rust/src/test/compile-fail/borrowck-uniq-via-lend.rs
Patrick Walton de70d76373 librustc: Remove cross-borrowing of Box<T> to &T from the language,
except where trait objects are involved.

Part of issue #15349, though I'm leaving it open for trait objects.
Cross borrowing for trait objects remains because it is needed until we
have DST.

This will break code like:

    fn foo(x: &int) { ... }

    let a = box 3i;
    foo(a);

Change this code to:

    fn foo(x: &int) { ... }

    let a = box 3i;
    foo(&*a);

[breaking-change]
2014-07-17 14:05:36 -07:00

62 lines
1.3 KiB
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.
fn borrow(_v: &int) {}
fn local() {
let mut v = box 3i;
borrow(&*v);
}
fn local_rec() {
struct F { f: Box<int> }
let mut v = F {f: box 3};
borrow(&*v.f);
}
fn local_recs() {
struct F { f: G }
struct G { g: H }
struct H { h: Box<int> }
let mut v = F {f: G {g: H {h: box 3}}};
borrow(&*v.f.g.h);
}
fn aliased_imm() {
let mut v = box 3i;
let _w = &v;
borrow(&*v);
}
fn aliased_mut() {
let mut v = box 3i;
let _w = &mut v;
borrow(&*v); //~ ERROR cannot borrow `*v`
}
fn aliased_other() {
let mut v = box 3i;
let mut w = box 4i;
let _x = &mut w;
borrow(&*v);
}
fn aliased_other_reassign() {
let mut v = box 3i;
let mut w = box 4i;
let mut _x = &mut w;
_x = &mut v;
borrow(&*v); //~ ERROR cannot borrow `*v`
}
fn main() {
}