rust/src/test/compile-fail/kindck-owned-trait-contains.rs
Niko Matsakis 2b67d88809 Rewrite the coercion code to be more readable, more sound, and to reborrow when
needed.

Regarding soundness: there was a subtle bug in how it was done before; see the
compile-fail test for an example.

Regarding reborrowing: reborrowing allows mut and const
slices/borrowed-pointers to be used with pure fns that expect immutable data.

r=brson
2013-01-28 10:01:59 -08:00

31 lines
1016 B
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.
trait repeat<A> { fn get() -> A; }
impl<A:Copy> @A: repeat<A> {
fn get() -> A { *self }
}
fn repeater<A:Copy>(v: @A) -> repeat<A> {
// Note: owned kind is not necessary as A appears in the trait type
v as repeat::<A> // No
}
fn main() {
// Error results because the type of is inferred to be
// repeat<&blk/int> where blk is the lifetime of the block below.
let y = { //~ ERROR reference is not valid
let x: &blk/int = &3;
repeater(@x)
};
assert 3 == *(y.get()); //~ ERROR reference is not valid
}