Fatal error: Uncaught Error: Interface "Drupal\Core\Entity\ContentEntityStorageInterface" not found in /home/www/drupal8/test/core/modules/aggregator/src/FeedStorageInterface.php:10 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/aggregator/src/FeedStorageInterface.php on line 10