Error code E0727

A yield clause was used in an async context.

Erroneous code example:

#![feature(coroutines, stmt_expr_attributes)] fn main() { let coroutine = #[coroutine] || { async { yield; } }; }

Here, the yield keyword is used in an async block, which is not yet supported.

To fix this error, you have to move yield out of the async block:

#![feature(coroutines, stmt_expr_attributes)] fn main() { let coroutine = #[coroutine] || { yield; }; }