[steveklabnik]

~~It can't.~~ See below, it can!

I tend to find, personally, that this kind of thing doesn't interfere strongly with reviewing. I think this is because I have an extensive background in dynamically typed languages and ones with strong inference like Rust, so I'm more used to it, whereas people who don't come from said backgrounds prefer more explicitness. YMMV of course!

[Tohquai7]

It can.

-Z unstable-options -Zunpretty=hir,typed

    // source
    pub fn square(num: i32) -> i32 {
        num * num
    }

    // expanded
    use ::std::prelude::v1::*;
    extern crate std;
    pub fn square(num: i32)
     -> i32 ({ ((num as i32) * (num as i32) as i32) } as i32)

You can try on https://rust.godbolt.org/

[steveklabnik]

Oh dang! That's very cool, thank you!

[jonathanyc]

I don’t think it’s just “strong” inference that’s the problem; I find I have an easier time reading ML because the inference somehow feels more obvious. After thinking about it some more, I think it really is deref coercion that is the gotcha, especially with function chaining.

[steveklabnik]

By "strong" I really mean "type inference" over "type deduction", to be clear. But yeah, I could see that.