_|_ (bottom) in an expression alt or if doesn't typecheck

[marijnh]

fn foo() -> int {
    ret alt true {
      true { 1 }
      false { fail; }
    };
}

... produces mismatched types: expected int but found () (types differ)

[brson]

This is working as intended, but it has caused confusion twice this week.

The alt doesn't typecheck because the second arm has no trailing expression. If it said false { fail } then the type of the second arm would be _|_ and it would work.

I think I agree though that this should work as written.