diff --git a/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php b/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php
index 20f68399571f9..b00cc52dcbb16 100644
--- a/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php
+++ b/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php
@@ -44,7 +44,7 @@ public function __construct(ManagerRegistry $registry, string $classOrAlias, str
     /**
      * {@inheritdoc}
      */
-    public function loadUserByUsername($username)
+    public function loadUserByUsername(string $username)
     {
         $repository = $this->getRepository();
         if (null !== $this->property) {
@@ -102,7 +102,7 @@ public function refreshUser(UserInterface $user)
     /**
      * {@inheritdoc}
      */
-    public function supportsClass($class)
+    public function supportsClass(string $class)
     {
         return $class === $this->getClass() || is_subclass_of($class, $this->getClass());
     }
diff --git a/src/Symfony/Bridge/Doctrine/composer.json b/src/Symfony/Bridge/Doctrine/composer.json
index 648a5190cb7ed..301cb7ff43d69 100644
--- a/src/Symfony/Bridge/Doctrine/composer.json
+++ b/src/Symfony/Bridge/Doctrine/composer.json
@@ -33,7 +33,7 @@
         "symfony/property-access": "^4.4|^5.0",
         "symfony/property-info": "^4.4|^5.0",
         "symfony/proxy-manager-bridge": "^4.4|^5.0",
-        "symfony/security-core": "^4.4|^5.0",
+        "symfony/security-core": "^5.0",
         "symfony/expression-language": "^4.4|^5.0",
         "symfony/validator": "^4.4|^5.0",
         "symfony/translation": "^4.4|^5.0",
@@ -49,7 +49,8 @@
         "phpunit/phpunit": "<5.4.3",
         "symfony/dependency-injection": "<4.4",
         "symfony/form": "<4.4",
-        "symfony/messenger": "<4.4"
+        "symfony/messenger": "<4.4",
+        "symfony/security-core": "<5"
     },
     "suggest": {
         "symfony/form": "",
diff --git a/src/Symfony/Component/Security/Core/User/ChainUserProvider.php b/src/Symfony/Component/Security/Core/User/ChainUserProvider.php
index 4106ad190afea..9e9e86797b14c 100644
--- a/src/Symfony/Component/Security/Core/User/ChainUserProvider.php
+++ b/src/Symfony/Component/Security/Core/User/ChainUserProvider.php
@@ -49,7 +49,7 @@ public function getProviders()
     /**
      * {@inheritdoc}
      */
-    public function loadUserByUsername($username)
+    public function loadUserByUsername(string $username)
     {
         foreach ($this->providers as $provider) {
             try {
@@ -94,7 +94,7 @@ public function refreshUser(UserInterface $user)
     /**
      * {@inheritdoc}
      */
-    public function supportsClass($class)
+    public function supportsClass(string $class)
     {
         foreach ($this->providers as $provider) {
             if ($provider->supportsClass($class)) {
diff --git a/src/Symfony/Component/Security/Core/User/InMemoryUserProvider.php b/src/Symfony/Component/Security/Core/User/InMemoryUserProvider.php
index a5ad3f10f59e6..94f28ad98a54f 100644
--- a/src/Symfony/Component/Security/Core/User/InMemoryUserProvider.php
+++ b/src/Symfony/Component/Security/Core/User/InMemoryUserProvider.php
@@ -61,7 +61,7 @@ public function createUser(UserInterface $user)
     /**
      * {@inheritdoc}
      */
-    public function loadUserByUsername($username)
+    public function loadUserByUsername(string $username)
     {
         $user = $this->getUser($username);
 
@@ -85,7 +85,7 @@ public function refreshUser(UserInterface $user)
     /**
      * {@inheritdoc}
      */
-    public function supportsClass($class)
+    public function supportsClass(string $class)
     {
         return 'Symfony\Component\Security\Core\User\User' === $class;
     }
@@ -99,7 +99,7 @@ public function supportsClass($class)
      *
      * @throws UsernameNotFoundException if user whose given username does not exist
      */
-    private function getUser($username)
+    private function getUser(string $username)
     {
         if (!isset($this->users[strtolower($username)])) {
             $ex = new UsernameNotFoundException(sprintf('Username "%s" does not exist.', $username));
diff --git a/src/Symfony/Component/Security/Core/User/LdapUserProvider.php b/src/Symfony/Component/Security/Core/User/LdapUserProvider.php
index e467b3c3e0407..4d45bf9585bca 100644
--- a/src/Symfony/Component/Security/Core/User/LdapUserProvider.php
+++ b/src/Symfony/Component/Security/Core/User/LdapUserProvider.php
@@ -60,7 +60,7 @@ public function __construct(LdapInterface $ldap, string $baseDn, string $searchD
     /**
      * {@inheritdoc}
      */
-    public function loadUserByUsername($username)
+    public function loadUserByUsername(string $username)
     {
         try {
             $this->ldap->bind($this->searchDn, $this->searchPassword);
@@ -109,7 +109,7 @@ public function refreshUser(UserInterface $user)
     /**
      * {@inheritdoc}
      */
-    public function supportsClass($class)
+    public function supportsClass(string $class)
     {
         return 'Symfony\Component\Security\Core\User\User' === $class;
     }
@@ -117,12 +117,9 @@ public function supportsClass($class)
     /**
      * Loads a user from an LDAP entry.
      *
-     * @param string $username
-     * @param Entry  $entry
-     *
      * @return User
      */
-    protected function loadUser($username, Entry $entry)
+    protected function loadUser(string $username, Entry $entry)
     {
         $password = null;
         $extraFields = [];
@@ -140,11 +137,8 @@ protected function loadUser($username, Entry $entry)
 
     /**
      * Fetches a required unique attribute value from an LDAP entry.
-     *
-     * @param Entry|null $entry
-     * @param string     $attribute
      */
-    private function getAttributeValue(Entry $entry, $attribute)
+    private function getAttributeValue(Entry $entry, string $attribute)
     {
         if (!$entry->hasAttribute($attribute)) {
             throw new InvalidArgumentException(sprintf('Missing attribute "%s" for user "%s".', $attribute, $entry->getDn()));
diff --git a/src/Symfony/Component/Security/Core/User/MissingUserProvider.php b/src/Symfony/Component/Security/Core/User/MissingUserProvider.php
index 9605cf3168ec3..8c10ad377661e 100644
--- a/src/Symfony/Component/Security/Core/User/MissingUserProvider.php
+++ b/src/Symfony/Component/Security/Core/User/MissingUserProvider.php
@@ -32,7 +32,7 @@ public function __construct(string $firewall)
     /**
      * {@inheritdoc}
      */
-    public function loadUserByUsername($username)
+    public function loadUserByUsername(string $username)
     {
         throw new \BadMethodCallException();
     }
@@ -48,7 +48,7 @@ public function refreshUser(UserInterface $user)
     /**
      * {@inheritdoc}
      */
-    public function supportsClass($class)
+    public function supportsClass(string $class)
     {
         throw new \BadMethodCallException();
     }
diff --git a/src/Symfony/Component/Security/Core/User/UserProviderInterface.php b/src/Symfony/Component/Security/Core/User/UserProviderInterface.php
index 3e5b287316a98..708a97f4be404 100644
--- a/src/Symfony/Component/Security/Core/User/UserProviderInterface.php
+++ b/src/Symfony/Component/Security/Core/User/UserProviderInterface.php
@@ -39,13 +39,11 @@ interface UserProviderInterface
      * This method must throw UsernameNotFoundException if the user is not
      * found.
      *
-     * @param string $username The username
-     *
      * @return UserInterface
      *
      * @throws UsernameNotFoundException if the user is not found
      */
-    public function loadUserByUsername($username);
+    public function loadUserByUsername(string $username);
 
     /**
      * Refreshes the user.
@@ -65,9 +63,7 @@ public function refreshUser(UserInterface $user);
     /**
      * Whether this provider supports the given user class.
      *
-     * @param string $class
-     *
      * @return bool
      */
-    public function supportsClass($class);
+    public function supportsClass(string $class);
 }