {
+  public function followMetaRefresh(bool $followMetaRefresh = TRUE) {
     $this->followMetaRefresh = $followMetaRefresh;
   }