core/lib/Drupal/Core/Form/ConfigFormBase.php | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/core/lib/Drupal/Core/Form/ConfigFormBase.php b/core/lib/Drupal/Core/Form/ConfigFormBase.php
index c0e691a8fa..e76386c4f9 100644
--- a/core/lib/Drupal/Core/Form/ConfigFormBase.php
+++ b/core/lib/Drupal/Core/Form/ConfigFormBase.php
@@ -68,7 +68,8 @@ public function buildForm(array $form, FormStateInterface $form_state) {
    * {@inheritdoc}
    */
   public function validateForm(array &$form, FormStateInterface $form_state) {
-    if (!in_array(ValidatableConfigFormTrait::class, class_uses($this))) {
+    // @see \Drupal\Core\Form\ValidatableConfigFormTrait
+    if (!method_exists($this, 'mapFormValuesToConfig')) {
       return;
     }
 
@@ -144,7 +145,8 @@ public function validateForm(array &$form, FormStateInterface $form_state) {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
-    if (in_array(ValidatableConfigFormTrait::class, class_uses($this))) {
+    // @see \Drupal\Core\Form\ValidatableConfigFormTrait
+    if (method_exists($this, 'mapFormValuesToConfig')) {
       foreach ($this->getEditableConfigNames() as $config_name) {
         $config = $this->config($config_name);
         // @phpstan-ignore-next-line