sub ULONG ()  { 9 }
sub ENUM ()   { 23 }

my @annotations = (
    [ "id",     [ ULONG, "value", undef ] ],
    [ "autoid", [ ENUM, "AutoidKind", [ "SEQUENTIAL", "HASH" ] ],
                [ 'fixme', "value", "HASH" ] ]
  );
$annotations[1][2][0] = $annotations[1][1];

use Data::Dump;
dd @annotations;

__END__

do {
  my $b = [
    "autoid",
    [23, "AutoidKind", ["SEQUENTIAL", "HASH"]],
    ['fix', "value", "HASH"],
  ];
  $b->[2][0] = $b->[1];
  (["id", [9, "value", undef]], $b);
}