1error[E0631]: type mismatch in closure arguments
2  --> $DIR/unboxed-closures-vtable-mismatch.rs:16:24
3   |
4LL |     let f = to_fn_mut(|x: usize, y: isize| -> isize { (x as isize) + y });
5   |                       ----------------------------- found signature of `fn(usize, isize) -> _`
6LL |
7LL |     let z = call_it(3, f);
8   |             -------    ^ expected signature of `fn(isize, isize) -> _`
9   |             |
10   |             required by a bound introduced by this call
11   |
12note: required by a bound in `call_it`
13  --> $DIR/unboxed-closures-vtable-mismatch.rs:7:14
14   |
15LL | fn call_it<F:FnMut(isize,isize)->isize>(y: isize, mut f: F) -> isize {
16   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it`
17
18error: aborting due to previous error
19
20For more information about this error, try `rustc --explain E0631`.
21