Referring specifically to this comment:

Unable to auto wire argument of type "Symfony\Component\Translation\TranslatorInterface" for the service X

@dunglas wrote:

Vendor classes must be fixed in the vendor or their definition must be overrided in your app.

We updated core classes of Symfony and “officials” bundles but it looks like we missed some components like Translator. Can you open a PR or open a bug in Symfony for this one?

So here's a BUG for that! Can I please type hint for this TranslatorInterface and be able to get an instance of "@translator.default" injected?