Fatal error: Uncaught Error: Class "Drupal\views\Plugin\views\argument\ArgumentPluginBase" not found in /home/www/drupal8/test/core/modules/search/src/Plugin/views/argument/Search.php:18 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/search/src/Plugin/views/argument/Search.php on line 18