PrimitiveTypeConstraint.php

<?php

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

use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Validation\Attribute\Constraint;
use Symfony\Component\Validator\Constraint as SymfonyConstraint;

/**
 * Supports validating all primitive types.
 */
class PrimitiveTypeConstraint extends SymfonyConstraint {
    public $message = 'This value should be of the correct primitive type.';

}