feature #42471 Add generic types to traversable implementations (derrabus)

This PR was merged into the 5.4 branch.

Discussion
----------

Add generic types to traversable implementations

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | no
| New feature?  | kinda
| Deprecations? | no
| Tickets       | N/A
| License       | MIT
| Doc PR        | N/A

Since tool support for generic types is growing, I wanted to give it a try and add generics to our traversable implementations. This should help Psalm to understand our code better. Furthermore, it helps app developers with running static code analysis on their own codebases.

Marking this as WIP for now until I reviewed all errors reported by Psalm.

Commits
-------

7f824fcf95 Add generic types to traversable implementations

Author: fabpot

Firewall.php

@@ -12,9 +12,11 @@
 namespace Symfony\Component\Security\Http;
 
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpKernel\Event\FinishRequestEvent;
 use Symfony\Component\HttpKernel\Event\RequestEvent;
 use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\Security\Http\Firewall\ExceptionListener;
 use Symfony\Component\Security\Http\Firewall\FirewallListenerInterface;
 use Symfony\Contracts\EventDispatcher\EventDispatcherInterface;
 
@@ -32,6 +34,10 @@ class Firewall implements EventSubscriberInterface
 {
     private $map;
     private $dispatcher;
+
+    /**
+     * @var \SplObjectStorage<Request, ExceptionListener>
+     */
     private $exceptionListeners;
 
     public function __construct(FirewallMapInterface $map, EventDispatcherInterface $dispatcher)

Firewall/ContextListener.php

@@ -58,7 +58,7 @@ class ContextListener extends AbstractListener
     private $sessionTrackerEnabler;
 
     /**
-     * @param iterable|UserProviderInterface[] $userProviders
+     * @param iterable<int, UserProviderInterface> $userProviders
      */
     public function __construct(TokenStorageInterface $tokenStorage, iterable $userProviders, string $contextKey, LoggerInterface $logger = null, EventDispatcherInterface $dispatcher = null, AuthenticationTrustResolverInterface $trustResolver = null, callable $sessionTrackerEnabler = null)
     {

FirewallMapInterface.php

@@ -12,6 +12,8 @@
 namespace Symfony\Component\Security\Http;
 
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Security\Http\Firewall\ExceptionListener;
+use Symfony\Component\Security\Http\Firewall\LogoutListener;
 
 /**
  * This interface must be implemented by firewall maps.
@@ -33,7 +35,7 @@ interface FirewallMapInterface
      * If there is no logout listener, the third element of the outer array
      * must be null.
      *
-     * @return array of the format [[AuthenticationListener], ExceptionListener, LogoutListener]
+     * @return array{list<callable>, ExceptionListener, LogoutListener}
      */
     public function getListeners(Request $request);
 }