As described in #53714, we currently permit a small amount of async notation in 2015, but we can't extend that to the complete feature set (e.g., await keywords etc). This was done as part of a transitionary tactic (so people could move to Rust 2018) but by now that is not necessary. We should just prohibit async fn in Rust 2015 entirely at this point.
As described in #53714, we currently permit a small amount of
asyncnotation in 2015, but we can't extend that to the complete feature set (e.g., await keywords etc). This was done as part of a transitionary tactic (so people could move to Rust 2018) but by now that is not necessary. We should just prohibitasync fnin Rust 2015 entirely at this point.