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extern crate maybe_uninit;
use maybe_uninit::MaybeUninit;
use std::cell::Cell;
struct DecrementOnDrop<'a>(&'a Cell<usize>);
impl<'a> DecrementOnDrop<'a> {
pub fn new(ref_:&'a Cell<usize>) -> Self {
ref_.set(1);
DecrementOnDrop(ref_)
}
}
impl<'a> Clone for DecrementOnDrop<'a> {
fn clone(&self) -> Self {
self.0.set(self.0.get() + 1);
DecrementOnDrop(self.0)
}
}
impl<'a> Drop for DecrementOnDrop<'a>{
fn drop(&mut self) {
self.0.set(self.0.get() - 1);
}
}
#[test]
fn doesnt_drop(){
let count = Cell::new(0);
let arc = DecrementOnDrop::new(&count);
let maybe = MaybeUninit::new(arc.clone());
assert_eq!(count.get(), 2);
drop(maybe);
assert_eq!(count.get(), 2);
}
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