Fatal error: Uncaught Error: Class "Drupal\Core\Render\Element\RenderElement" not found in /home/www/drupal8/test/core/modules/toolbar/src/Element/ToolbarItem.php:15
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/modules/toolbar/src/Element/ToolbarItem.php on line 15