Fatal error: Uncaught Error: Class "Drupal\hal\Normalizer\FieldItemNormalizer" not found in /home/www/drupal8/test/core/modules/hal/src/Normalizer/EntityReferenceItemNormalizer.php:17 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/hal/src/Normalizer/EntityReferenceItemNormalizer.php on line 17