| // Ensure that you cannot use generic types to return a region outside |
| // of its bound. Here, in the `return_it()` fn, we call with() but |
| // with R bound to &isize from the return_it. Meanwhile, with() |
| // provides a value that is only good within its own stack frame. This |
| // used to successfully compile because we failed to account for the |
| // fact that fn(x: &isize) rebound the region &. |
| |
| fn with<R, F>(f: F) -> R where F: FnOnce(&isize) -> R { |
| f(&3) |
| } |
| |
| fn return_it<'a>() -> &'a isize { |
| with(|o| o) |
| //~^ ERROR cannot infer |
| } |
| |
| fn main() { |
| let x = return_it(); |
| println!("foo={}", *x); |
| } |
