src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr

error[E0277]: expected a `std::ops::Fn<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:21:21
   |
LL | fn call_it<F: Fn(&isize) -> isize>(_: &F, _: isize) -> isize {
   |               ------------------- required by this bound in `call_it`
...
LL |     let x = call_it(&square, 22);
   |                     ^^^^^^^ expected an `Fn<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
   |
   = help: the trait `for<'r> std::ops::Fn<(&'r isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`

error[E0277]: expected a `std::ops::FnMut<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:26:25
   |
LL | fn call_it_mut<F: FnMut(&isize) -> isize>(_: &mut F, _: isize) -> isize {
   |                   ---------------------- required by this bound in `call_it_mut`
...
LL |     let y = call_it_mut(&mut square, 22);
   |                         ^^^^^^^^^^^ expected an `FnMut<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
   |
   = help: the trait `for<'r> std::ops::FnMut<(&'r isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`

error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:31:26
   |
LL | fn call_it_once<F: FnOnce(&isize) -> isize>(_: F, _: isize) -> isize {
   |                    ----------------------- required by this bound in `call_it_once`
...
LL |     let z = call_it_once(square, 22);
   |                          ^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
   |
   = help: the trait `for<'r> std::ops::FnOnce<(&'r isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0277`.