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1 | // Copyright 2012 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | // Test that a type which is contravariant with respect to its region | |
12 | // parameter yields an error when used in a covariant way. | |
13 | // | |
14 | // Note: see variance-regions-*.rs for the tests that check that the | |
15 | // variance inference works in the first place. | |
16 | ||
17 | use std::marker; | |
18 | ||
19 | // This is contravariant with respect to 'a, meaning that | |
20 | // Contravariant<'foo> <: Contravariant<'static> because | |
21 | // 'foo <= 'static | |
22 | struct Contravariant<'a> { | |
85aaf69f | 23 | marker: marker::PhantomData<&'a()> |
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24 | } |
25 | ||
26 | fn use_<'short,'long>(c: Contravariant<'short>, | |
27 | s: &'short isize, | |
28 | l: &'long isize, | |
29 | _where:Option<&'short &'long ()>) { | |
30 | ||
31 | // Test whether Contravariant<'short> <: Contravariant<'long>. Since | |
32 | // 'short <= 'long, this would be true if the Contravariant type were | |
33 | // covariant with respect to its parameter 'a. | |
34 | ||
ea8adc8c | 35 | let _: Contravariant<'long> = c; //~ ERROR E0623 |
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36 | } |
37 | ||
38 | fn main() {} |