rust/src/test/compile-fail/borrowck-bad-nested-calls-move.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

45 lines
1.1 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.
// Test that we detect nested calls that could free pointers evaluated
// for earlier arguments.
fn rewrite(v: &mut Box<uint>) -> uint {
*v = box 22;
**v
}
fn add(v: &uint, w: Box<uint>) -> uint {
*v + *w
}
fn implicit() {
let mut a = box 1;
// Note the danger here:
//
// the pointer for the first argument has already been
// evaluated, but it gets moved when evaluating the second
// argument!
add(
&*a,
a); //~ ERROR cannot move
}
fn explicit() {
let mut a = box 1;
add(
&*a,
a); //~ ERROR cannot move
}
fn main() {}