Fatal error: Uncaught Error: Class "Drupal\Component\Plugin\Derivative\DeriverBase" not found in /home/www/drupal8/test/core/lib/Drupal/Core/Entity/Plugin/Derivative/DefaultSelectionDeriver.php:19 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Core/Entity/Plugin/Derivative/DefaultSelectionDeriver.php on line 19