7 files declare their use of DiscoveryInterface in Service Container 7

AnnotatedClassDiscovery.php in lib/Drupal/Component/Annotation/Plugin/Discovery/AnnotatedClassDiscovery.php

Contains \Drupal\Component\Annotation\Plugin\Discovery\AnnotatedClassDiscovery.

AnnotatedClassDiscovery.php in modules/providers/service_container_annotation_discovery/src/Plugin/Discovery/AnnotatedClassDiscovery.php

Contains \Drupal\service_container_annotation_discovery\Plugin\Discovery\AnnotatedClassDiscovery

ContainerInterface.php in src/DependencyInjection/ContainerInterface.php

Contains \Drupal\service_container\DependencyInjection\ContainerInterface.

CToolsPluginDiscovery.php in src/Plugin/Discovery/CToolsPluginDiscovery.php

Contains \Drupal\service_container\Plugin\Discovery\CToolsPluginDiscovery

DefaultFactory.php in lib/Drupal/Component/Plugin/Factory/DefaultFactory.php

Contains \Drupal\Component\Plugin\Factory\DefaultFactory.

DefaultPluginManager.php in src/Plugin/DefaultPluginManager.php

Contains \Drupal\service_container\Plugin\DefaultPluginManager

PluginManagerInterface.php in lib/Drupal/Component/Plugin/PluginManagerInterface.php

Contains \Drupal\Component\Plugin\PluginManagerInterface.