Merge branch '4.3' into 4.4

* 4.3:
  cs fix
  Fix return statements
  [TwigBridge] add missing dep
  Add false type to ChoiceListFactoryInterface::createView $label argument
  Update UPGRADE guide of 4.3 for EventDispatcher
  [SecurityBundle] display the correct class name on the deprecated notice

Author: nicolas-grekas

Loader/AnnotationFileLoader.php

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