File: issue-90752-raw-ptr-shenanigans.rs

package info (click to toggle)
rustc 1.85.0%2Bdfsg3-1
  • links: PTS, VCS
  • area: main
  • in suites: experimental, sid, trixie
  • size: 893,396 kB
  • sloc: xml: 158,127; python: 35,830; javascript: 19,497; cpp: 19,002; sh: 17,245; ansic: 13,127; asm: 4,376; makefile: 1,051; perl: 29; lisp: 29; ruby: 19; sql: 11
file content (41 lines) | stat: -rw-r--r-- 833 bytes parent folder | download | duplicates (5)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
//@ run-pass

use std::cell::RefCell;

struct S<'a>(i32, &'a RefCell<Vec<i32>>);

impl<'a> Drop for S<'a> {
    fn drop(&mut self) {
        self.1.borrow_mut().push(self.0);
    }
}

fn test(drops: &RefCell<Vec<i32>>) {
    let mut foo = None;
    let pfoo: *mut _ = &mut foo;

    match foo {
        None => (),
        _ => return,
    }

    // Both S(0) and S(1) should be dropped, but aren't.
    unsafe { *pfoo = Some((S(0, drops), S(1, drops))); }

    match foo {
        Some((_x, _)) => {}
        _ => {}
    }
}

fn main() {
    let drops = RefCell::new(Vec::new());
    test(&drops);

    // Ideally, we want this...
    //assert_eq!(*drops.borrow(), &[0, 1]);

    // But the delayed access through the raw pointer confuses drop elaboration,
    // causing S(1) to be leaked.
    assert_eq!(*drops.borrow(), &[0]);
}