017 metatype catchall refused

// ============================================================================
// Test 210_017: FRONTEND_COMPILE_ERROR — `|? Transition` refuses at parse.
//
// Complement to 210_011: the metatype-bound catch-all spelled on a tor
// with a single optional sibling refuses identically — the arm is judged
// by its spelling, not by what the declared outcome set happens to be.
// ============================================================================

~tor process { value: u32 }
| success u32
| ?warning string

~proc process|zig {
    return .{ .success = value };
}

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

~process(value: 42)
| success _ |> _
|? Transition _ |> observed(name: "unhandled")