Ill-formed byte sequences should be validated about emailvalidator HOT 4 CLOSED

use Egulias\EmailValidator\EmailValidator;

$validator = new EmailValidator;

for ($i = 0; $i < 0x100; ++$i) {

    $c = utf8_chr($i);
    $email = $c .'[email protected]';

    if ($validator->isValid($email)) {

        if (preg_match('/\p{Cc}/u', $c)) {
            $number = strtoupper(dechex($i));
            $length = strlen($number);
            $number = str_repeat('0', 4 - $length).$number;
            echo 'U+'.$number.' ';
        }
    }
}

echo PHP_EOL;

function utf8_chr($code_point) {

    if ($code_point < 0 || 0x10FFFF < $code_point || (0xD800 <= $code_point && $code_point <= 0xDFFF)) {
        return '';
    }

    if ($code_point < 0x80) {
        $hex[0] = $code_point;
        $ret = chr($hex[0]);
    } else if ($code_point < 0x800) {
        $hex[0] = 0x1C0 | $code_point >> 6;
        $hex[1] = 0x80  | $code_point & 0x3F;
        $ret = chr($hex[0]).chr($hex[1]);
    } else if ($code_point < 0x10000) {
        $hex[0] = 0xE0 | $code_point >> 12;
        $hex[1] = 0x80 | $code_point >> 6 & 0x3F;
        $hex[2] = 0x80 | $code_point & 0x3F;
        $ret = chr($hex[0]).chr($hex[1]).chr($hex[2]);
    } else  {
        $hex[0] = 0xF0 | $code_point >> 18;
        $hex[1] = 0x80 | $code_point >> 12 & 0x3F;
        $hex[2] = 0x80 | $code_point >> 6 & 0x3F;
        $hex[3] = 0x80 | $code_point  & 0x3F;
        $ret = chr($hex[0]).chr($hex[1]).chr($hex[2]).chr($hex[3]);
    }

    return $ret;
}