diff --git a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Adapter.php b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Adapter.php
index 7b7875ef806c7..eb2ee9daab7bb 100644
--- a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Adapter.php
+++ b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Adapter.php
@@ -22,9 +22,9 @@
  */
 class Adapter implements AdapterInterface
 {
-    private $config;
-    private $connection;
-    private $entryManager;
+    private array $config;
+    private ConnectionInterface $connection;
+    private EntryManagerInterface $entryManager;
 
     public function __construct(array $config = [])
     {
@@ -40,11 +40,7 @@ public function __construct(array $config = [])
      */
     public function getConnection(): ConnectionInterface
     {
-        if (null === $this->connection) {
-            $this->connection = new Connection($this->config);
-        }
-
-        return $this->connection;
+        return $this->connection ??= new Connection($this->config);
     }
 
     /**
@@ -52,11 +48,7 @@ public function getConnection(): ConnectionInterface
      */
     public function getEntryManager(): EntryManagerInterface
     {
-        if (null === $this->entryManager) {
-            $this->entryManager = new EntryManager($this->getConnection());
-        }
-
-        return $this->entryManager;
+        return $this->entryManager ??= new EntryManager($this->getConnection());
     }
 
     /**
diff --git a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Collection.php b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Collection.php
index 123d7f8516416..5feb7c0ec1049 100644
--- a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Collection.php
+++ b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Collection.php
@@ -20,9 +20,9 @@
  */
 class Collection implements CollectionInterface
 {
-    private $connection;
-    private $search;
-    private $entries;
+    private Connection $connection;
+    private Query $search;
+    private array $entries;
 
     public function __construct(Connection $connection, Query $search)
     {
@@ -35,11 +35,7 @@ public function __construct(Connection $connection, Query $search)
      */
     public function toArray(): array
     {
-        if (null === $this->entries) {
-            $this->entries = iterator_to_array($this->getIterator(), false);
-        }
-
-        return $this->entries;
+        return $this->entries ??= iterator_to_array($this->getIterator(), false);
     }
 
     public function count(): int
diff --git a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Connection.php b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Connection.php
index cbcaf3efb43e4..ff898f1ec876a 100644
--- a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Connection.php
+++ b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Connection.php
@@ -29,8 +29,7 @@ class Connection extends AbstractConnection
     private const LDAP_TIMEOUT = 0x55;
     private const LDAP_ALREADY_EXISTS = 0x44;
 
-    /** @var bool */
-    private $bound = false;
+    private bool $bound = false;
 
     /** @var resource */
     private $connection;
diff --git a/src/Symfony/Component/Ldap/Adapter/ExtLdap/EntryManager.php b/src/Symfony/Component/Ldap/Adapter/ExtLdap/EntryManager.php
index 6f0bdd4f61b74..2191e407e8107 100644
--- a/src/Symfony/Component/Ldap/Adapter/ExtLdap/EntryManager.php
+++ b/src/Symfony/Component/Ldap/Adapter/ExtLdap/EntryManager.php
@@ -23,7 +23,7 @@
  */
 class EntryManager implements EntryManagerInterface
 {
-    private $connection;
+    private Connection $connection;
 
     public function __construct(Connection $connection)
     {
diff --git a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php
index 5e8563e21acfa..f6d51a81e808c 100644
--- a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php
+++ b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php
@@ -26,15 +26,9 @@ class Query extends AbstractQuery
     public const PAGINATION_OID = '1.2.840.113556.1.4.319';
 
     /** @var resource[] */
-    private $results;
+    private array $results;
 
-    /** @var array */
-    private $serverctrls = [];
-
-    public function __construct(Connection $connection, string $dn, string $query, array $options = [])
-    {
-        parent::__construct($connection, $dn, $query, $options);
-    }
+    private array $serverctrls = [];
 
     public function __sleep(): array
     {
@@ -51,7 +45,7 @@ public function __destruct()
         $con = $this->connection->getResource();
         $this->connection = null;
 
-        if (null === $this->results) {
+        if (!isset($this->results)) {
             return;
         }
 
@@ -63,7 +57,7 @@ public function __destruct()
                 throw new LdapException('Could not free results: '.ldap_error($con));
             }
         }
-        $this->results = null;
+        unset($this->results);
     }
 
     /**
@@ -71,7 +65,7 @@ public function __destruct()
      */
     public function execute(): CollectionInterface
     {
-        if (null === $this->results) {
+        if (!isset($this->results)) {
             // If the connection is not bound, throw an exception. Users should use an explicit bind call first.
             if (!$this->connection->isBound()) {
                 throw new NotBoundException('Query execution is not possible without binding the connection first.');
@@ -108,7 +102,7 @@ public function execute(): CollectionInterface
             $cookie = '';
             do {
                 if ($pageControl) {
-                    $this->controlPagedResult($con, $pageSize, true, $cookie);
+                    $this->controlPagedResult($pageSize, true, $cookie);
                 }
                 $sizeLimit = $itemsLeft;
                 if ($pageSize > 0 && $sizeLimit >= $pageSize) {
@@ -135,7 +129,7 @@ public function execute(): CollectionInterface
                     break;
                 }
                 if ($pageControl) {
-                    $cookie = $this->controlPagedResultResponse($con, $search, $cookie);
+                    $cookie = $this->controlPagedResultResponse($con, $search);
                 }
             } while (null !== $cookie && '' !== $cookie);
 
@@ -178,7 +172,7 @@ public function getResources(): array
     private function resetPagination()
     {
         $con = $this->connection->getResource();
-        $this->controlPagedResult($con, 0, false, '');
+        $this->controlPagedResult(0, false, '');
         $this->serverctrls = [];
 
         // This is a workaround for a bit of a bug in the above invocation
@@ -205,10 +199,8 @@ private function resetPagination()
 
     /**
      * Sets LDAP pagination controls.
-     *
-     * @param resource $con
      */
-    private function controlPagedResult($con, int $pageSize, bool $critical, string $cookie): bool
+    private function controlPagedResult(int $pageSize, bool $critical, string $cookie): bool
     {
         $this->serverctrls = [
             [
@@ -230,7 +222,7 @@ private function controlPagedResult($con, int $pageSize, bool $critical, string
      * @param resource $con
      * @param resource $result
      */
-    private function controlPagedResultResponse($con, $result, string $cookie = ''): string
+    private function controlPagedResultResponse($con, $result): string
     {
         ldap_parse_result($con, $result, $errcode, $matcheddn, $errmsg, $referrals, $controls);
 
diff --git a/src/Symfony/Component/Ldap/Adapter/ExtLdap/UpdateOperation.php b/src/Symfony/Component/Ldap/Adapter/ExtLdap/UpdateOperation.php
index cb57c1d6296ea..c2be3d57d48fb 100644
--- a/src/Symfony/Component/Ldap/Adapter/ExtLdap/UpdateOperation.php
+++ b/src/Symfony/Component/Ldap/Adapter/ExtLdap/UpdateOperation.php
@@ -15,9 +15,9 @@
 
 class UpdateOperation
 {
-    private $operationType;
-    private $values;
-    private $attribute;
+    private int $operationType;
+    private ?array $values;
+    private string $attribute;
 
     private const VALID_OPERATION_TYPES = [
         \LDAP_MODIFY_BATCH_ADD,
diff --git a/src/Symfony/Component/Ldap/Entry.php b/src/Symfony/Component/Ldap/Entry.php
index af438d182d52e..b1a60635ba172 100644
--- a/src/Symfony/Component/Ldap/Entry.php
+++ b/src/Symfony/Component/Ldap/Entry.php
@@ -17,17 +17,17 @@
  */
 class Entry
 {
-    private $dn;
+    private string $dn;
 
     /**
      * @var array<string, array>
      */
-    private $attributes = [];
+    private array $attributes = [];
 
     /**
      * @var array<string, string>
      */
-    private $lowerMap = [];
+    private array $lowerMap = [];
 
     /**
      * @param array<string, array> $attributes
diff --git a/src/Symfony/Component/Ldap/Ldap.php b/src/Symfony/Component/Ldap/Ldap.php
index e3c6ace140f29..9c717ce11bacb 100644
--- a/src/Symfony/Component/Ldap/Ldap.php
+++ b/src/Symfony/Component/Ldap/Ldap.php
@@ -22,7 +22,7 @@
  */
 final class Ldap implements LdapInterface
 {
-    private $adapter;
+    private AdapterInterface $adapter;
 
     public function __construct(AdapterInterface $adapter)
     {
diff --git a/src/Symfony/Component/Ldap/Security/CheckLdapCredentialsListener.php b/src/Symfony/Component/Ldap/Security/CheckLdapCredentialsListener.php
index 99b965c4d05c0..1980e7726a493 100644
--- a/src/Symfony/Component/Ldap/Security/CheckLdapCredentialsListener.php
+++ b/src/Symfony/Component/Ldap/Security/CheckLdapCredentialsListener.php
@@ -28,7 +28,7 @@
  */
 class CheckLdapCredentialsListener implements EventSubscriberInterface
 {
-    private $ldapLocator;
+    private ContainerInterface $ldapLocator;
 
     public function __construct(ContainerInterface $ldapLocator)
     {
diff --git a/src/Symfony/Component/Ldap/Security/LdapAuthenticator.php b/src/Symfony/Component/Ldap/Security/LdapAuthenticator.php
index 4211d792b2574..00802a5004207 100644
--- a/src/Symfony/Component/Ldap/Security/LdapAuthenticator.php
+++ b/src/Symfony/Component/Ldap/Security/LdapAuthenticator.php
@@ -17,7 +17,6 @@
 use Symfony\Component\Security\Core\Exception\AuthenticationException;
 use Symfony\Component\Security\Http\Authenticator\AuthenticatorInterface;
 use Symfony\Component\Security\Http\Authenticator\Passport\Passport;
-use Symfony\Component\Security\Http\Authenticator\Passport\PassportInterface;
 
 /**
  * This class decorates internal authenticators to add the LDAP integration.
@@ -32,12 +31,12 @@
  */
 class LdapAuthenticator implements AuthenticatorInterface
 {
-    private $authenticator;
-    private $ldapServiceId;
-    private $dnString;
-    private $searchDn;
-    private $searchPassword;
-    private $queryString;
+    private AuthenticatorInterface $authenticator;
+    private string $ldapServiceId;
+    private string $dnString;
+    private string $searchDn;
+    private string $searchPassword;
+    private string $queryString;
 
     public function __construct(AuthenticatorInterface $authenticator, string $ldapServiceId, string $dnString = '{username}', string $searchDn = '', string $searchPassword = '', string $queryString = '')
     {
diff --git a/src/Symfony/Component/Ldap/Security/LdapBadge.php b/src/Symfony/Component/Ldap/Security/LdapBadge.php
index af18e9817819e..4f78a39f9d0ba 100644
--- a/src/Symfony/Component/Ldap/Security/LdapBadge.php
+++ b/src/Symfony/Component/Ldap/Security/LdapBadge.php
@@ -24,12 +24,12 @@
  */
 class LdapBadge implements BadgeInterface
 {
-    private $resolved = false;
-    private $ldapServiceId;
-    private $dnString;
-    private $searchDn;
-    private $searchPassword;
-    private $queryString;
+    private bool $resolved = false;
+    private string $ldapServiceId;
+    private string $dnString;
+    private string $searchDn;
+    private string $searchPassword;
+    private ?string $queryString;
 
     public function __construct(string $ldapServiceId, string $dnString = '{username}', string $searchDn = '', string $searchPassword = '', string $queryString = null)
     {
diff --git a/src/Symfony/Component/Ldap/Security/LdapUser.php b/src/Symfony/Component/Ldap/Security/LdapUser.php
index b29429bb023ba..c5f4e6a7f8901 100644
--- a/src/Symfony/Component/Ldap/Security/LdapUser.php
+++ b/src/Symfony/Component/Ldap/Security/LdapUser.php
@@ -23,11 +23,11 @@
  */
 class LdapUser implements UserInterface, PasswordAuthenticatedUserInterface, EquatableInterface
 {
-    private $entry;
-    private $username;
-    private $password;
-    private $roles;
-    private $extraFields;
+    private Entry $entry;
+    private string $username;
+    private ?string $password;
+    private array $roles;
+    private array $extraFields;
 
     public function __construct(Entry $entry, string $username, ?string $password, array $roles = [], array $extraFields = [])
     {
diff --git a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
index 022c11b5ea664..01e4505199cdc 100644
--- a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
+++ b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
@@ -32,15 +32,15 @@
  */
 class LdapUserProvider implements UserProviderInterface, PasswordUpgraderInterface
 {
-    private $ldap;
-    private $baseDn;
-    private $searchDn;
-    private $searchPassword;
-    private $defaultRoles;
-    private $uidKey;
-    private $defaultSearch;
-    private $passwordAttribute;
-    private $extraFields;
+    private LdapInterface $ldap;
+    private string $baseDn;
+    private ?string $searchDn;
+    private ?string $searchPassword;
+    private array $defaultRoles;
+    private ?string $uidKey;
+    private string $defaultSearch;
+    private ?string $passwordAttribute;
+    private array $extraFields;
 
     public function __construct(LdapInterface $ldap, string $baseDn, string $searchDn = null, string $searchPassword = null, array $defaultRoles = [], string $uidKey = null, string $filter = null, string $passwordAttribute = null, array $extraFields = [])
     {