EmailConstraint.php

<?php

namespace Drupal\Core\Validation\Plugin\Validation\Constraint;

use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Validation\Attribute\Constraint;
use Symfony\Component\Validator\Constraints\Email;
use Symfony\Component\Validator\Constraints\EmailValidator;

/**
 * Count constraint.
 *
 * Overrides the symfony constraint to use the strict setting.
 */
class EmailConstraint extends Email {
    
    /**
     * {@inheritdoc}
     */
    public function __construct(...$args) {
        $this->mode = static::VALIDATION_MODE_STRICT;
        parent::__construct(...$args);
    }
    
    /**
     * {@inheritdoc}
     */
    public function validatedBy() : string {
        return EmailValidator::class;
    }

}