rector/config/set/unwrap-compat.php

<?php

declare (strict_types=1);
namespace RectorPrefix20210808;

use Rector\DeadCode\Rector\If_\UnwrapFutureCompatibleIfFunctionExistsRector;
use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
return static function (\Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator $containerConfigurator) : void {
    $services = $containerConfigurator->services();
    $services->set(\Rector\DeadCode\Rector\If_\UnwrapFutureCompatibleIfFunctionExistsRector::class);
};