diff --git a/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php b/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php
index 101c61f07882a..f8984bd627a09 100644
--- a/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php
+++ b/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php
@@ -133,7 +133,7 @@ public function format(array $record)
     /**
      * @internal
      */
-    public function echoLine($line, $depth, $indentPad)
+    public function echoLine(string $line, int $depth, string $indentPad)
     {
         if (-1 !== $depth) {
             fwrite($this->outputBuffer, $line);
@@ -143,7 +143,7 @@ public function echoLine($line, $depth, $indentPad)
     /**
      * @internal
      */
-    public function castObject($v, array $a, Stub $s, $isNested)
+    public function castObject($v, array $a, Stub $s, bool $isNested)
     {
         if ($this->options['multiline']) {
             return $a;
diff --git a/src/Symfony/Component/BrowserKit/CookieJar.php b/src/Symfony/Component/BrowserKit/CookieJar.php
index bc9b781bb2b7d..3a585bed668f3 100644
--- a/src/Symfony/Component/BrowserKit/CookieJar.php
+++ b/src/Symfony/Component/BrowserKit/CookieJar.php
@@ -106,9 +106,8 @@ public function clear()
      * Updates the cookie jar from a response Set-Cookie headers.
      *
      * @param string[] $setCookies Set-Cookie headers from an HTTP response
-     * @param string   $uri        The base URL
      */
-    public function updateFromSetCookie(array $setCookies, $uri = null)
+    public function updateFromSetCookie(array $setCookies, string $uri = null)
     {
         $cookies = [];
 
@@ -133,8 +132,6 @@ public function updateFromSetCookie(array $setCookies, $uri = null)
 
     /**
      * Updates the cookie jar from a Response object.
-     *
-     * @param string $uri The base URL
      */
     public function updateFromResponse(Response $response, string $uri = null)
     {
diff --git a/src/Symfony/Component/Config/Definition/ArrayNode.php b/src/Symfony/Component/Config/Definition/ArrayNode.php
index ea0453e7e951c..d7a3f0d80432a 100644
--- a/src/Symfony/Component/Config/Definition/ArrayNode.php
+++ b/src/Symfony/Component/Config/Definition/ArrayNode.php
@@ -332,11 +332,9 @@ protected function normalizeValue($value)
     /**
      * Remaps multiple singular values to a single plural value.
      *
-     * @param array $value The source values
-     *
      * @return array The remapped values
      */
-    protected function remapXml($value)
+    protected function remapXml(array $value)
     {
         foreach ($this->xmlRemappings as list($singular, $plural)) {
             if (!isset($value[$singular])) {
diff --git a/src/Symfony/Component/Config/Definition/Dumper/XmlReferenceDumper.php b/src/Symfony/Component/Config/Definition/Dumper/XmlReferenceDumper.php
index 6c14beee4b6f9..32f32e0a6b424 100644
--- a/src/Symfony/Component/Config/Definition/Dumper/XmlReferenceDumper.php
+++ b/src/Symfony/Component/Config/Definition/Dumper/XmlReferenceDumper.php
@@ -31,7 +31,7 @@ public function dump(ConfigurationInterface $configuration, string $namespace =
         return $this->dumpNode($configuration->getConfigTreeBuilder()->buildTree(), $namespace);
     }
 
-    public function dumpNode(NodeInterface $node, $namespace = null)
+    public function dumpNode(NodeInterface $node, string $namespace = null)
     {
         $this->reference = '';
         $this->writeNode($node, 0, true, $namespace);
diff --git a/src/Symfony/Component/Config/Definition/Dumper/YamlReferenceDumper.php b/src/Symfony/Component/Config/Definition/Dumper/YamlReferenceDumper.php
index c53481bd96a63..757963d42a9be 100644
--- a/src/Symfony/Component/Config/Definition/Dumper/YamlReferenceDumper.php
+++ b/src/Symfony/Component/Config/Definition/Dumper/YamlReferenceDumper.php
@@ -33,7 +33,7 @@ public function dump(ConfigurationInterface $configuration)
         return $this->dumpNode($configuration->getConfigTreeBuilder()->buildTree());
     }
 
-    public function dumpAtPath(ConfigurationInterface $configuration, $path)
+    public function dumpAtPath(ConfigurationInterface $configuration, string $path)
     {
         $rootNode = $node = $configuration->getConfigTreeBuilder()->buildTree();
 
diff --git a/src/Symfony/Component/Config/Definition/Exception/InvalidConfigurationException.php b/src/Symfony/Component/Config/Definition/Exception/InvalidConfigurationException.php
index 3dbc57b15317f..fcaaf49435f9d 100644
--- a/src/Symfony/Component/Config/Definition/Exception/InvalidConfigurationException.php
+++ b/src/Symfony/Component/Config/Definition/Exception/InvalidConfigurationException.php
@@ -34,10 +34,8 @@ public function getPath()
 
     /**
      * Adds extra information that is suffixed to the original exception message.
-     *
-     * @param string $hint
      */
-    public function addHint($hint)
+    public function addHint(string $hint)
     {
         if (!$this->containsHints) {
             $this->message .= "\nHint: ".$hint;
diff --git a/src/Symfony/Component/Config/FileLocator.php b/src/Symfony/Component/Config/FileLocator.php
index c817746d93702..965f940d45dcc 100644
--- a/src/Symfony/Component/Config/FileLocator.php
+++ b/src/Symfony/Component/Config/FileLocator.php
@@ -35,7 +35,7 @@ public function __construct($paths = [])
      */
     public function locate(string $name, string $currentPath = null, bool $first = true)
     {
-        if ('' == $name) {
+        if ('' === $name) {
             throw new \InvalidArgumentException('An empty file name is not valid to be located.');
         }
 
diff --git a/src/Symfony/Component/Config/Resource/ClassExistenceResource.php b/src/Symfony/Component/Config/Resource/ClassExistenceResource.php
index c6ba668977a1c..5eb1488ee3fbd 100644
--- a/src/Symfony/Component/Config/Resource/ClassExistenceResource.php
+++ b/src/Symfony/Component/Config/Resource/ClassExistenceResource.php
@@ -128,7 +128,7 @@ public function __sleep(): array
      *
      * @internal
      */
-    public static function throwOnRequiredClass($class, \Exception $previous = null)
+    public static function throwOnRequiredClass(string $class, \Exception $previous = null)
     {
         // If the passed class is the resource being checked, we shouldn't throw.
         if (null === $previous && self::$autoloadedClass === $class) {
diff --git a/src/Symfony/Component/Config/Util/XmlUtils.php b/src/Symfony/Component/Config/Util/XmlUtils.php
index 1d9e86561b31b..97b159a0c1391 100644
--- a/src/Symfony/Component/Config/Util/XmlUtils.php
+++ b/src/Symfony/Component/Config/Util/XmlUtils.php
@@ -247,7 +247,7 @@ public static function phpize($value)
         }
     }
 
-    protected static function getXmlErrors($internalErrors)
+    protected static function getXmlErrors(bool $internalErrors)
     {
         $errors = [];
         foreach (libxml_get_errors() as $error) {
diff --git a/src/Symfony/Component/Console/Question/ChoiceQuestion.php b/src/Symfony/Component/Console/Question/ChoiceQuestion.php
index a4b302db3e18f..020b733f132ac 100644
--- a/src/Symfony/Component/Console/Question/ChoiceQuestion.php
+++ b/src/Symfony/Component/Console/Question/ChoiceQuestion.php
@@ -58,11 +58,9 @@ public function getChoices()
      *
      * When multiselect is set to true, multiple choices can be answered.
      *
-     * @param bool $multiselect
-     *
      * @return $this
      */
-    public function setMultiselect($multiselect)
+    public function setMultiselect(bool $multiselect)
     {
         $this->multiselect = $multiselect;
         $this->setValidator($this->getDefaultValidator());
@@ -93,11 +91,9 @@ public function getPrompt()
     /**
      * Sets the prompt for choices.
      *
-     * @param string $prompt
-     *
      * @return $this
      */
-    public function setPrompt($prompt)
+    public function setPrompt(string $prompt)
     {
         $this->prompt = $prompt;
 
@@ -109,11 +105,9 @@ public function setPrompt($prompt)
      *
      * The error message has a string placeholder (%s) for the invalid value.
      *
-     * @param string $errorMessage
-     *
      * @return $this
      */
-    public function setErrorMessage($errorMessage)
+    public function setErrorMessage(string $errorMessage)
     {
         $this->errorMessage = $errorMessage;
         $this->setValidator($this->getDefaultValidator());
diff --git a/src/Symfony/Component/Console/Question/Question.php b/src/Symfony/Component/Console/Question/Question.php
index 6d02c4af0944f..a85851bc500bb 100644
--- a/src/Symfony/Component/Console/Question/Question.php
+++ b/src/Symfony/Component/Console/Question/Question.php
@@ -130,14 +130,11 @@ public function getAutocompleterValues()
     /**
      * Sets values for the autocompleter.
      *
-     * @param iterable|null $values
-     *
      * @return $this
      *
-     * @throws InvalidArgumentException
      * @throws LogicException
      */
-    public function setAutocompleterValues($values)
+    public function setAutocompleterValues(?iterable $values)
     {
         if (\is_array($values)) {
             $values = $this->isAssoc($values) ? array_merge(array_keys($values), array_values($values)) : array_values($values);
@@ -150,10 +147,8 @@ public function setAutocompleterValues($values)
             $callback = static function () use ($values, &$valueCache) {
                 return $valueCache ?? $valueCache = iterator_to_array($values, false);
             };
-        } elseif (null === $values) {
-            $callback = null;
         } else {
-            throw new InvalidArgumentException('Autocompleter values can be either an array, "null" or a "Traversable" object.');
+            $callback = null;
         }
 
         return $this->setAutocompleterCallback($callback);
@@ -212,13 +207,11 @@ public function getValidator()
      *
      * Null means an unlimited number of attempts.
      *
-     * @param int|null $attempts
-     *
      * @return $this
      *
      * @throws InvalidArgumentException in case the number of attempts is invalid
      */
-    public function setMaxAttempts($attempts)
+    public function setMaxAttempts(?int $attempts)
     {
         if (null !== $attempts && $attempts < 1) {
             throw new InvalidArgumentException('Maximum number of attempts must be a positive value.');
@@ -267,7 +260,7 @@ public function getNormalizer()
         return $this->normalizer;
     }
 
-    protected function isAssoc($array)
+    protected function isAssoc(array $array)
     {
         return (bool) \count(array_filter(array_keys($array), 'is_string'));
     }
diff --git a/src/Symfony/Component/Console/Tests/Question/QuestionTest.php b/src/Symfony/Component/Console/Tests/Question/QuestionTest.php
index 59b714291a8e2..9b3cabfc1da33 100644
--- a/src/Symfony/Component/Console/Tests/Question/QuestionTest.php
+++ b/src/Symfony/Component/Console/Tests/Question/QuestionTest.php
@@ -12,7 +12,6 @@
 namespace Symfony\Component\Console\Tests\Question;
 
 use PHPUnit\Framework\TestCase;
-use Symfony\Component\Console\Exception\InvalidArgumentException;
 use Symfony\Component\Console\Question\Question;
 
 class QuestionTest extends TestCase
@@ -150,10 +149,7 @@ public function providerSetAutocompleterValuesInvalid()
      */
     public function testSetAutocompleterValuesInvalid($values)
     {
-        self::expectException(InvalidArgumentException::class);
-        self::expectExceptionMessage(
-            'Autocompleter values can be either an array, "null" or a "Traversable" object.'
-        );
+        self::expectException(\TypeError::class);
 
         $this->question->setAutocompleterValues($values);
     }
@@ -271,7 +267,7 @@ public function testGetSetMaxAttempts($attempts)
 
     public function providerSetMaxAttemptsInvalid()
     {
-        return [['Potato'], [0], [-1]];
+        return [[0], [-1]];
     }
 
     /**
diff --git a/src/Symfony/Component/EventDispatcher/GenericEvent.php b/src/Symfony/Component/EventDispatcher/GenericEvent.php
index 62bd59c903c08..34b95cedee817 100644
--- a/src/Symfony/Component/EventDispatcher/GenericEvent.php
+++ b/src/Symfony/Component/EventDispatcher/GenericEvent.php
@@ -50,13 +50,11 @@ public function getSubject()
     /**
      * Get argument by key.
      *
-     * @param string $key Key
-     *
      * @return mixed Contents of array key
      *
      * @throws \InvalidArgumentException if key is not found
      */
-    public function getArgument($key)
+    public function getArgument(string $key)
     {
         if ($this->hasArgument($key)) {
             return $this->arguments[$key];
@@ -68,12 +66,11 @@ public function getArgument($key)
     /**
      * Add argument to event.
      *
-     * @param string $key   Argument name
-     * @param mixed  $value Value
+     * @param mixed $value Value
      *
      * @return $this
      */
-    public function setArgument($key, $value)
+    public function setArgument(string $key, $value)
     {
         $this->arguments[$key] = $value;
 
@@ -93,8 +90,6 @@ public function getArguments()
     /**
      * Set args property.
      *
-     * @param array $args Arguments
-     *
      * @return $this
      */
     public function setArguments(array $args = [])
@@ -107,11 +102,9 @@ public function setArguments(array $args = [])
     /**
      * Has argument.
      *
-     * @param string $key Key of arguments array
-     *
      * @return bool
      */
-    public function hasArgument($key)
+    public function hasArgument(string $key)
     {
         return \array_key_exists($key, $this->arguments);
     }
diff --git a/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToLocalizedStringTransformer.php b/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToLocalizedStringTransformer.php
index 325f61f11232e..2dfbbf17d60d1 100644
--- a/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToLocalizedStringTransformer.php
+++ b/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateTimeToLocalizedStringTransformer.php
@@ -158,7 +158,7 @@ public function reverseTransform($value)
      *
      * @throws TransformationFailedException in case the date formatter can not be constructed
      */
-    protected function getIntlDateFormatter($ignoreTimezone = false)
+    protected function getIntlDateFormatter(bool $ignoreTimezone = false)
     {
         $dateFormat = $this->dateFormat;
         $timeFormat = $this->timeFormat;
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/MoneyType.php b/src/Symfony/Component/Form/Extension/Core/Type/MoneyType.php
index 09a7383c23029..d402d311372b6 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/MoneyType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/MoneyType.php
@@ -87,7 +87,7 @@ public function getBlockPrefix()
      * The pattern contains the placeholder "{{ widget }}" where the HTML tag should
      * be inserted
      */
-    protected static function getPattern($currency)
+    protected static function getPattern(?string $currency)
     {
         if (!$currency) {
             return '{{ widget }}';
diff --git a/src/Symfony/Component/HttpFoundation/JsonResponse.php b/src/Symfony/Component/HttpFoundation/JsonResponse.php
index f2a4e60b13b60..8489bc0b16133 100644
--- a/src/Symfony/Component/HttpFoundation/JsonResponse.php
+++ b/src/Symfony/Component/HttpFoundation/JsonResponse.php
@@ -83,7 +83,7 @@ public static function create($data = null, int $status = 200, array $headers =
      *
      * @return static
      */
-    public static function fromJsonString($data = null, int $status = 200, array $headers = [])
+    public static function fromJsonString(string $data = null, int $status = 200, array $headers = [])
     {
         return new static($data, $status, $headers, true);
     }
diff --git a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php
index b84991e31b82d..920903082e6a8 100644
--- a/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php
+++ b/src/Symfony/Component/Ldap/Adapter/ExtLdap/Query.php
@@ -153,7 +153,7 @@ public function execute()
      *
      * @internal
      */
-    public function getResource($idx = 0)
+    public function getResource(int $idx = 0)
     {
         if (null === $this->results || $idx >= \count($this->results)) {
             return null;
diff --git a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
index 2a6620f270b96..48864761c165a 100644
--- a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
+++ b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
@@ -146,7 +146,7 @@ public function supportsClass(string $class)
      *
      * @return LdapUser
      */
-    protected function loadUser($username, Entry $entry)
+    protected function loadUser(string $username, Entry $entry)
     {
         $password = null;
         $extraFields = [];
diff --git a/src/Symfony/Component/Lock/Key.php b/src/Symfony/Component/Lock/Key.php
index c53892ab6bed2..bc09b888887b1 100644
--- a/src/Symfony/Component/Lock/Key.php
+++ b/src/Symfony/Component/Lock/Key.php
@@ -60,7 +60,7 @@ public function resetLifetime()
     /**
      * @param float $ttl the expiration delay of locks in seconds
      */
-    public function reduceLifetime($ttl)
+    public function reduceLifetime(float $ttl)
     {
         $newTime = microtime(true) + $ttl;
 
diff --git a/src/Symfony/Component/Mailer/Transport/Smtp/Stream/AbstractStream.php b/src/Symfony/Component/Mailer/Transport/Smtp/Stream/AbstractStream.php
index 623717fcafe07..f7b30a7b24216 100644
--- a/src/Symfony/Component/Mailer/Transport/Smtp/Stream/AbstractStream.php
+++ b/src/Symfony/Component/Mailer/Transport/Smtp/Stream/AbstractStream.php
@@ -30,7 +30,7 @@ abstract class AbstractStream
 
     private $debug = '';
 
-    public function write(string $bytes, $debug = true): void
+    public function write(string $bytes, bool $debug = true): void
     {
         if ($debug) {
             foreach (explode("\n", trim($bytes)) as $line) {
diff --git a/src/Symfony/Component/Messenger/Transport/Doctrine/Connection.php b/src/Symfony/Component/Messenger/Transport/Doctrine/Connection.php
index 67817a3d86ab1..782e44677584d 100644
--- a/src/Symfony/Component/Messenger/Transport/Doctrine/Connection.php
+++ b/src/Symfony/Component/Messenger/Transport/Doctrine/Connection.php
@@ -63,7 +63,7 @@ public function getConfiguration(): array
         return $this->configuration;
     }
 
-    public static function buildConfiguration($dsn, array $options = []): array
+    public static function buildConfiguration(string $dsn, array $options = []): array
     {
         if (false === $components = parse_url($dsn)) {
             throw new InvalidArgumentException(sprintf('The given Doctrine Messenger DSN "%s" is invalid.', $dsn));
diff --git a/src/Symfony/Component/Messenger/Worker.php b/src/Symfony/Component/Messenger/Worker.php
index d531b1af3f512..e872c9642bf83 100644
--- a/src/Symfony/Component/Messenger/Worker.php
+++ b/src/Symfony/Component/Messenger/Worker.php
@@ -178,7 +178,7 @@ public function stop(): void
         $this->shouldStop = true;
     }
 
-    private function dispatchEvent($event)
+    private function dispatchEvent(object $event): void
     {
         if (null === $this->eventDispatcher) {
             return;
diff --git a/src/Symfony/Component/Process/Process.php b/src/Symfony/Component/Process/Process.php
index 2f6cc944545cb..db9e7a2735eac 100644
--- a/src/Symfony/Component/Process/Process.php
+++ b/src/Symfony/Component/Process/Process.php
@@ -602,7 +602,7 @@ public function getIncrementalOutput()
      *
      * @return \Generator
      */
-    public function getIterator($flags = 0)
+    public function getIterator(int $flags = 0)
     {
         $this->readPipesForOutput(__FUNCTION__, false);
 
@@ -995,13 +995,11 @@ public function getIdleTimeout()
      *
      * To disable the timeout, set this value to null.
      *
-     * @param int|float|null $timeout The timeout in seconds
-     *
      * @return $this
      *
      * @throws InvalidArgumentException if the timeout is negative
      */
-    public function setTimeout($timeout)
+    public function setTimeout(?float $timeout)
     {
         $this->timeout = $this->validateTimeout($timeout);
 
@@ -1009,18 +1007,16 @@ public function setTimeout($timeout)
     }
 
     /**
-     * Sets the process idle timeout (max. time since last output).
+     * Sets the process idle timeout (max. time since last output) in seconds.
      *
      * To disable the timeout, set this value to null.
      *
-     * @param int|float|null $timeout The timeout in seconds
-     *
      * @return $this
      *
      * @throws LogicException           if the output is disabled
      * @throws InvalidArgumentException if the timeout is negative
      */
-    public function setIdleTimeout($timeout)
+    public function setIdleTimeout(?float $timeout)
     {
         if (null !== $timeout && $this->outputDisabled) {
             throw new LogicException('Idle timeout can not be set while the output is disabled.');
@@ -1048,7 +1044,7 @@ public function setTty(bool $tty)
             throw new RuntimeException('TTY mode requires /dev/tty to be read/writable.');
         }
 
-        $this->tty = (bool) $tty;
+        $this->tty = $tty;
 
         return $this;
     }
diff --git a/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php b/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
index 642924dd924fb..476e75a413d47 100644
--- a/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
+++ b/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
@@ -131,7 +131,7 @@ public function getProperties(string $class, array $context = []): ?array
     /**
      * {@inheritdoc}
      */
-    public function getTypes(string $class, $property, array $context = []): ?array
+    public function getTypes(string $class, string $property, array $context = []): ?array
     {
         if ($fromMutator = $this->extractFromMutator($class, $property)) {
             return $fromMutator;
@@ -158,7 +158,7 @@ public function getTypes(string $class, $property, array $context = []): ?array
     /**
      * {@inheritdoc}
      */
-    public function isReadable(string $class, $property, array $context = []): ?bool
+    public function isReadable(string $class, string $property, array $context = []): ?bool
     {
         if ($this->isAllowedProperty($class, $property)) {
             return true;
@@ -172,7 +172,7 @@ public function isReadable(string $class, $property, array $context = []): ?bool
     /**
      * {@inheritdoc}
      */
-    public function isWritable(string $class, $property, array $context = []): ?bool
+    public function isWritable(string $class, string $property, array $context = []): ?bool
     {
         if ($this->isAllowedProperty($class, $property)) {
             return true;
diff --git a/src/Symfony/Component/Security/Core/Exception/CustomUserMessageAuthenticationException.php b/src/Symfony/Component/Security/Core/Exception/CustomUserMessageAuthenticationException.php
index b64d267b4868c..f082377fa0082 100644
--- a/src/Symfony/Component/Security/Core/Exception/CustomUserMessageAuthenticationException.php
+++ b/src/Symfony/Component/Security/Core/Exception/CustomUserMessageAuthenticationException.php
@@ -39,7 +39,7 @@ public function __construct(string $message = '', array $messageData = [], int $
      * @param string $messageKey  The message or message key
      * @param array  $messageData Data to be passed into the translator
      */
-    public function setSafeMessage($messageKey, array $messageData = [])
+    public function setSafeMessage(string $messageKey, array $messageData = [])
     {
         $this->messageKey = $messageKey;
         $this->messageData = $messageData;
diff --git a/src/Symfony/Component/Security/Core/Exception/UsernameNotFoundException.php b/src/Symfony/Component/Security/Core/Exception/UsernameNotFoundException.php
index 31dd486eec12d..e1f816bc6b094 100644
--- a/src/Symfony/Component/Security/Core/Exception/UsernameNotFoundException.php
+++ b/src/Symfony/Component/Security/Core/Exception/UsernameNotFoundException.php
@@ -41,10 +41,8 @@ public function getUsername()
 
     /**
      * Set the username.
-     *
-     * @param string $username
      */
-    public function setUsername($username)
+    public function setUsername(string $username)
     {
         $this->username = $username;
     }
diff --git a/src/Symfony/Component/Security/Http/Logout/LogoutUrlGenerator.php b/src/Symfony/Component/Security/Http/Logout/LogoutUrlGenerator.php
index 6d134c4ab3381..c6b721209f363 100644
--- a/src/Symfony/Component/Security/Http/Logout/LogoutUrlGenerator.php
+++ b/src/Symfony/Component/Security/Http/Logout/LogoutUrlGenerator.php
@@ -47,7 +47,7 @@ public function __construct(RequestStack $requestStack = null, UrlGeneratorInter
      * @param string|null $csrfParameter The CSRF token parameter name
      * @param string|null $context       The listener context
      */
-    public function registerListener($key, $logoutPath, $csrfTokenId, $csrfParameter, CsrfTokenManagerInterface $csrfTokenManager = null, string $context = null)
+    public function registerListener(string $key, string $logoutPath, ?string $csrfTokenId, ?string $csrfParameter, CsrfTokenManagerInterface $csrfTokenManager = null, string $context = null)
     {
         $this->listeners[$key] = [$logoutPath, $csrfTokenId, $csrfParameter, $csrfTokenManager, $context];
     }
diff --git a/src/Symfony/Component/Translation/DataCollectorTranslator.php b/src/Symfony/Component/Translation/DataCollectorTranslator.php
index fedc79ccd13b5..c46e058c9ecbd 100644
--- a/src/Symfony/Component/Translation/DataCollectorTranslator.php
+++ b/src/Symfony/Component/Translation/DataCollectorTranslator.php
@@ -106,7 +106,7 @@ public function getFallbackLocales()
     /**
      * Passes through all unknown calls onto the translator object.
      */
-    public function __call($method, $args)
+    public function __call(string $method, array $args)
     {
         return $this->translator->{$method}(...$args);
     }
diff --git a/src/Symfony/Component/Translation/Extractor/PhpExtractor.php b/src/Symfony/Component/Translation/Extractor/PhpExtractor.php
index db9c2bda4e5e7..aa2ebc637dbb3 100644
--- a/src/Symfony/Component/Translation/Extractor/PhpExtractor.php
+++ b/src/Symfony/Component/Translation/Extractor/PhpExtractor.php
@@ -226,13 +226,11 @@ protected function parseTokens(array $tokens, MessageCatalogue $catalog, string
     }
 
     /**
-     * @param string $file
-     *
      * @return bool
      *
      * @throws \InvalidArgumentException
      */
-    protected function canBeExtracted($file)
+    protected function canBeExtracted(string $file)
     {
         return $this->isFile($file) && 'php' === pathinfo($file, PATHINFO_EXTENSION);
     }
diff --git a/src/Symfony/Component/Translation/LoggingTranslator.php b/src/Symfony/Component/Translation/LoggingTranslator.php
index 2f09747956ffc..2c9e97c1e9052 100644
--- a/src/Symfony/Component/Translation/LoggingTranslator.php
+++ b/src/Symfony/Component/Translation/LoggingTranslator.php
@@ -99,7 +99,7 @@ public function getFallbackLocales()
     /**
      * Passes through all unknown calls onto the translator object.
      */
-    public function __call($method, $args)
+    public function __call(string $method, array $args)
     {
         return $this->translator->{$method}(...$args);
     }
diff --git a/src/Symfony/Component/Translation/Translator.php b/src/Symfony/Component/Translation/Translator.php
index 945e16bf321d1..0ecfee378b83d 100644
--- a/src/Symfony/Component/Translation/Translator.php
+++ b/src/Symfony/Component/Translation/Translator.php
@@ -86,7 +86,7 @@ class Translator implements TranslatorInterface, TranslatorBagInterface, LocaleA
      */
     public function __construct(string $locale, MessageFormatterInterface $formatter = null, string $cacheDir = null, bool $debug = false)
     {
-        $this->setLocale($locale, false);
+        $this->setLocale($locale);
 
         if (null === $formatter) {
             $formatter = new MessageFormatter();
@@ -118,8 +118,6 @@ public function addLoader(string $format, LoaderInterface $loader)
      *
      * @param string $format   The name of the loader (@see addLoader())
      * @param mixed  $resource The resource name
-     * @param string $locale   The locale
-     * @param string $domain   The domain
      *
      * @throws InvalidArgumentException If the locale contains invalid characters
      */
@@ -383,7 +381,7 @@ private function loadFallbackCatalogues(string $locale): void
         }
     }
 
-    protected function computeFallbackLocales($locale)
+    protected function computeFallbackLocales(string $locale)
     {
         if (null === $this->parentLocales) {
             $parentLocales = json_decode(file_get_contents(__DIR__.'/Resources/data/parents.json'), true);
diff --git a/src/Symfony/Component/VarExporter/Internal/Exporter.php b/src/Symfony/Component/VarExporter/Internal/Exporter.php
index 87b3156d41efd..de7c9fcbe3967 100644
--- a/src/Symfony/Component/VarExporter/Internal/Exporter.php
+++ b/src/Symfony/Component/VarExporter/Internal/Exporter.php
@@ -187,7 +187,7 @@ public static function prepare($values, $objectsPool, &$refsPool, &$objectsCount
         return $values;
     }
 
-    public static function export($value, $indent = '')
+    public static function export($value, string $indent = '')
     {
         switch (true) {
             case \is_int($value) || \is_float($value): return var_export($value, true);
diff --git a/src/Symfony/Component/Workflow/Event/GuardEvent.php b/src/Symfony/Component/Workflow/Event/GuardEvent.php
index 2004fa6162629..e287b004af969 100644
--- a/src/Symfony/Component/Workflow/Event/GuardEvent.php
+++ b/src/Symfony/Component/Workflow/Event/GuardEvent.php
@@ -40,7 +40,7 @@ public function isBlocked()
         return !$this->transitionBlockerList->isEmpty();
     }
 
-    public function setBlocked($blocked)
+    public function setBlocked(bool $blocked)
     {
         if (!$blocked) {
             $this->transitionBlockerList->clear();
diff --git a/src/Symfony/Component/Workflow/Registry.php b/src/Symfony/Component/Workflow/Registry.php
index c65f238f339a9..e9e73b1889ecc 100644
--- a/src/Symfony/Component/Workflow/Registry.php
+++ b/src/Symfony/Component/Workflow/Registry.php
@@ -65,11 +65,7 @@ public function all(object $subject): array
         return $matched;
     }
 
-    /**
-     * @param WorkflowSupportStrategyInterface $supportStrategy
-     * @param object                           $subject
-     */
-    private function supports(WorkflowInterface $workflow, $supportStrategy, $subject, ?string $workflowName): bool
+    private function supports(WorkflowInterface $workflow, WorkflowSupportStrategyInterface $supportStrategy, object $subject, ?string $workflowName): bool
     {
         if (null !== $workflowName && $workflowName !== $workflow->getName()) {
             return false;