d6bd8d8491
This change has two consequences: 1. It makes `Arc<T>` and `Rc<T>` covariant in `T`. 2. It causes the compiler to reject code that was unsound with respect to dropck. See compile-fail/issue-29106.rs for an example of code that no longer compiles. Because of this, this is a [breaking-change]. Fixes #29037. Fixes #29106.
33 lines
823 B
Rust
33 lines
823 B
Rust
// Copyright 2015 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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// This test ensures that each pointer type `P<X>` is covariant in `X`.
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use std::rc::Rc;
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use std::sync::Arc;
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fn a<'r>(x: Box<&'static str>) -> Box<&'r str> {
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x
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}
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fn b<'r, 'w>(x: &'w &'static str) -> &'w &'r str {
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x
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}
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fn c<'r>(x: Arc<&'static str>) -> Arc<&'r str> {
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x
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}
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fn d<'r>(x: Rc<&'static str>) -> Rc<&'r str> {
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x
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}
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fn main() {}
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