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two-phase-activation-sharing-interference.rs
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two-phase-activation-sharing-interference.rs
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// Copyright 2017 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.
// revisions: lxl nll
//[lxl]compile-flags: -Z borrowck=mir -Z two-phase-borrows
//[nll]compile-flags: -Z borrowck=mir -Z two-phase-borrows -Z nll
// This is an important corner case pointed out by Niko: one is
// allowed to initiate a shared borrow during a reservation, but it
// *must end* before the activation occurs.
//
// FIXME: for clarity, diagnostics for these cases might be better off
// if they specifically said "cannot activate mutable borrow of `x`"
#![allow(dead_code)]
fn read(_: &i32) { }
fn ok() {
let mut x = 3;
let y = &mut x;
{ let z = &x; read(z); }
*y += 1;
}
fn not_ok() {
let mut x = 3;
let y = &mut x;
let z = &x;
*y += 1;
//[lxl]~^ ERROR cannot borrow `x` as mutable because it is also borrowed as immutable
//[nll]~^^ ERROR cannot borrow `x` as mutable because it is also borrowed as immutable
read(z);
}
fn should_be_ok_with_nll() {
let mut x = 3;
let y = &mut x;
let z = &x;
read(z);
*y += 1;
//[lxl]~^ ERROR cannot borrow `x` as mutable because it is also borrowed as immutable
// (okay with nll today)
}
fn should_also_eventually_be_ok_with_nll() {
let mut x = 3;
let y = &mut x;
let _z = &x;
*y += 1;
//[lxl]~^ ERROR cannot borrow `x` as mutable because it is also borrowed as immutable
//[nll]~^^ ERROR cannot borrow `x` as mutable because it is also borrowed as immutable
}
fn main() { }