| error[E0658]: gen blocks are experimental | |
| --> $DIR/async_gen_fn.rs:4:1 | |
| | | |
| LL | async gen fn foo() {} | |
| | ^^^^^^^^^ | |
| | | |
| = note: see issue #117078 <https://github.com/rust-lang/rust/issues/117078> for more information | |
| = help: add `#![feature(gen_blocks)]` to the crate attributes to enable | |
| = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date | |
| error: aborting due to 1 previous error | |
| For more information about this error, try `rustc --explain E0658`. |