rust/src/test/run-pass/borrowck-mut-uniq.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

42 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.
extern crate debug;
use std::mem::swap;
struct Ints {sum: Box<int>, values: Vec<int> }
fn add_int(x: &mut Ints, v: int) {
*x.sum += v;
let mut values = Vec::new();
swap(&mut values, &mut x.values);
values.push(v);
swap(&mut values, &mut x.values);
}
fn iter_ints(x: &Ints, f: |x: &int| -> bool) -> bool {
let l = x.values.len();
range(0u, l).all(|i| f(x.values.get(i)))
}
pub fn main() {
let mut ints = box Ints {sum: box 0, values: Vec::new()};
add_int(&mut *ints, 22);
add_int(&mut *ints, 44);
iter_ints(&*ints, |i| {
println!("int = {}", *i);
true
});
println!("ints={:?}", ints);
}