Fatal error: Uncaught Error: Class "Symfony\Component\Translation\Extractor\Visitor\AbstractVisitor" not found in D:\Apache24\www\huahai\back-end\vendor\symfony\translation\Extractor\Visitor\ConstraintVisitor.php:22 Stack trace: #0 {main} thrown in D:\Apache24\www\huahai\back-end\vendor\symfony\translation\Extractor\Visitor\ConstraintVisitor.php on line 22