error[E0597]: borrowed value does not live long enough
  --> src/main.rs:21:63
   |
21 |             _ => format!("{} potions", player_potions).as_ref(),
   |                  -------------------------------------        ^ temporary value dropped here while still borrowed
   |                  |
   |                  temporary value created here
...
72 |     }
   |     - temporary value needs to live until here
   |
   = note: this error originates in a macro outside of the current crate