44 lines
1.5 KiB
Rust
44 lines
1.5 KiB
Rust
// 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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// Tests that callees correctly infer an ordering between free regions
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// that appear in their parameter list. See also
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// regions-free-region-ordering-caller.rs
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fn ordering1<'a, 'b>(x: &'a &'b usize) -> &'a usize {
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// It is safe to assume that 'a <= 'b due to the type of x
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let y: &'b usize = &**x;
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return y;
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}
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fn ordering2<'a, 'b>(x: &'a &'b usize, y: &'a usize) -> &'b usize {
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// However, it is not safe to assume that 'b <= 'a
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&*y //~ ERROR cannot infer
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}
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fn ordering3<'a, 'b>(x: &'a usize, y: &'b usize) -> &'a &'b usize {
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// Do not infer an ordering from the return value.
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let z: &'b usize = &*x;
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//~^ ERROR cannot infer
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panic!();
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}
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fn ordering4<'a, 'b, F>(a: &'a usize, b: &'b usize, x: F) where F: FnOnce(&'a &'b usize) {
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// Do not infer ordering from closure argument types.
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let z: Option<&'a &'b usize> = None;
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//~^ ERROR reference has a longer lifetime than the data it references
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}
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fn ordering5<'a, 'b>(a: &'a usize, b: &'b usize, x: Option<&'a &'b usize>) {
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let z: Option<&'a &'b usize> = None;
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}
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fn main() {}
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