Array Of Syntax should represent the following code https://wiki.php.net/rfc/arrayof

Options.md

Option A)

Null content items break things.

foreach ($foos as $foo) {
    if (! $foo instanceof Face) {
        throw new Exception ('AAAGGGGGHHH!');
    }
}

Optin B)

Nulls are great.

foreach ($foos as $foo) {
    if (! is_null($foo) and ! $foo instanceof Face) {
        throw new Exception ('AAAGGGGGHHH!');
    }
}