Fatal error: Uncaught Error: Interface "Drupal\Core\Language\LanguageManagerInterface" not found in /home/www/drupal8/test/core/modules/language/src/ConfigurableLanguageManagerInterface.php:11 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/language/src/ConfigurableLanguageManagerInterface.php on line 11