Fatal error: Uncaught Error: Interface "Drupal\Component\Plugin\PluginInspectionInterface" not found in /home/www/drupal8/test/modules/webform/src/Plugin/WebformElementInterface.php:23
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/modules/webform/src/Plugin/WebformElementInterface.php on line 23