rust/src/test/compile-fail/borrowck-uniq-via-lend.rs
Felix S. Klock II 270f0eef73 Add : Box<_> or ::Box<_> type annotations to various places.
This is the kind of change that one is expected to need to make to
accommodate overloaded-`box`.

----

Note that this is not *all* of the changes necessary to accommodate
Issue 22181.  It is merely the subset of those cases where there was
already a let-binding in place that made it easy to add the necesasry
type ascription.

(For unnamed intermediate `Box` values, one must go down a different
route; `Box::new` is the option that maximizes portability, but has
potential inefficiency depending on whether the call is inlined.)

----

There is one place worth note, `run-pass/coerce-match.rs`, where I
used an ugly form of `Box<_>` type ascription where I would have
preferred to use `Box::new` to accommodate overloaded-`box`.  I
deliberately did not use `Box::new` here, because that is already done
in coerce-match-calls.rs.

----

Precursor for overloaded-`box` and placement-`in`; see Issue 22181.
2015-03-03 20:29:01 +01:00

63 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.
#![feature(box_syntax)]
fn borrow(_v: &isize) {}
fn local() {
let mut v: Box<_> = box 3;
borrow(&*v);
}
fn local_rec() {
struct F { f: Box<isize> }
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<isize> }
let mut v = F {f: G {g: H {h: box 3}}};
borrow(&*v.f.g.h);
}
fn aliased_imm() {
let mut v: Box<_> = box 3;
let _w = &v;
borrow(&*v);
}
fn aliased_mut() {
let mut v: Box<_> = box 3;
let _w = &mut v;
borrow(&*v); //~ ERROR cannot borrow `*v`
}
fn aliased_other() {
let mut v: Box<_> = box 3;
let mut w: Box<_> = box 4;
let _x = &mut w;
borrow(&*v);
}
fn aliased_other_reassign() {
let mut v: Box<_> = box 3;
let mut w: Box<_> = box 4;
let mut _x = &mut w;
_x = &mut v;
borrow(&*v); //~ ERROR cannot borrow `*v`
}
fn main() {
}