rust/src/test/run-pass/borrowck-scope-of-deref-issue-4666.rs

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// Copyright 2012-2013 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.
// Tests that the scope of the pointer returned from `get()` is
// limited to the deref operation itself, and does not infect the
// block as a whole.
// pretty-expanded FIXME #23616
struct Box {
x: usize
}
impl Box {
fn get(&self) -> &usize {
&self.x
}
fn set(&mut self, x: usize) {
self.x = x;
}
}
fn fun1() {
// in the past, borrow checker behaved differently when
// init and decl of `v` were distinct
let v;
let mut a_box = Box {x: 0};
a_box.set(22);
v = *a_box.get();
a_box.set(v+1);
assert_eq!(23, *a_box.get());
}
fn fun2() {
let mut a_box = Box {x: 0};
a_box.set(22);
let v = *a_box.get();
a_box.set(v+1);
assert_eq!(23, *a_box.get());
}
pub fn main() {
fun1();
fun2();
}