Fatal error: Uncaught Error: Class "Drupal\Core\Cache\Context\UserCacheContextBase" not found in /home/www/drupal8/test/core/modules/node/src/Cache/NodeAccessGrantsCacheContext.php:21 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/node/src/Cache/NodeAccessGrantsCacheContext.php on line 21