rust/tests/ui/mut_mut.rs

// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// 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.

#![allow(unused, clippy::no_effect, clippy::unnecessary_operation)]
#![warn(clippy::mut_mut)]

fn fun(x: &mut &mut u32) -> bool {
    **x > 0
}

fn less_fun(x: *mut *mut u32) {
    let y = x;
}

macro_rules! mut_ptr {
    ($p:expr) => {
        &mut $p
    };
}

#[allow(unused_mut, unused_variables)]
fn main() {
    let mut x = &mut &mut 1u32;
    {
        let mut y = &mut x;
    }

    if fun(x) {
        let y: &mut &mut u32 = &mut &mut 2;
        **y + **x;
    }

    if fun(x) {
        let y: &mut &mut &mut u32 = &mut &mut &mut 2;
        ***y + **x;
    }

    let mut z = mut_ptr!(&mut 3u32);
}

fn issue939() {
    let array = [5, 6, 7, 8, 9];
    let mut args = array.iter().skip(2);
    for &arg in &mut args {
        println!("{}", arg);
    }

    let args = &mut args;
    for arg in args {
        println!(":{}", arg);
    }
}