Fatal error: Uncaught Error: Interface "Drupal\Component\Discovery\DiscoverableInterface" not found in /home/www/drupal8/test/core/lib/Drupal/Component/Discovery/YamlDirectoryDiscovery.php:13 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Component/Discovery/YamlDirectoryDiscovery.php on line 13