39 lines
1.3 KiB
Rust
39 lines
1.3 KiB
Rust
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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Test that a type which is contravariant with respect to its region
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// parameter yields an error when used in a covariant way.
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//
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// Note: see variance-regions-*.rs for the tests that check that the
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// variance inference works in the first place.
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// This is covariant with respect to 'a, meaning that
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// Covariant<'foo> <: Covariant<'static> because
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// 'foo <= 'static
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struct Covariant<'a> {
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f: extern "Rust" fn(&'a int)
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}
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fn use_<'a>(c: Covariant<'a>) {
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let x = 3;
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// 'b winds up being inferred to 'a because
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// Covariant<'a> <: Covariant<'b> => 'a <= 'b
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//
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// Borrow checker then reports an error because `x` does not
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// have the lifetime 'a.
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collapse(&x, c); //~ ERROR borrowed value does not live long enough
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fn collapse<'b>(x: &'b int, c: Covariant<'b>) { }
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}
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fn main() {}
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