5 // Here, `f` is a function that takes a pointer `x` and a function
6 // `g`, where `g` requires its argument `y` to be in the same region
8 // pretty-expanded FIXME #23616
10 fn has_same_region(f: Box<dyn for<'a> FnMut(&'a isize, Box<dyn FnMut(&'a isize)>)>) {
11 // `f` should be the type that `wants_same_region` wants, but
12 // right now the compiler complains that it isn't.
16 fn wants_same_region(_f: Box<dyn for<'b> FnMut(&'b isize, Box<dyn FnMut(&'b isize)>)>) {