So I just saw a tweet that shows a piece of code that uses .await today and I find that that .await part is not only barely visible, it is also completely indistinguishable from method calls. And this is from a code block that has syntax highlighting.
One of the impressions I have about Rust is that it forces you to explicitly perform operation that are expensive and/or time-consuming (for instance, you must explicitly call .clone() to clone an object, unlike C++). And in my opinion, that is a good thing.
Regarding await, while I do not consider it expensive, it can potentially be time-consuming (the program have to wait for the future). Having an await operator that is indistinguishable from field access might encourage programmer to write code that unnecessarily awaits independent futures sequentially:
get_future_1().await + get_future_2().await
while the correct (more performant) code should be:
let (a, b) = get_future_1().join(get_future_2()).await;
a + b
I don't know how can Rust make the "correct (more performant) code" easier to write and read, but I think Rust should make the "wrong code" more explicit by making await operator more visible. So that whenever I use await twice or more, the source code will scream to my face that "Hey, you have 2 awaits! Care to join them together?".
Ironically, this also rules out postfix sigil (one that I supported) as it is even more subtle than dot-await Actually, I take that back, because since I find ? postfix quite noticeable, I think @ postfix must be visible as well