| // Copyright 2012 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // Tests that callees correctly infer an ordering between free regions |
| // that appear in their parameter list. See also |
| // regions-free-region-ordering-caller.rs |
| |
| fn ordering1<'a, 'b>(x: &'a &'b usize) -> &'a usize { |
| // It is safe to assume that 'a <= 'b due to the type of x |
| let y: &'b usize = &**x; |
| return y; |
| } |
| |
| fn ordering2<'a, 'b>(x: &'a &'b usize, y: &'a usize) -> &'b usize { |
| // However, it is not safe to assume that 'b <= 'a |
| &*y //~ ERROR cannot infer |
| } |
| |
| fn ordering3<'a, 'b>(x: &'a usize, y: &'b usize) -> &'a &'b usize { |
| // Do not infer an ordering from the return value. |
| let z: &'b usize = &*x; |
| //~^ ERROR cannot infer |
| panic!(); |
| } |
| |
| // see regions-free-region-ordering-callee-4.rs |
| |
| fn ordering5<'a, 'b>(a: &'a usize, b: &'b usize, x: Option<&'a &'b usize>) { |
| let z: Option<&'a &'b usize> = None; |
| } |
| |
| fn main() {} |