016 catchall on bare return refused

// Test 355_016: FRONTEND_COMPILE_ERROR — `|?` under a bare-return dispatch refuses.
//
// A `-> T` callee returns a value, not a tagged union — and even where
// unions do exist, there is no catch-all spelling. The parser refuses
// the arm itself, before the callee's shape is consulted.

~pub tor mk { x: i64 } -> i64
~mk -> x + 1

~pub tor observe { name: string }
~proc observe|zig {
    _ = name;
}

~mk(x: 1)
|? |> observe(name: "huh")