rust/tests/fail/rc_as_ptr.rs
2022-07-11 11:48:56 +00:00

21 lines
740 B
Rust

// This should fail even without validation
//@compile-flags: -Zmiri-disable-validation
use std::ptr;
use std::rc::{Rc, Weak};
/// Taken from the `Weak::as_ptr` doctest.
fn main() {
let strong = Rc::new(Box::new(42));
let weak = Rc::downgrade(&strong);
// Both point to the same object
assert!(ptr::eq(&*strong, Weak::as_ptr(&weak)));
// The strong here keeps it alive, so we can still access the object.
assert_eq!(42, **unsafe { &*Weak::as_ptr(&weak) });
drop(strong);
// But not any more. We can do Weak::as_raw(&weak), but accessing the pointer would lead to
// undefined behaviour.
assert_eq!(42, **unsafe { &*Weak::as_ptr(&weak) }); //~ ERROR: dereferenced after this allocation got freed
}