src/test/ui/mismatched_types/unboxed-closures-vtable-mismatch.stderr

   1 error[E0281]: type mismatch: `[closure@$DIR/unboxed-closures-vtable-mismatch.rs:22:23: 22:73]` implements the trait `std::ops::FnMut<(usize, isize)>`, but the trait `std::ops::FnMut<(isize, isize)>` is required
   2   --> $DIR/unboxed-closures-vtable-mismatch.rs:25:13
   3    |
   4 22 |     let f = to_fn_mut(|x: usize, y: isize| -> isize { (x as isize) + y });
   5    |                       -------------------------------------------------- implements `std::ops::FnMut<(usize, isize)>`
   6 ...
   7 25 |     let z = call_it(3, f);
   8    |             ^^^^^^^
   9    |             |
  10    |             requires `std::ops::FnMut<(isize, isize)>`
  11    |             expected isize, found usize
  12    |
  13    = note: required by `call_it`
  14
  15 error: aborting due to previous error(s)
  16