33 lines
1.1 KiB
Rust
33 lines
1.1 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.
|
||
|
|
|
||
|
|
// Test that a type which is contravariant with respect to its region
|
||
|
|
// parameter compiles successfully when used in a contravariant way.
|
||
|
|
//
|
||
|
|
// Note: see compile-fail/variance-regions-*.rs for the tests that check that the
|
||
|
|
// variance inference works in the first place.
|
||
|
|
|
||
|
|
struct Contravariant<'a> {
|
||
|
|
f: &'a int
|
||
|
|
}
|
||
|
|
|
||
|
|
fn use_<'a>(c: Contravariant<'a>) {
|
||
|
|
let x = 3;
|
||
|
|
|
||
|
|
// 'b winds up being inferred to this call.
|
||
|
|
// Contravariant<'a> <: Contravariant<'call> is true
|
||
|
|
// if 'call <= 'a, which is true, so no error.
|
||
|
|
collapse(&x, c);
|
||
|
|
|
||
|
|
fn collapse<'b>(x: &'b int, c: Contravariant<'b>) { }
|
||
|
|
}
|
||
|
|
|
||
|
|
fn main() {}
|