Fatal error: Uncaught Error: Class "Drupal\Core\Entity\Plugin\Validation\Constraint\CompositeConstraintBase" not found in /home/www/drupal8/test/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php:16 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/comment/src/Plugin/Validation/Constraint/CommentNameConstraint.php on line 16