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