src/test/run-fail/issue-30380.rs

// Copyright 2016 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.

#![feature(rustc_attrs)]

// check that panics in destructors during assignment do not leave
// destroyed values lying around for other destructors to observe.

// error-pattern:panicking destructors ftw!

struct Observer<'a>(&'a mut FilledOnDrop);

struct FilledOnDrop(u32);
impl Drop for FilledOnDrop {
    fn drop(&mut self) {
        if self.0 == 0 {
            // this is only set during the destructor - safe
            // code should not be able to observe this.
            self.0 = 0x1c1c1c1c;
            panic!("panicking destructors ftw!");
        }
    }
}

impl<'a> Drop for Observer<'a> {
    fn drop(&mut self) {
        assert_eq!(self.0 .0, 1);
    }
}

#[rustc_mir]
fn foo(b: &mut Observer) {
    *b.0 = FilledOnDrop(1);
}

fn main() {
    let mut bomb = FilledOnDrop(0);
    let mut observer = Observer(&mut bomb);
    foo(&mut observer);
}