1error[E0277]: expected a `Fn<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}` 2 --> $DIR/unboxed-closures-unsafe-extern-fn.rs:20:21 3 | 4LL | let x = call_it(&square, 22); 5 | ------- ^^^^^^^ expected an `Fn<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}` 6 | | 7 | required by a bound introduced by this call 8 | 9 = help: the trait `for<'r> Fn<(&'r isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}` 10note: required by a bound in `call_it` 11 --> $DIR/unboxed-closures-unsafe-extern-fn.rs:9:15 12 | 13LL | fn call_it<F: Fn(&isize) -> isize>(_: &F, _: isize) -> isize { 14 | ^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it` 15 16error[E0277]: expected a `FnMut<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}` 17 --> $DIR/unboxed-closures-unsafe-extern-fn.rs:25:25 18 | 19LL | let y = call_it_mut(&mut square, 22); 20 | ----------- ^^^^^^^^^^^ expected an `FnMut<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}` 21 | | 22 | required by a bound introduced by this call 23 | 24 = help: the trait `for<'r> FnMut<(&'r isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}` 25note: required by a bound in `call_it_mut` 26 --> $DIR/unboxed-closures-unsafe-extern-fn.rs:12:19 27 | 28LL | fn call_it_mut<F: FnMut(&isize) -> isize>(_: &mut F, _: isize) -> isize { 29 | ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it_mut` 30 31error[E0277]: expected a `FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}` 32 --> $DIR/unboxed-closures-unsafe-extern-fn.rs:30:26 33 | 34LL | let z = call_it_once(square, 22); 35 | ------------ ^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}` 36 | | 37 | required by a bound introduced by this call 38 | 39 = help: the trait `for<'r> FnOnce<(&'r isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}` 40note: required by a bound in `call_it_once` 41 --> $DIR/unboxed-closures-unsafe-extern-fn.rs:15:20 42 | 43LL | fn call_it_once<F: FnOnce(&isize) -> isize>(_: F, _: isize) -> isize { 44 | ^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `call_it_once` 45 46error: aborting due to 3 previous errors 47 48For more information about this error, try `rustc --explain E0277`. 49