Merge branch '4.2'

* 4.2: (27 commits)
  [VarExporter] dont call userland code with uninitialized objects
  Fix typos in doc blocks
  [Debug] ignore underscore vs backslash namespaces in DebugClassLoader
  [TwigBridge][Form] Prevent multiple rendering of form collection prototypes
  [FrameworkBundle] fix describing routes with no controllers
  [DI] move RegisterServiceSubscribersPass before DecoratorServicePass
  Update ValidationListener.php
  [Yaml] ensures that the mb_internal_encoding is reset to its initial value
  [Messenger] Restore message handlers laziness
  [WebLink] Fixed documentation link
  [Security] getTargetPath of TargetPathTrait must return string or null
  [Hackday][Serializer] Deserialization ignores argument type hint from phpdoc for array in constructor argument
  Optimize perf by replacing call_user_func with dynamic vars
  [Cache] Fix dsn parsing
  [Routing] fix dumping same-path routes with placeholders
  [WebProfilerBundle][TwigBundle] CSS fixes
  Add a docblock for FormFactoryInterface
  [Security] defer log message in guard authenticator
  [Validator] Added IBAN format for Vatican City State
  merge conflicts
  ...

Author: nicolas-grekas

Iterator/CustomFilterIterator.php

@@ -51,7 +51,7 @@ public function accept()
         $fileinfo = $this->current();
 
         foreach ($this->filters as $filter) {
-            if (false === \call_user_func($filter, $fileinfo)) {
+            if (false === $filter($fileinfo)) {
                 return false;
             }
         }

Iterator/SortableIterator.php

@@ -73,7 +73,7 @@ public function __construct(\Traversable $iterator, $sort, bool $reverseOrder =
         } elseif (self::SORT_BY_NONE === $sort) {
             $this->sort = $order;
         } elseif (\is_callable($sort)) {
-            $this->sort = $reverseOrder ? function ($a, $b) use ($sort) { return -\call_user_func($sort, $a, $b); } : $sort;
+            $this->sort = $reverseOrder ? function ($a, $b) use ($sort) { return -$sort($a, $b); } : $sort;
         } else {
             throw new \InvalidArgumentException('The SortableIterator takes a PHP callable or a valid built-in sort algorithm as an argument.');
         }