Fatal error: Uncaught Error: Class "Drupal\Core\Render\Element\RenderElementBase" not found in /home/qcsvlel/www/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php:16 Stack trace: #0 {main} thrown in /home/qcsvlel/www/core/modules/contextual/src/Element/ContextualLinksPlaceholder.php on line 16