Your example is not what the dbus crate does, in your case everything is related to T, it doesn't surprise!
In that crate the &*msg.interface().unwrap() magically become an &str !
In that crate the &*msg.interface().unwrap() magically become an &str !
For example, the standard library `String` type dereferences to `str` which you can then re-reference to `&str`.
ameliaquining awnsered my question and you modulated my opinion, that pattern is can be idiomatic when the principle of minimal surprises is respected.