1 // Ensure that you cannot use generic types to return a region outside
2 // of its bound. Here, in the `return_it()` fn, we call with() but
3 // with R bound to &isize from the return_it. Meanwhile, with()
4 // provides a value that is only good within its own stack frame. This
5 // used to successfully compile because we failed to account for the
6 // fact that fn(x: &isize) rebound the region &.
8 fn with<R, F>(f: F) -> R where F: FnOnce(&isize) -> R {
12 fn return_it<'a>() -> &'a isize {
14 //~^ ERROR lifetime may not live long enough
19 println!("foo={}", *x);