diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/query/QueryPluginBase.php b/core/modules/views/lib/Drupal/views/Plugin/views/query/QueryPluginBase.php
index e78516d..ca6cfdb 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/query/QueryPluginBase.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/query/QueryPluginBase.php
@@ -79,12 +79,12 @@ function execute(ViewExecutable $view) {  }
    * @param view $view
    *   The view which is executed.
    */
-  function add_signature(ViewExecutable $view) { }
+  public function addSignature(ViewExecutable $view) { }
 
   /**
    * Get aggregation info for group by queries.
    *
-   * If NULL, aggregation is not allowed.
+   * If NULL, aggregation is not allowed.
    */
   function get_aggregation_info() { }
 
diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/query/Sql.php b/core/modules/views/lib/Drupal/views/Plugin/views/query/Sql.php
index 3f7c8bd..64b3aa7 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/query/Sql.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/query/Sql.php
@@ -1643,7 +1643,7 @@ function load_entities(&$results) {
     }
   }
 
-  function add_signature(ViewExecutable $view) {
+  public function addSignature(ViewExecutable $view) {
     $view->query->add_field(NULL, "'" . $view->storage->id() . ':' . $view->current_display . "'", 'view_name');
   }
 
diff --git a/core/modules/views/lib/Drupal/views/ViewExecutable.php b/core/modules/views/lib/Drupal/views/ViewExecutable.php
index a8a8dd2..6b462d0 100644
--- a/core/modules/views/lib/Drupal/views/ViewExecutable.php
+++ b/core/modules/views/lib/Drupal/views/ViewExecutable.php
@@ -1097,7 +1097,7 @@ public function build($display_id = NULL) {
     }
 
     if (config('views.settings')->get('sql_signature')) {
-      $this->query->add_signature($this);
+      $this->query->addSignature($this);
     }
 
     // Let modules modify the query just prior to finalizing it.