Format async block and async fn

[topecongiro]

E.g.

async unsafe fn foo() {
    async move {}
}
async fn bar() {}

[rfernbach]

I would be interested in tackling this.

[nrc]

Fixed by #2874

[autolyticus]

I'm unsure of whether to open a new issue or not. The latest stable version of rustfmt

rustfmt 1.4.8-stable (afb1ee1 2019-09-08)

fails to format this program

use async_std::task;

fn main() {
    task::block_on(async {
        println!("Hello, world!");
    })
}

With this error:

error: expected one of `,` or `}`, found `!`
 --> <stdin>:5:16
  |
4 |     task::block_on(async {
  |                    ----- while parsing this struct
5 |         println!("Hello, world!");
  |                ^ expected one of `,` or `}` here

The same is true for the latest nightly

rustfmt 1.4.9-nightly (33e3667 2019-10-07)

Am I doing something wrong?

[calebcartwright]

@reisub0 - are you using cargo fmt or running rustfmt directly?

If the latter, try including the edition flag --edition 2018

[autolyticus]

@calebcartwright - Thank you! Using the --edition flag worked. I was using rustfmt on <stdin> mode as part of a (Neo)Vim plugin and not cargo fmt. I expected the default edition to be the latest(2018). And I didn't find any other documentation on the README. But I guess it hasn't reached stable yet as that was only a recent change (#3942).

Thanks for your help and sorry for the bother.

[calebcartwright]

No worries @reisub0, happy to help! Also, if you ever have any future questions, another available option is the Discord channel for rustfmt (this can be especially useful if you're unsure whether to create a new issue)