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#![feature(coroutines, coroutine_trait, stmt_expr_attributes)]
use std::ops::{Coroutine, CoroutineState};
use std::pin::Pin;
struct SetToNone<'a: 'b, 'b>(&'b mut Option<&'a i32>);
impl<'a, 'b> Drop for SetToNone<'a, 'b> {
fn drop(&mut self) {
*self.0 = None;
}
}
fn drop_using_coroutine() -> i32 {
let mut y = Some(&0);
let z = &mut y;
let r;
{
let mut g = #[coroutine]
move |r| {
let _s = SetToNone(r);
yield;
};
let mut g = Pin::new(&mut g);
g.as_mut().resume(z);
r = y.as_ref().unwrap();
//~^ ERROR cannot borrow `y` as immutable because it is also borrowed as mutable
}
**r
}
fn main() {
println!("{}", drop_using_coroutine());
}
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