Merge branch '4.4' into 5.2

* 4.4:
  Switched to non-null defaults in exception constructors
  [Routing] fix conflict with param named class in attribute
  [Cache] fix setting items' metadata on commit()

Author: nicolas-grekas

Routing/DelegatingLoader.php

@@ -61,7 +61,7 @@ public function load($resource, string $type = null)
             // - this handles the case and prevents the second fatal error
             //   by triggering an exception beforehand.
 
-            throw new LoaderLoadException($resource, null, null, null, $type);
+            throw new LoaderLoadException($resource, null, 0, null, $type);
         }
         $this->loading = true;