rust/src/test/compile-fail/regions-free-region-ordering-callee.rs
2013-11-26 08:19:00 -08:00

38 lines
1.3 KiB
Rust

// 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 uint) -> &'a uint {
// It is safe to assume that 'a <= 'b due to the type of x
let y: &'b uint = &**x;
return y;
}
fn ordering2<'a, 'b>(x: &'a &'b uint, y: &'a uint) -> &'b uint {
// However, it is not safe to assume that 'b <= 'a
&*y //~ ERROR cannot infer an appropriate lifetime
}
fn ordering3<'a, 'b>(x: &'a uint, y: &'b uint) -> &'a &'b uint {
// Do not infer an ordering from the return value.
let z: &'b uint = &*x;
//~^ ERROR cannot infer an appropriate lifetime
fail!();
}
fn ordering4<'a, 'b>(a: &'a uint, b: &'b uint, x: |&'a &'b uint|) {
let z: Option<&'a &'b uint> = None;
}
fn main() {}