src/test/ui/issue-27060.rs

// 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.

#[repr(packed)]
pub struct Good {
    data: &'static u32,
    data2: [&'static u32; 2],
    aligned: [u8; 32],
}

#[repr(packed)]
pub struct JustArray {
    array: [u32]
}

#[deny(safe_packed_borrows)]
fn main() {
    let good = Good {
        data: &0,
        data2: [&0, &0],
        aligned: [0; 32]
    };

    unsafe {
        let _ = &good.data; // ok
        let _ = &good.data2[0]; // ok
    }

    let _ = &good.data; //~ ERROR borrow of packed field is unsafe
                        //~| hard error
    let _ = &good.data2[0]; //~ ERROR borrow of packed field is unsafe
                            //~| hard error
    let _ = &*good.data; // ok, behind a pointer
    let _ = &good.aligned; // ok, has align 1
    let _ = &good.aligned[2]; // ok, has align 1
}