diff --git a/src/Loader/FilesystemLoader.php b/src/Loader/FilesystemLoader.php
index c152dd3de..41ad6da3d 100644
--- a/src/Loader/FilesystemLoader.php
+++ b/src/Loader/FilesystemLoader.php
@@ -252,7 +252,7 @@ class FilesystemLoader implements LoaderInterface, ExistsLoaderInterface, Source
 
     private function normalizeName($name)
     {
-        return preg_replace('#/{2,}#', '/', str_replace('\\', '/', $name));
+        return preg_replace('#/{2,}#', '/', str_replace('\\', '/', (string) $name));
     }
 
     private function parseName($name, $default = self::MAIN_NAMESPACE)
diff --git a/tests/Loader/FilesystemTest.php b/tests/Loader/FilesystemTest.php
index 520d1e4e1..cc1b4d759 100644
--- a/tests/Loader/FilesystemTest.php
+++ b/tests/Loader/FilesystemTest.php
@@ -214,10 +214,8 @@ class FilesystemTest extends TestCase
 
     /**
      * @dataProvider getArrayInheritanceTests
-     *
-     * @param $templateName string Template name with array inheritance
      */
-    public function testArrayInheritance($templateName)
+    public function testArrayInheritance(string $templateName)
     {
         $loader = new FilesystemLoader([]);
         $loader->addPath(__DIR__.'/Fixtures/inheritance');