services: service_container: class: Symfony\Component\DependencyInjection\ContainerInterface public: true synthetic: true foo: class: Class1 public: true arguments: [!service { class: Class2, arguments: [!service { class: Class2 }] }] Psr\Container\ContainerInterface: alias: service_container public: false Symfony\Component\DependencyInjection\ContainerInterface: alias: service_container public: false