Fatal error: Uncaught Error: Class "Drupal\Core\Render\Element\RenderElement" not found in /home/www/drupal8/test/core/modules/contextual/src/Element/ContextualLinks.php:14
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/contextual/src/Element/ContextualLinks.php on line 14