Fatal error: Uncaught Error: Interface "Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface" not found in /home/www/drupal8/test/core/lib/Drupal/Core/DependencyInjection/Compiler/BackendCompilerPass.php:34 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Core/DependencyInjection/Compiler/BackendCompilerPass.php on line 34