composer update

vendor/symfony/routing/Loader/AnnotationFileLoader.php

@@ -46,7 +46,7 @@ class AnnotationFileLoader extends FileLoader
      * @param string      $file A PHP file path
      * @param string|null $type The resource type
      *
-     * @return RouteCollection A RouteCollection instance
+     * @return RouteCollection|null A RouteCollection instance
      *
      * @throws \InvalidArgumentException When the file does not exist or its routes cannot be parsed
      */
@@ -58,7 +58,7 @@ class AnnotationFileLoader extends FileLoader
         if ($class = $this->findClass($path)) {
             $refl = new \ReflectionClass($class);
             if ($refl->isAbstract()) {
-                return;
+                return null;
             }
 
             $collection->addResource(new FileResource($path));