//@ edition:2021 use std::rc::Rc; async fn foo(x: Option) { let Some(_) = x else { let r = Rc::new(()); bar().await }; } async fn bar() -> ! { panic!() } fn is_send(_: T) {} async fn foo2(x: Option) { let Some(_) = x else { bar2(Rc::new(())).await }; } async fn bar2(_: T) -> ! { panic!() } async fn foo3(x: Option) { let Some(_) = x else { (Rc::new(()), bar().await); return; }; } async fn foo4(x: Option) { let Some(_) = x else { let r = Rc::new(()); bar().await; println!("{:?}", r); return; }; } fn main() { is_send(foo(Some(true))); //~^ ERROR cannot be sent between threads safely is_send(foo2(Some(true))); //~^ ERROR cannot be sent between threads safely is_send(foo3(Some(true))); //~^ ERROR cannot be sent between threads safely is_send(foo4(Some(true))); //~^ ERROR cannot be sent between threads safely }