"implicit, semicolonless return" doesn't work if followed by an inner function

[bblum]

fn main() {
    x()
    fn x() -> () { () }
}

produces:

what.rs:3:4: 3:6 error: expected `;` or `}` after expression but found `fn`
what.rs:3     fn x() -> () { () }
              ^~

The workaround is easy - you just write ret x(); explicitly. But maybe it's possible that we not have to?

Knowing nothing about parsing, I'm not sure if this can be resolved unambiguously, but I figured I'd mention it.

[sanxiyn]

I think this is working as designed.

[bstrie]

@nikomatsakis uses this style frequently and thinks that an explicit return here is fine. I also think being explicit here jives with user expectations, so I'm closing for now.