Possible suggestion improvements on match_ref_pats

[llogiq]

Another example from Carboxyl:

        match &mut *current.borrow_mut() {
            &mut Some(ref mut trans) => action(trans),
            _ => panic!("there is no active transaction to register a callback"),
        }

Our lint suggests using match *&mut *current.borrow_mut() { .. } while actually match *current.borrow_mut() { .. } (and removing &mut in the arm) will suffice.

[oli-obk]

Orthogonal issue:

shouldn't it actually be current.borrow_mut().expect("there is no active transaction to register a callback") ?

[llogiq]

I'm not going to judge... 😄

One could lint match some_option { None => panic!(..), .. }, but unless this is the only non-empty arm, it'd look very opinionated.