LL | f(x)
| ^
| |
- | expected &mut isize, found struct `std::boxed::Box`
+ | expected `&mut isize`, found struct `std::boxed::Box`
| help: consider mutably borrowing here: `&mut x`
|
- = note: expected type `&mut isize`
- found type `std::boxed::Box<{integer}>`
+ = note: expected mutable reference `&mut isize`
+ found struct `std::boxed::Box<{integer}>`
error: aborting due to previous error