chap4, 4.6 unpacking code sample failed to work

[woosley]

# same thing:
sub first-is-largest(@a) {
    my :($first, *@rest) := \(|@a); 
                                            ~~~~~~~~~~This line is not working in rakudo
    return $first >= all(@rest);
}

(17:06:38) woosley: rakudo: @A = 2, 3, 4; my :($f, *$o) := (|@A); say $f.perl
(17:06:41) p6eval: rakudo 549d2a: OUTPUT«===SORRY!===␤Malformed my at line 22, near ":($f, $o) "␤»