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#![feature(coroutine_trait)]
#![feature(coroutines)]
use std::ops::Coroutine;
struct Contravariant<'a>(fn(&'a ()));
struct Covariant<'a>(fn() -> &'a ());
fn bad1<'short, 'long: 'short>() -> impl Coroutine<Covariant<'short>> {
#[coroutine] |_: Covariant<'short>| {
let a: Covariant<'long> = yield ();
//~^ ERROR lifetime may not live long enough
}
}
fn bad2<'short, 'long: 'short>() -> impl Coroutine<Contravariant<'long>> {
#[coroutine] |_: Contravariant<'long>| {
let a: Contravariant<'short> = yield ();
//~^ ERROR lifetime may not live long enough
}
}
fn good1<'short, 'long: 'short>() -> impl Coroutine<Covariant<'long>> {
#[coroutine] |_: Covariant<'long>| {
let a: Covariant<'short> = yield ();
}
}
fn good2<'short, 'long: 'short>() -> impl Coroutine<Contravariant<'short>> {
#[coroutine] |_: Contravariant<'short>| {
let a: Contravariant<'long> = yield ();
}
}
fn main() {}
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