diff --git a/composer.json b/composer.json
index 2623b8f..b3f9810 100644
--- a/composer.json
+++ b/composer.json
@@ -18,6 +18,7 @@
     },
     "require-dev": {
         "symfony/phpunit-bridge": "^5.4 || ^6.4 || ^7.0 || ^8.0",
+        "symfony/form": "^5.4 || ^6.4 || ^7.0 || ^8.0",
         "symfony/translation": "^5.4 || ^6.4 || ^7.0 || ^8.0",
         "symfony/validator": "^5.4 || ^6.4 || ^7.0 || ^8.0",
         "symfony/twig-bridge": "^5.4 || ^6.4 || ^7.0 || ^8.0",
diff --git a/src/Visitor/Php/Symfony/FormTrait.php b/src/Visitor/Php/Symfony/FormTrait.php
index 71015a2..dbbf834 100644
--- a/src/Visitor/Php/Symfony/FormTrait.php
+++ b/src/Visitor/Php/Symfony/FormTrait.php
@@ -70,7 +70,8 @@ protected function loadParentInterfaces(string $parentFqcn): array
         $loading[$parentFqcn] = true;
 
         try {
-            $filePath = $this->findClassFile($parentFqcn);
+            $reflector = new \ReflectionClass($parentFqcn);
+            $filePath = $reflector->getFileName();
 
             if (!$filePath || !file_exists($filePath)) {
                 unset($loading[$parentFqcn]);
@@ -111,17 +112,4 @@ protected function loadParentInterfaces(string $parentFqcn): array
 
         return $interfaces;
     }
-
-    private function findClassFile(string $fqcn): ?string
-    {
-        $autoloadFile = __DIR__.'/../../../../vendor/autoload.php';
-
-        if (!file_exists($autoloadFile)) {
-            return null;
-        }
-
-        $loader = require $autoloadFile;
-
-        return $loader->findFile($fqcn) ?: null;
-    }
 }
diff --git a/tests/Resources/Php/Symfony/ParentType.php b/tests/Resources/Php/Symfony/ParentType.php
index 46fdc86..8a794f1 100644
--- a/tests/Resources/Php/Symfony/ParentType.php
+++ b/tests/Resources/Php/Symfony/ParentType.php
@@ -2,7 +2,10 @@
 
 namespace Translation\Extractor\Tests\Resources\Php\Symfony;
 
-class ParentType implements FormTypeInterface
+use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\FormBuilderInterface;
+
+class ParentType extends AbstractType
 {
     public function buildForm(FormBuilderInterface $builder, array $options): void
     {