[k_bx]

I disagree. It should be a compiler warning, maybe a "clippy" one, in such cases.

Btw the problem of sync code blocking async code is very real and also needs to be resolved, adding explicit `.blocking` to every blocking call is just as bad as explicit .await at every line.

Also, I like Haskell approach of being able to introduce syntax extensions at a file-level, so that for code that'd benefit from explicit await – I'd rather let author have it explicit.