Error code E0727
A yield clause was used in an async context.
Erroneous code example:
#![feature(generators)] fn main() { let generator = || { 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(generators)] fn main() { let generator = || { yield; }; }