It wouldn’t be as relevant, since passing a function or method instead of a closure is much easier in Rust - you can just name it, while Ruby requires you to use the method method.

So instead of .map(|res| res.unwrap()) you can do .map(Result::unwrap) and it’ll Just Work™.

I’m glad it doesnt.

Swift does, though using the dollar sign rather than underscores

I sincerely doubt Rust would ever add something like this.