This fails now with a typed exception "X::Syntax::AddCategorial::MissingSeparator" (commit https://github.com/rakudo/rakudo/commit/e9ea2dc0c5).
I added a test to S06-operator-overloading/sub.t with commit https://github.com/perl6/roast/commit/d84f6bcbb3 I'm closing this ticket -- please reopen if there is something missing.
