Fatal error: Uncaught Error: Class "Drupal\search\Plugin\SearchPluginBase" not found in /home/www/drupal8/test/core/modules/search/src/Plugin/ConfigurableSearchPluginBase.php:11 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/search/src/Plugin/ConfigurableSearchPluginBase.php on line 11