src/test/ui/nll/issue-30104.rs

// Copyright 2018 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.

// Regression test for #30104

// compile-pass

#![feature(nll)]

use std::ops::{Deref, DerefMut};

fn box_two_field(v: &mut Box<(i32, i32)>) {
    let _a = &mut v.0;
    let _b = &mut v.1;
}

fn box_destructure(v: &mut Box<(i32, i32)>) {
    let (ref mut _head, ref mut _tail) = **v;
}

struct Wrap<T>(T);

impl<T> Deref for Wrap<T> {
    type Target = T;
    fn deref(&self) -> &T {
        &self.0
    }
}

impl<T> DerefMut for Wrap<T> {
    fn deref_mut(&mut self) -> &mut T {
        &mut self.0
    }
}

fn smart_two_field(v: &mut Wrap<(i32, i32)>) {
    let _a = &mut v.0;
    let _b = &mut v.1;
}

fn smart_destructure(v: &mut Wrap<(i32, i32)>) {
    let (ref mut _head, ref mut _tail) = **v;
}

fn main() {}