Fatal error: Uncaught Error: Class "Drupal\Core\Config\Entity\ConfigEntityBase" not found in /home/www/drupal8/test/core/modules/language/src/Entity/ConfigurableLanguage.php:49 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/language/src/Entity/ConfigurableLanguage.php on line 49