Merge branch '5.2' into 5.x

* 5.2:
  [CS] Replace easy occurences of ?: with ??

Author: derrabus

Session/Session.php

@@ -39,14 +39,14 @@ class Session implements SessionInterface, \IteratorAggregate, \Countable
 
     public function __construct(SessionStorageInterface $storage = null, AttributeBagInterface $attributes = null, FlashBagInterface $flashes = null, callable $usageReporter = null)
     {
-        $this->storage = $storage ?: new NativeSessionStorage();
+        $this->storage = $storage ?? new NativeSessionStorage();
         $this->usageReporter = $usageReporter;
 
-        $attributes = $attributes ?: new AttributeBag();
+        $attributes = $attributes ?? new AttributeBag();
         $this->attributeName = $attributes->getName();
         $this->registerBag($attributes);
 
-        $flashes = $flashes ?: new FlashBag();
+        $flashes = $flashes ?? new FlashBag();
         $this->flashName = $flashes->getName();
         $this->registerBag($flashes);
     }