When using a method of a service as configurator, the PhpDumper expects this service to be available through ->get(). This means we cannot use a private service here as the optimization would try to inline it (and even drop it entirely as it does not check configurators).

The easiest fix is probably to change the optimization pass to check configurators and force keeping services, as the XmlLoader does not support inline services for the configurator.

/cc @schmittjoh