Fatal error: Uncaught Error: Class "Drupal\Component\DependencyInjection\Dumper\OptimizedPhpArrayDumper" not found in /home/www/drupal8/test/core/lib/Drupal/Component/DependencyInjection/Dumper/PhpArrayDumper.php:19 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Component/DependencyInjection/Dumper/PhpArrayDumper.php on line 19