1 error[E0631]: type mismatch in closure arguments
2 --> $DIR/unboxed-closures-vtable-mismatch.rs:16:24
4 LL | let f = to_fn_mut(|x: usize, y: isize| -> isize { (x as isize) + y });
5 | ----------------------------- found signature defined here
7 LL | let z = call_it(3, f);
8 | ------- ^ expected due to this
10 | required by a bound introduced by this call
12 = note: expected closure signature `fn(isize, _) -> _`
13 found closure signature `fn(usize, _) -> _`
14 note: required by a bound in `call_it`
15 --> $DIR/unboxed-closures-vtable-mismatch.rs:7:15
17 LL | fn call_it<F: FnMut(isize, isize) -> isize>(y: isize, mut f: F) -> isize {
18 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it`
20 error: aborting due to previous error
22 For more information about this error, try `rustc --explain E0631`.