In the following code:
use std::sync::Mutex; static KEPT: Mutex<Vec<Box<dyn std::any::Any + Send>>> = Mutex::new(Vec::new()); struct Q<T: 'static + Send>(Option<T>); impl<T: 'static + Send> Drop for Q<T> { fn drop(&mut self) { if let Some(t) = self.0.take() { KEPT.lock().unwrap().push(Box::new(t)); } } } fn main() { { let l = String::from("hello world, this is lengthy enough"); let mut q = Q(None); q.0 = Some(&l); } let _z = String::from("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"); let k = KEPT.lock().unwrap(); println!("{}", k[0].downcast_ref::<&'static String>().unwrap()); }
I expected to see this happen: program is not accepted
Instead, this happened: program compiles and prints XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX. With asan, the program volition collision alongside a AddressSanitizer: stack-use-after-scope
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Issue on current nightly, and stables at smallest downward to 1.85.0
Godbolt alongside asan: https://rust.godbolt.org/z/83MvfbKde
Godbolt without asan: https://rust.godbolt.org/z/GsGdqqMWe
