ERROR Async fn ret_type should be impl Future

[larsnystrom]

I'm using rust-analyzer in VSCode. There is a warning sign in the bottom menu next to "rust-analyzer"

When clicking it, it will show a log like this:

2024-07-22T07:35:38.105101Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:35:38.106845Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:35:38.107398Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:35:38.237284Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:35:38.237445Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:35:38.316788Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:35:38.319393Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:35:38.319521Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:36:21.562535Z ERROR Async fn ret_type should be impl Future
2024-07-22T07:36:32.607253Z ERROR Async fn ret_type should be impl Future

I do not have a ret_type function in my codebase.

How can I fix this error message?

Also, I've noticed that all types are {unknown}, is this related to the above message?

[lnicola]

Do you get a tooltip if you hover on that warning sign?

[lnicola]

You might be missing rust-src.

[larsnystrom]

I've installed rust with rustup-init. Can I use it to install rust-src? I tried just doing apt install rust-src (it was not already installed) but that didn't change anything.

[lnicola]

Don't mix the Debian and rustup Rusts. I think we normally do rustup component add rust-src, not sure why that's not working in your case.

[larsnystrom]

The $RUSTUP_HOME directory was owned by root, so rustup component add rust-src didn't work (at first I thought it was a proxy issue, because it said it couldn't download the file, but it was rather that it couldn't write to the target dir). I fixed the permissions, did rustup component add rust-src and reloaded VSCode and now it works! Thank you for your help!