diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/sort/SortPluginBase.php b/core/modules/views/lib/Drupal/views/Plugin/views/sort/SortPluginBase.php
index a7ae4ac..99e805d 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/sort/SortPluginBase.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/sort/SortPluginBase.php
@@ -139,7 +139,7 @@ public function showExposeButton(&$form, &$form_state) {
    * Simple validate handler
    */
   public function validateOptionsForm(&$form, &$form_state) {
-    $this->sort_validate($form, $form_state);
+    $this->sortValidate($form, $form_state);
     if (!empty($this->options['exposed'])) {
       $this->validateExposeForm($form, $form_state);
     }
@@ -171,7 +171,7 @@ function show_sort_form(&$form, &$form_state) {
     }
   }
 
-  function sort_validate(&$form, &$form_state) { }
+  public function sortValidate(&$form, &$form_state) { }
 
   function sort_submit(&$form, &$form_state) { }