Fatal error: Uncaught Error: Class "Drupal\Core\Controller\ControllerBase" not found in /home/www/drupal8/test/core/modules/block/src/Controller/BlockLibraryController.php:19
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/block/src/Controller/BlockLibraryController.php on line 19