diff --git a/src/Symfony/Bridge/Doctrine/Form/ChoiceList/IdReader.php b/src/Symfony/Bridge/Doctrine/Form/ChoiceList/IdReader.php
index 4140629d934b6..a04be3a7900a6 100644
--- a/src/Symfony/Bridge/Doctrine/Form/ChoiceList/IdReader.php
+++ b/src/Symfony/Bridge/Doctrine/Form/ChoiceList/IdReader.php
@@ -82,7 +82,7 @@ public function __construct(ObjectManager $om, ClassMetadata $classMetadata)
      * @return bool Returns `true` if the class has a single-column ID and
      *              `false` otherwise.
      */
-    public function isSingleId()
+    public function isSingleId(): bool
     {
         return $this->singleId;
     }
@@ -93,7 +93,7 @@ public function isSingleId()
      * @return bool Returns `true` if the class has a single-column integer ID
      *              and `false` otherwise.
      */
-    public function isIntId()
+    public function isIntId(): bool
     {
         return $this->intId;
     }
@@ -138,7 +138,7 @@ public function getIdValue($object)
      *
      * @return string The name of the ID field
      */
-    public function getIdField()
+    public function getIdField(): string
     {
         return $this->idField;
     }
diff --git a/src/Symfony/Bundle/SecurityBundle/Debug/WrappedListener.php b/src/Symfony/Bundle/SecurityBundle/Debug/WrappedListener.php
index 435ecc5feb573..85878e2193882 100644
--- a/src/Symfony/Bundle/SecurityBundle/Debug/WrappedListener.php
+++ b/src/Symfony/Bundle/SecurityBundle/Debug/WrappedListener.php
@@ -56,12 +56,12 @@ public function __call($method, $arguments)
         return call_user_func_array(array($this->listener, $method), $arguments);
     }
 
-    public function getWrappedListener()
+    public function getWrappedListener(): ListenerInterface
     {
         return $this->listener;
     }
 
-    public function getInfo()
+    public function getInfo(): array
     {
         if (null === $this->stub) {
             $this->stub = self::$hasVarDumper ? new ClassStub(get_class($this->listener)) : get_class($this->listener);
diff --git a/src/Symfony/Bundle/SecurityBundle/Security/FirewallConfig.php b/src/Symfony/Bundle/SecurityBundle/Security/FirewallConfig.php
index 62317f625c271..308442810bba8 100644
--- a/src/Symfony/Bundle/SecurityBundle/Security/FirewallConfig.php
+++ b/src/Symfony/Bundle/SecurityBundle/Security/FirewallConfig.php
@@ -29,21 +29,7 @@ final class FirewallConfig
     private $listeners;
     private $switchUser;
 
-    /**
-     * @param string      $name
-     * @param string      $userChecker
-     * @param string|null $requestMatcher
-     * @param bool        $securityEnabled
-     * @param bool        $stateless
-     * @param string|null $provider
-     * @param string|null $context
-     * @param string|null $entryPoint
-     * @param string|null $accessDeniedHandler
-     * @param string|null $accessDeniedUrl
-     * @param string[]    $listeners
-     * @param array|null  $switchUser
-     */
-    public function __construct($name, $userChecker, $requestMatcher = null, $securityEnabled = true, $stateless = false, $provider = null, $context = null, $entryPoint = null, $accessDeniedHandler = null, $accessDeniedUrl = null, $listeners = array(), $switchUser = null)
+    public function __construct(string $name, string $userChecker, string $requestMatcher = null, bool $securityEnabled = true, bool $stateless = false, string $provider = null, string $context = null, string $entryPoint = null, string $accessDeniedHandler = null, string $accessDeniedUrl = null, array $listeners = array(), $switchUser = null)
     {
         $this->name = $name;
         $this->userChecker = $userChecker;
@@ -59,7 +45,7 @@ public function __construct($name, $userChecker, $requestMatcher = null, $securi
         $this->switchUser = $switchUser;
     }
 
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
@@ -68,30 +54,27 @@ public function getName()
      * @return string|null The request matcher service id or null if neither the request matcher, pattern or host
      *                     options were provided
      */
-    public function getRequestMatcher()
+    public function getRequestMatcher(): ?string
     {
         return $this->requestMatcher;
     }
 
-    public function isSecurityEnabled()
+    public function isSecurityEnabled(): bool
     {
         return $this->securityEnabled;
     }
 
-    public function allowsAnonymous()
+    public function allowsAnonymous(): bool
     {
         return in_array('anonymous', $this->listeners, true);
     }
 
-    public function isStateless()
+    public function isStateless(): bool
     {
         return $this->stateless;
     }
 
-    /**
-     * @return string|null The provider service id
-     */
-    public function getProvider()
+    public function getProvider(): ?string
     {
         return $this->provider;
     }
@@ -99,55 +82,37 @@ public function getProvider()
     /**
      * @return string|null The context key (will be null if the firewall is stateless)
      */
-    public function getContext()
+    public function getContext(): ?string
     {
         return $this->context;
     }
 
-    /**
-     * @return string|null The entry_point service id if configured, null otherwise
-     */
-    public function getEntryPoint()
+    public function getEntryPoint(): ?string
     {
         return $this->entryPoint;
     }
 
-    /**
-     * @return string The user_checker service id
-     */
-    public function getUserChecker()
+    public function getUserChecker(): string
     {
         return $this->userChecker;
     }
 
-    /**
-     * @return string|null The access_denied_handler service id if configured, null otherwise
-     */
-    public function getAccessDeniedHandler()
+    public function getAccessDeniedHandler(): ?string
     {
         return $this->accessDeniedHandler;
     }
 
-    /**
-     * @return string|null The access_denied_handler URL if configured, null otherwise
-     */
-    public function getAccessDeniedUrl()
+    public function getAccessDeniedUrl(): ?string
     {
         return $this->accessDeniedUrl;
     }
 
-    /**
-     * @return string[] An array of listener keys
-     */
-    public function getListeners()
+    public function getListeners(): array
     {
         return $this->listeners;
     }
 
-    /**
-     * @return array|null The switch_user parameters if configured, null otherwise
-     */
-    public function getSwitchUser()
+    public function getSwitchUser(): ?array
     {
         return $this->switchUser;
     }
diff --git a/src/Symfony/Bundle/SecurityBundle/Tests/Security/FirewallMapTest.php b/src/Symfony/Bundle/SecurityBundle/Tests/Security/FirewallMapTest.php
index f9047cfdd233e..3e6f0a1ac74c6 100644
--- a/src/Symfony/Bundle/SecurityBundle/Tests/Security/FirewallMapTest.php
+++ b/src/Symfony/Bundle/SecurityBundle/Tests/Security/FirewallMapTest.php
@@ -18,7 +18,6 @@
 use Symfony\Component\DependencyInjection\Container;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestMatcherInterface;
-use Symfony\Component\Security\Core\User\UserCheckerInterface;
 use Symfony\Component\Security\Http\Firewall\ExceptionListener;
 use Symfony\Component\Security\Http\Firewall\ListenerInterface;
 
@@ -63,7 +62,7 @@ public function testGetListeners()
 
         $firewallContext = $this->getMockBuilder(FirewallContext::class)->disableOriginalConstructor()->getMock();
 
-        $firewallConfig = new FirewallConfig('main', $this->getMockBuilder(UserCheckerInterface::class)->getMock());
+        $firewallConfig = new FirewallConfig('main', 'user_checker');
         $firewallContext->expects($this->once())->method('getConfig')->willReturn($firewallConfig);
 
         $listener = $this->getMockBuilder(ListenerInterface::class)->getMock();
diff --git a/src/Symfony/Component/Config/Loader/FileLoader.php b/src/Symfony/Component/Config/Loader/FileLoader.php
index 02aa811fc5497..9fb5faa7a9bcd 100644
--- a/src/Symfony/Component/Config/Loader/FileLoader.php
+++ b/src/Symfony/Component/Config/Loader/FileLoader.php
@@ -81,7 +81,7 @@ public function getLocator()
      * @throws FileLoaderImportCircularReferenceException
      * @throws FileLocatorFileNotFoundException
      */
-    public function import($resource, $type = null, $ignoreErrors = false, $sourceResource = null)
+    public function import($resource, $type = null, bool $ignoreErrors = false, $sourceResource = null)
     {
         if (is_string($resource) && strlen($resource) !== $i = strcspn($resource, '*?{[')) {
             $ret = array();
@@ -104,7 +104,7 @@ public function import($resource, $type = null, $ignoreErrors = false, $sourceRe
     /**
      * @internal
      */
-    protected function glob($pattern, $recursive, &$resource = null, $ignoreErrors = false)
+    protected function glob(string $pattern, bool $recursive, &$resource = null, bool $ignoreErrors = false)
     {
         if (strlen($pattern) === $i = strcspn($pattern, '*?{[')) {
             $prefix = $pattern;
@@ -138,7 +138,7 @@ protected function glob($pattern, $recursive, &$resource = null, $ignoreErrors =
         }
     }
 
-    private function doImport($resource, $type = null, $ignoreErrors = false, $sourceResource = null)
+    private function doImport($resource, $type = null, bool $ignoreErrors = false, $sourceResource = null)
     {
         try {
             $loader = $this->resolve($resource, $type);
diff --git a/src/Symfony/Component/Console/Event/ConsoleErrorEvent.php b/src/Symfony/Component/Console/Event/ConsoleErrorEvent.php
index 49edb723d212d..038d97af8aed7 100644
--- a/src/Symfony/Component/Console/Event/ConsoleErrorEvent.php
+++ b/src/Symfony/Component/Console/Event/ConsoleErrorEvent.php
@@ -12,7 +12,6 @@
 namespace Symfony\Component\Console\Event;
 
 use Symfony\Component\Console\Command\Command;
-use Symfony\Component\Console\Exception\InvalidArgumentException;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 
@@ -26,57 +25,33 @@ final class ConsoleErrorEvent extends ConsoleEvent
     private $error;
     private $exitCode;
 
-    public function __construct(InputInterface $input, OutputInterface $output, $error, Command $command = null)
+    public function __construct(InputInterface $input, OutputInterface $output, \Throwable $error, Command $command = null)
     {
         parent::__construct($command, $input, $output);
 
-        $this->setError($error);
+        $this->error = $error;
     }
 
-    /**
-     * Returns the thrown error/exception.
-     *
-     * @return \Throwable
-     */
-    public function getError()
+    public function getError(): \Throwable
     {
         return $this->error;
     }
 
-    /**
-     * Replaces the thrown error/exception.
-     *
-     * @param \Throwable $error
-     */
-    public function setError($error)
+    public function setError(\Throwable $error): void
     {
-        if (!$error instanceof \Throwable && !$error instanceof \Exception) {
-            throw new InvalidArgumentException(sprintf('The error passed to ConsoleErrorEvent must be an instance of \Throwable or \Exception, "%s" was passed instead.', is_object($error) ? get_class($error) : gettype($error)));
-        }
-
         $this->error = $error;
     }
 
-    /**
-     * Sets the exit code.
-     *
-     * @param int $exitCode The command exit code
-     */
-    public function setExitCode($exitCode)
+    public function setExitCode(int $exitCode): void
     {
-        $this->exitCode = (int) $exitCode;
+        $this->exitCode = $exitCode;
 
         $r = new \ReflectionProperty($this->error, 'code');
         $r->setAccessible(true);
         $r->setValue($this->error, $this->exitCode);
     }
 
-    /**
-     * Gets the exit code.
-     *
-     * @return int The command exit code
-     */
-    public function getExitCode()
+    public function getExitCode(): int
     {
         return null !== $this->exitCode ? $this->exitCode : ($this->error->getCode() ?: 1);
     }
diff --git a/src/Symfony/Component/Console/Helper/ProgressBar.php b/src/Symfony/Component/Console/Helper/ProgressBar.php
index 31c49ef730f02..6177a87a8322d 100644
--- a/src/Symfony/Component/Console/Helper/ProgressBar.php
+++ b/src/Symfony/Component/Console/Helper/ProgressBar.php
@@ -55,7 +55,7 @@ final class ProgressBar
      * @param OutputInterface $output An OutputInterface instance
      * @param int             $max    Maximum steps (0 if unknown)
      */
-    public function __construct(OutputInterface $output, $max = 0)
+    public function __construct(OutputInterface $output, int $max = 0)
     {
         if ($output instanceof ConsoleOutputInterface) {
             $output = $output->getErrorOutput();
@@ -84,7 +84,7 @@ public function __construct(OutputInterface $output, $max = 0)
      * @param string   $name     The placeholder name (including the delimiter char like %)
      * @param callable $callable A PHP callable
      */
-    public static function setPlaceholderFormatterDefinition($name, callable $callable)
+    public static function setPlaceholderFormatterDefinition(string $name, callable $callable): void
     {
         if (!self::$formatters) {
             self::$formatters = self::initPlaceholderFormatters();
@@ -100,7 +100,7 @@ public static function setPlaceholderFormatterDefinition($name, callable $callab
      *
      * @return callable|null A PHP callable
      */
-    public static function getPlaceholderFormatterDefinition($name)
+    public static function getPlaceholderFormatterDefinition(string $name): ?callable
     {
         if (!self::$formatters) {
             self::$formatters = self::initPlaceholderFormatters();
@@ -117,7 +117,7 @@ public static function getPlaceholderFormatterDefinition($name)
      * @param string $name   The format name
      * @param string $format A format string
      */
-    public static function setFormatDefinition($name, $format)
+    public static function setFormatDefinition(string $name, string $format): void
     {
         if (!self::$formats) {
             self::$formats = self::initFormats();
@@ -133,7 +133,7 @@ public static function setFormatDefinition($name, $format)
      *
      * @return string|null A format string
      */
-    public static function getFormatDefinition($name)
+    public static function getFormatDefinition(string $name): ?string
     {
         if (!self::$formats) {
             self::$formats = self::initFormats();
@@ -152,102 +152,57 @@ public static function getFormatDefinition($name)
      * @param string $message The text to associate with the placeholder
      * @param string $name    The name of the placeholder
      */
-    public function setMessage($message, $name = 'message')
+    public function setMessage(string $message, string $name = 'message')
     {
         $this->messages[$name] = $message;
     }
 
-    public function getMessage($name = 'message')
+    public function getMessage(string $name = 'message')
     {
         return $this->messages[$name];
     }
 
-    /**
-     * Gets the progress bar start time.
-     *
-     * @return int The progress bar start time
-     */
-    public function getStartTime()
+    public function getStartTime(): int
     {
         return $this->startTime;
     }
 
-    /**
-     * Gets the progress bar maximal steps.
-     *
-     * @return int The progress bar max steps
-     */
-    public function getMaxSteps()
+    public function getMaxSteps(): int
     {
         return $this->max;
     }
 
-    /**
-     * Gets the current step position.
-     *
-     * @return int The progress bar step
-     */
-    public function getProgress()
+    public function getProgress(): int
     {
         return $this->step;
     }
 
-    /**
-     * Gets the progress bar step width.
-     *
-     * @return int The progress bar step width
-     */
-    private function getStepWidth()
+    private function getStepWidth(): int
     {
         return $this->stepWidth;
     }
 
-    /**
-     * Gets the current progress bar percent.
-     *
-     * @return float The current progress bar percent
-     */
-    public function getProgressPercent()
+    public function getProgressPercent(): float
     {
         return $this->percent;
     }
 
-    /**
-     * Sets the progress bar width.
-     *
-     * @param int $size The progress bar size
-     */
-    public function setBarWidth($size)
+    public function setBarWidth(int $size)
     {
-        $this->barWidth = max(1, (int) $size);
+        $this->barWidth = max(1, $size);
     }
 
-    /**
-     * Gets the progress bar width.
-     *
-     * @return int The progress bar size
-     */
-    public function getBarWidth()
+    public function getBarWidth(): int
     {
         return $this->barWidth;
     }
 
-    /**
-     * Sets the bar character.
-     *
-     * @param string $char A character
-     */
-    public function setBarCharacter($char)
+    public function setBarCharacter(string $char)
     {
         $this->barChar = $char;
     }
 
-    /**
-     * Gets the bar character.
-     *
-     * @return string A character
-     */
-    public function getBarCharacter()
+    public function getBarCharacter(): string
     {
         if (null === $this->barChar) {
             return $this->max ? '=' : $this->emptyBarChar;
@@ -256,52 +211,27 @@ public function getBarCharacter()
         return $this->barChar;
     }
 
-    /**
-     * Sets the empty bar character.
-     *
-     * @param string $char A character
-     */
-    public function setEmptyBarCharacter($char)
+    public function setEmptyBarCharacter(string $char)
     {
         $this->emptyBarChar = $char;
     }
 
-    /**
-     * Gets the empty bar character.
-     *
-     * @return string A character
-     */
-    public function getEmptyBarCharacter()
+    public function getEmptyBarCharacter(): string
     {
         return $this->emptyBarChar;
     }
 
-    /**
-     * Sets the progress bar character.
-     *
-     * @param string $char A character
-     */
-    public function setProgressCharacter($char)
+    public function setProgressCharacter(string $char)
     {
         $this->progressChar = $char;
     }
 
-    /**
-     * Gets the progress bar character.
-     *
-     * @return string A character
-     */
-    public function getProgressCharacter()
+    public function getProgressCharacter(): string
     {
         return $this->progressChar;
     }
 
-    /**
-     * Sets the progress bar format.
-     *
-     * @param string $format The format
-     */
-    public function setFormat($format)
+    public function setFormat(string $format)
     {
         $this->format = null;
         $this->internalFormat = $format;
@@ -312,9 +242,9 @@ public function setFormat($format)
      *
      * @param int|float $freq The frequency in steps
      */
-    public function setRedrawFrequency($freq)
+    public function setRedrawFrequency(int $freq)
     {
-        $this->redrawFreq = max((int) $freq, 1);
+        $this->redrawFreq = max($freq, 1);
     }
 
     /**
@@ -322,7 +252,7 @@ public function setRedrawFrequency($freq)
      *
      * @param int|null $max Number of steps to complete the bar (0 if indeterminate), null to leave unchanged
      */
-    public function start($max = null)
+    public function start(int $max = null)
     {
         $this->startTime = time();
         $this->step = 0;
@@ -340,7 +270,7 @@ public function start($max = null)
      *
      * @param int $step Number of steps to advance
      */
-    public function advance($step = 1)
+    public function advance(int $step = 1)
     {
         $this->setProgress($this->step + $step);
     }
@@ -350,20 +280,13 @@ public function advance($step = 1)
      *
      * @param bool $overwrite
      */
-    public function setOverwrite($overwrite)
+    public function setOverwrite(bool $overwrite)
     {
-        $this->overwrite = (bool) $overwrite;
+        $this->overwrite = $overwrite;
     }
 
-    /**
-     * Sets the current progress.
-     *
-     * @param int $step The current progress
-     */
-    public function setProgress($step)
+    public function setProgress(int $step)
     {
-        $step = (int) $step;
-
         if ($this->max && $step > $this->max) {
             $this->max = $step;
         } elseif ($step < 0) {
@@ -382,7 +305,7 @@ public function setProgress($step)
     /**
      * Finishes the progress output.
      */
-    public function finish()
+    public function finish(): void
     {
         if (!$this->max) {
             $this->max = $this->step;
@@ -399,7 +322,7 @@ public function finish()
     /**
      * Outputs the current progress string.
      */
-    public function display()
+    public function display(): void
     {
         if (OutputInterface::VERBOSITY_QUIET === $this->output->getVerbosity()) {
             return;
@@ -419,7 +342,7 @@ public function display()
      * while a progress bar is running.
      * Call display() to show the progress bar again.
      */
-    public function clear()
+    public function clear(): void
     {
         if (!$this->overwrite) {
             return;
@@ -432,12 +355,7 @@ public function clear()
         $this->overwrite('');
     }
 
-    /**
-     * Sets the progress bar format.
-     *
-     * @param string $format The format
-     */
-    private function setRealFormat($format)
+    private function setRealFormat(string $format)
     {
         // try to use the _nomax variant if available
         if (!$this->max && null !== self::getFormatDefinition($format.'_nomax')) {
@@ -451,15 +369,10 @@ private function setRealFormat($format)
         $this->formatLineCount = substr_count($this->format, "\n");
     }
 
-    /**
-     * Sets the progress bar maximal steps.
-     *
-     * @param int $max The progress bar max steps
-     */
-    private function setMaxSteps($max)
+    private function setMaxSteps(int $max)
     {
-        $this->max = max(0, (int) $max);
-        $this->stepWidth = $this->max ? Helper::strlen($this->max) : 4;
+        $this->max = max(0, $max);
+        $this->stepWidth = $this->max ? Helper::strlen((string) $this->max) : 4;
     }
 
     /**
@@ -467,7 +380,7 @@ private function setMaxSteps($max)
      *
      * @param string $message The message
      */
-    private function overwrite($message)
+    private function overwrite(string $message): void
     {
         if ($this->overwrite) {
             if (!$this->firstRun) {
@@ -491,7 +404,7 @@ private function overwrite($message)
         $this->output->write($message);
     }
 
-    private function determineBestFormat()
+    private function determineBestFormat(): string
     {
         switch ($this->output->getVerbosity()) {
             // OutputInterface::VERBOSITY_QUIET: display is disabled anyway
@@ -506,7 +419,7 @@ private function determineBestFormat()
         }
     }
 
-    private static function initPlaceholderFormatters()
+    private static function initPlaceholderFormatters(): array
     {
         return array(
             'bar' => function (ProgressBar $bar, OutputInterface $output) {
@@ -563,7 +476,7 @@ private static function initPlaceholderFormatters()
         );
     }
 
-    private static function initFormats()
+    private static function initFormats(): array
     {
         return array(
             'normal' => ' %current%/%max% [%bar%] %percent:3s%%',
@@ -580,10 +493,7 @@ private static function initFormats()
         );
     }
 
-    /**
-     * @return string
-     */
-    private function buildLine()
+    private function buildLine(): string
     {
         $regex = "{%([a-z\-_]+)(?:\:([^%]+))?%}i";
         $callback = function ($matches) {
diff --git a/src/Symfony/Component/Console/Style/SymfonyStyle.php b/src/Symfony/Component/Console/Style/SymfonyStyle.php
index a86796176717e..c15ae4660001f 100644
--- a/src/Symfony/Component/Console/Style/SymfonyStyle.php
+++ b/src/Symfony/Component/Console/Style/SymfonyStyle.php
@@ -344,10 +344,7 @@ public function getErrorStyle()
         return new self($this->input, $this->getErrorOutput());
     }
 
-    /**
-     * @return ProgressBar
-     */
-    private function getProgressBar()
+    private function getProgressBar(): ProgressBar
     {
         if (!$this->progressBar) {
             throw new RuntimeException('The ProgressBar is not started.');
@@ -356,18 +353,20 @@ private function getProgressBar()
         return $this->progressBar;
     }
 
-    private function autoPrependBlock()
+    private function autoPrependBlock(): void
     {
         $chars = substr(str_replace(PHP_EOL, "\n", $this->bufferedOutput->fetch()), -2);
 
         if (!isset($chars[0])) {
-            return $this->newLine(); //empty history, so we should start with a new line.
+            $this->newLine(); //empty history, so we should start with a new line.
+
+            return;
         }
         //Prepend new line for each non LF chars (This means no blank line was output before)
         $this->newLine(2 - substr_count($chars, "\n"));
     }
 
-    private function autoPrependText()
+    private function autoPrependText(): void
     {
         $fetched = $this->bufferedOutput->fetch();
         //Prepend new line if last char isn't EOL:
@@ -376,7 +375,7 @@ private function autoPrependText()
         }
     }
 
-    private function reduceBuffer($messages)
+    private function reduceBuffer($messages): array
     {
         // We need to know if the two last chars are PHP_EOL
         // Preserve the last 4 chars inserted (PHP_EOL on windows is two chars) in the history buffer
@@ -385,7 +384,7 @@ private function reduceBuffer($messages)
         }, array_merge(array($this->bufferedOutput->fetch()), (array) $messages));
     }
 
-    private function createBlock($messages, $type = null, $style = null, $prefix = ' ', $padding = false, $escape = false)
+    private function createBlock(iterable $messages, string $type = null, string $style = null, string $prefix = ' ', bool $padding = false, bool $escape = false)
     {
         $indentLength = 0;
         $prefixLength = Helper::strlenWithoutDecoration($this->getFormatter(), $prefix);
diff --git a/src/Symfony/Component/CssSelector/Node/AbstractNode.php b/src/Symfony/Component/CssSelector/Node/AbstractNode.php
index 7477e9119df32..123ef1b117a67 100644
--- a/src/Symfony/Component/CssSelector/Node/AbstractNode.php
+++ b/src/Symfony/Component/CssSelector/Node/AbstractNode.php
@@ -31,7 +31,7 @@ abstract class AbstractNode implements NodeInterface
     /**
      * @return string
      */
-    public function getNodeName()
+    public function getNodeName(): string
     {
         if (null === $this->nodeName) {
             $this->nodeName = preg_replace('~.*\\\\([^\\\\]+)Node$~', '$1', get_called_class());
diff --git a/src/Symfony/Component/CssSelector/Node/AttributeNode.php b/src/Symfony/Component/CssSelector/Node/AttributeNode.php
index af872b79e9f2d..0db22c009589b 100644
--- a/src/Symfony/Component/CssSelector/Node/AttributeNode.php
+++ b/src/Symfony/Component/CssSelector/Node/AttributeNode.php
@@ -107,7 +107,7 @@ public function getValue()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->selector->getSpecificity()->plus(new Specificity(0, 1, 0));
     }
@@ -115,7 +115,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         $attribute = $this->namespace ? $this->namespace.'|'.$this->attribute : $this->attribute;
 
diff --git a/src/Symfony/Component/CssSelector/Node/ClassNode.php b/src/Symfony/Component/CssSelector/Node/ClassNode.php
index f965e7773e89a..f036c41c157be 100644
--- a/src/Symfony/Component/CssSelector/Node/ClassNode.php
+++ b/src/Symfony/Component/CssSelector/Node/ClassNode.php
@@ -62,7 +62,7 @@ public function getName()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->selector->getSpecificity()->plus(new Specificity(0, 1, 0));
     }
@@ -70,7 +70,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         return sprintf('%s[%s.%s]', $this->getNodeName(), $this->selector, $this->name);
     }
diff --git a/src/Symfony/Component/CssSelector/Node/CombinedSelectorNode.php b/src/Symfony/Component/CssSelector/Node/CombinedSelectorNode.php
index 39f659977779c..97a122cb2ae82 100644
--- a/src/Symfony/Component/CssSelector/Node/CombinedSelectorNode.php
+++ b/src/Symfony/Component/CssSelector/Node/CombinedSelectorNode.php
@@ -77,7 +77,7 @@ public function getSubSelector()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->selector->getSpecificity()->plus($this->subSelector->getSpecificity());
     }
@@ -85,7 +85,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         $combinator = ' ' === $this->combinator ? '<followed>' : $this->combinator;
 
diff --git a/src/Symfony/Component/CssSelector/Node/ElementNode.php b/src/Symfony/Component/CssSelector/Node/ElementNode.php
index 06e343e969c11..5b57a3a4f08a2 100644
--- a/src/Symfony/Component/CssSelector/Node/ElementNode.php
+++ b/src/Symfony/Component/CssSelector/Node/ElementNode.php
@@ -62,7 +62,7 @@ public function getElement()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return new Specificity(0, 0, $this->element ? 1 : 0);
     }
@@ -70,7 +70,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         $element = $this->element ?: '*';
 
diff --git a/src/Symfony/Component/CssSelector/Node/FunctionNode.php b/src/Symfony/Component/CssSelector/Node/FunctionNode.php
index 612f348c5e419..ba2434c062816 100644
--- a/src/Symfony/Component/CssSelector/Node/FunctionNode.php
+++ b/src/Symfony/Component/CssSelector/Node/FunctionNode.php
@@ -79,7 +79,7 @@ public function getArguments()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->selector->getSpecificity()->plus(new Specificity(0, 1, 0));
     }
@@ -87,7 +87,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         $arguments = implode(', ', array_map(function (Token $token) {
             return "'".$token->getValue()."'";
diff --git a/src/Symfony/Component/CssSelector/Node/HashNode.php b/src/Symfony/Component/CssSelector/Node/HashNode.php
index 20db465162806..50e6d09ff7def 100644
--- a/src/Symfony/Component/CssSelector/Node/HashNode.php
+++ b/src/Symfony/Component/CssSelector/Node/HashNode.php
@@ -62,7 +62,7 @@ public function getId()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->selector->getSpecificity()->plus(new Specificity(1, 0, 0));
     }
@@ -70,7 +70,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         return sprintf('%s[%s#%s]', $this->getNodeName(), $this->selector, $this->id);
     }
diff --git a/src/Symfony/Component/CssSelector/Node/NegationNode.php b/src/Symfony/Component/CssSelector/Node/NegationNode.php
index 4b5aa2260d005..e481b52861a57 100644
--- a/src/Symfony/Component/CssSelector/Node/NegationNode.php
+++ b/src/Symfony/Component/CssSelector/Node/NegationNode.php
@@ -62,7 +62,7 @@ public function getSubSelector()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->selector->getSpecificity()->plus($this->subSelector->getSpecificity());
     }
@@ -70,7 +70,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         return sprintf('%s[%s:not(%s)]', $this->getNodeName(), $this->selector, $this->subSelector);
     }
diff --git a/src/Symfony/Component/CssSelector/Node/NodeInterface.php b/src/Symfony/Component/CssSelector/Node/NodeInterface.php
index d919e20c7107a..b078d26d4de31 100644
--- a/src/Symfony/Component/CssSelector/Node/NodeInterface.php
+++ b/src/Symfony/Component/CssSelector/Node/NodeInterface.php
@@ -23,24 +23,9 @@
  */
 interface NodeInterface
 {
-    /**
-     * Returns node's name.
-     *
-     * @return string
-     */
-    public function getNodeName();
+    public function getNodeName(): string;
 
-    /**
-     * Returns node's specificity.
-     *
-     * @return Specificity
-     */
-    public function getSpecificity();
+    public function getSpecificity(): Specificity;
 
-    /**
-     * Returns node's string representation.
-     *
-     * @return string
-     */
-    public function __toString();
+    public function __toString(): string;
 }
diff --git a/src/Symfony/Component/CssSelector/Node/PseudoNode.php b/src/Symfony/Component/CssSelector/Node/PseudoNode.php
index c23ddd5912a66..25aa9e2b2799f 100644
--- a/src/Symfony/Component/CssSelector/Node/PseudoNode.php
+++ b/src/Symfony/Component/CssSelector/Node/PseudoNode.php
@@ -62,7 +62,7 @@ public function getIdentifier()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->selector->getSpecificity()->plus(new Specificity(0, 1, 0));
     }
@@ -70,7 +70,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         return sprintf('%s[%s:%s]', $this->getNodeName(), $this->selector, $this->identifier);
     }
diff --git a/src/Symfony/Component/CssSelector/Node/SelectorNode.php b/src/Symfony/Component/CssSelector/Node/SelectorNode.php
index 729e0911b3c76..34c323b17cf6d 100644
--- a/src/Symfony/Component/CssSelector/Node/SelectorNode.php
+++ b/src/Symfony/Component/CssSelector/Node/SelectorNode.php
@@ -62,7 +62,7 @@ public function getPseudoElement()
     /**
      * {@inheritdoc}
      */
-    public function getSpecificity()
+    public function getSpecificity(): Specificity
     {
         return $this->tree->getSpecificity()->plus(new Specificity(0, 0, $this->pseudoElement ? 1 : 0));
     }
@@ -70,7 +70,7 @@ public function getSpecificity()
     /**
      * {@inheritdoc}
      */
-    public function __toString()
+    public function __toString(): string
     {
         return sprintf('%s[%s%s]', $this->getNodeName(), $this->tree, $this->pseudoElement ? '::'.$this->pseudoElement : '');
     }
diff --git a/src/Symfony/Component/CssSelector/Node/Specificity.php b/src/Symfony/Component/CssSelector/Node/Specificity.php
index d09eaca77ef45..be8a0e01144cf 100644
--- a/src/Symfony/Component/CssSelector/Node/Specificity.php
+++ b/src/Symfony/Component/CssSelector/Node/Specificity.php
@@ -44,36 +44,19 @@ class Specificity
      */
     private $c;
 
-    /**
-     * Constructor.
-     *
-     * @param int $a
-     * @param int $b
-     * @param int $c
-     */
-    public function __construct($a, $b, $c)
+    public function __construct(int $a, int $b, int $c)
     {
         $this->a = $a;
         $this->b = $b;
         $this->c = $c;
     }
 
-    /**
-     * @param Specificity $specificity
-     *
-     * @return self
-     */
-    public function plus(Specificity $specificity)
+    public function plus(Specificity $specificity): Specificity
     {
         return new self($this->a + $specificity->a, $this->b + $specificity->b, $this->c + $specificity->c);
     }
 
-    /**
-     * Returns global specificity value.
-     *
-     * @return int
-     */
-    public function getValue()
+    public function getValue(): int
     {
         return $this->a * self::A_FACTOR + $this->b * self::B_FACTOR + $this->c * self::C_FACTOR;
     }
diff --git a/src/Symfony/Component/CssSelector/Parser/Handler/CommentHandler.php b/src/Symfony/Component/CssSelector/Parser/Handler/CommentHandler.php
index a29775cab370f..93f318844a5bd 100644
--- a/src/Symfony/Component/CssSelector/Parser/Handler/CommentHandler.php
+++ b/src/Symfony/Component/CssSelector/Parser/Handler/CommentHandler.php
@@ -29,7 +29,7 @@ class CommentHandler implements HandlerInterface
     /**
      * {@inheritdoc}
      */
-    public function handle(Reader $reader, TokenStream $stream)
+    public function handle(Reader $reader, TokenStream $stream): bool
     {
         if ('/*' !== $reader->getSubstring(2)) {
             return false;
diff --git a/src/Symfony/Component/CssSelector/Parser/Handler/HandlerInterface.php b/src/Symfony/Component/CssSelector/Parser/Handler/HandlerInterface.php
index a1297c80c089b..10e20ac711cdb 100644
--- a/src/Symfony/Component/CssSelector/Parser/Handler/HandlerInterface.php
+++ b/src/Symfony/Component/CssSelector/Parser/Handler/HandlerInterface.php
@@ -32,5 +32,5 @@ interface HandlerInterface
      *
      * @return bool
      */
-    public function handle(Reader $reader, TokenStream $stream);
+    public function handle(Reader $reader, TokenStream $stream): bool;
 }
diff --git a/src/Symfony/Component/CssSelector/Parser/Handler/HashHandler.php b/src/Symfony/Component/CssSelector/Parser/Handler/HashHandler.php
index f74bda51262ac..145fe5925f384 100644
--- a/src/Symfony/Component/CssSelector/Parser/Handler/HashHandler.php
+++ b/src/Symfony/Component/CssSelector/Parser/Handler/HashHandler.php
@@ -52,7 +52,7 @@ public function __construct(TokenizerPatterns $patterns, TokenizerEscaping $esca
     /**
      * {@inheritdoc}
      */
-    public function handle(Reader $reader, TokenStream $stream)
+    public function handle(Reader $reader, TokenStream $stream): bool
     {
         $match = $reader->findPattern($this->patterns->getHashPattern());
 
diff --git a/src/Symfony/Component/CssSelector/Parser/Handler/IdentifierHandler.php b/src/Symfony/Component/CssSelector/Parser/Handler/IdentifierHandler.php
index 358c7c14ad28a..704f939d618e2 100644
--- a/src/Symfony/Component/CssSelector/Parser/Handler/IdentifierHandler.php
+++ b/src/Symfony/Component/CssSelector/Parser/Handler/IdentifierHandler.php
@@ -52,7 +52,7 @@ public function __construct(TokenizerPatterns $patterns, TokenizerEscaping $esca
     /**
      * {@inheritdoc}
      */
-    public function handle(Reader $reader, TokenStream $stream)
+    public function handle(Reader $reader, TokenStream $stream): bool
     {
         $match = $reader->findPattern($this->patterns->getIdentifierPattern());
 
diff --git a/src/Symfony/Component/CssSelector/Parser/Handler/NumberHandler.php b/src/Symfony/Component/CssSelector/Parser/Handler/NumberHandler.php
index 4ea5c484b26fb..7ef2fe3171ce2 100644
--- a/src/Symfony/Component/CssSelector/Parser/Handler/NumberHandler.php
+++ b/src/Symfony/Component/CssSelector/Parser/Handler/NumberHandler.php
@@ -44,7 +44,7 @@ public function __construct(TokenizerPatterns $patterns)
     /**
      * {@inheritdoc}
      */
-    public function handle(Reader $reader, TokenStream $stream)
+    public function handle(Reader $reader, TokenStream $stream): bool
     {
         $match = $reader->findPattern($this->patterns->getNumberPattern());
 
diff --git a/src/Symfony/Component/CssSelector/Parser/Handler/StringHandler.php b/src/Symfony/Component/CssSelector/Parser/Handler/StringHandler.php
index 420529601609d..18a88acbc3146 100644
--- a/src/Symfony/Component/CssSelector/Parser/Handler/StringHandler.php
+++ b/src/Symfony/Component/CssSelector/Parser/Handler/StringHandler.php
@@ -54,7 +54,7 @@ public function __construct(TokenizerPatterns $patterns, TokenizerEscaping $esca
     /**
      * {@inheritdoc}
      */
-    public function handle(Reader $reader, TokenStream $stream)
+    public function handle(Reader $reader, TokenStream $stream): bool
     {
         $quote = $reader->getSubstring(1);
 
diff --git a/src/Symfony/Component/CssSelector/Parser/Handler/WhitespaceHandler.php b/src/Symfony/Component/CssSelector/Parser/Handler/WhitespaceHandler.php
index 4c2d3354fb83e..ebf8a19fe2605 100644
--- a/src/Symfony/Component/CssSelector/Parser/Handler/WhitespaceHandler.php
+++ b/src/Symfony/Component/CssSelector/Parser/Handler/WhitespaceHandler.php
@@ -30,7 +30,7 @@ class WhitespaceHandler implements HandlerInterface
     /**
      * {@inheritdoc}
      */
-    public function handle(Reader $reader, TokenStream $stream)
+    public function handle(Reader $reader, TokenStream $stream): bool
     {
         $match = $reader->findPattern('~^[ \t\r\n\f]+~');
 
diff --git a/src/Symfony/Component/CssSelector/Parser/Parser.php b/src/Symfony/Component/CssSelector/Parser/Parser.php
index 3c5b2dd264b50..aefb84386dddb 100644
--- a/src/Symfony/Component/CssSelector/Parser/Parser.php
+++ b/src/Symfony/Component/CssSelector/Parser/Parser.php
@@ -45,7 +45,7 @@ public function __construct(Tokenizer $tokenizer = null)
     /**
      * {@inheritdoc}
      */
-    public function parse($source)
+    public function parse(string $source): array
     {
         $reader = new Reader($source);
         $stream = $this->tokenizer->tokenize($reader);
@@ -102,14 +102,7 @@ public static function parseSeries(array $tokens)
         );
     }
 
-    /**
-     * Parses selector nodes.
-     *
-     * @param TokenStream $stream
-     *
-     * @return array
-     */
-    private function parseSelectorList(TokenStream $stream)
+    private function parseSelectorList(TokenStream $stream): array
     {
         $stream->skipWhitespace();
         $selectors = array();
@@ -128,16 +121,7 @@ private function parseSelectorList(TokenStream $stream)
         return $selectors;
     }
 
-    /**
-     * Parses next selector or combined node.
-     *
-     * @param TokenStream $stream
-     *
-     * @return Node\SelectorNode
-     *
-     * @throws SyntaxErrorException
-     */
-    private function parserSelectorNode(TokenStream $stream)
+    private function parserSelectorNode(TokenStream $stream): Node\SelectorNode
     {
         list($result, $pseudoElement) = $this->parseSimpleSelector($stream);
 
@@ -291,14 +275,7 @@ private function parseSimpleSelector(TokenStream $stream, $insideNegation = fals
         return array($result, $pseudoElement);
     }
 
-    /**
-     * Parses next element node.
-     *
-     * @param TokenStream $stream
-     *
-     * @return Node\ElementNode
-     */
-    private function parseElementNode(TokenStream $stream)
+    private function parseElementNode(TokenStream $stream): Node\ElementNode
     {
         $peek = $stream->getPeek();
 
@@ -324,17 +301,7 @@ private function parseElementNode(TokenStream $stream)
         return new Node\ElementNode($namespace, $element);
     }
 
-    /**
-     * Parses next attribute node.
-     *
-     * @param Node\NodeInterface $selector
-     * @param TokenStream        $stream
-     *
-     * @return Node\AttributeNode
-     *
-     * @throws SyntaxErrorException
-     */
-    private function parseAttributeNode(Node\NodeInterface $selector, TokenStream $stream)
+    private function parseAttributeNode(Node\NodeInterface $selector, TokenStream $stream): Node\AttributeNode
     {
         $stream->skipWhitespace();
         $attribute = $stream->getNextIdentifierOrStar();
diff --git a/src/Symfony/Component/CssSelector/Parser/ParserInterface.php b/src/Symfony/Component/CssSelector/Parser/ParserInterface.php
index c5af20367de8c..88c8879e0b6e8 100644
--- a/src/Symfony/Component/CssSelector/Parser/ParserInterface.php
+++ b/src/Symfony/Component/CssSelector/Parser/ParserInterface.php
@@ -32,5 +32,5 @@ interface ParserInterface
      *
      * @return SelectorNode[]
      */
-    public function parse($source);
+    public function parse(string $source): array;
 }
diff --git a/src/Symfony/Component/CssSelector/Parser/Shortcut/ClassParser.php b/src/Symfony/Component/CssSelector/Parser/Shortcut/ClassParser.php
index c513de5ff12ee..ce7b20ef2e768 100644
--- a/src/Symfony/Component/CssSelector/Parser/Shortcut/ClassParser.php
+++ b/src/Symfony/Component/CssSelector/Parser/Shortcut/ClassParser.php
@@ -31,7 +31,7 @@ class ClassParser implements ParserInterface
     /**
      * {@inheritdoc}
      */
-    public function parse($source)
+    public function parse(string $source): array
     {
         // Matches an optional namespace, optional element, and required class
         // $source = 'test|input.ab6bd_field';
diff --git a/src/Symfony/Component/CssSelector/Parser/Shortcut/ElementParser.php b/src/Symfony/Component/CssSelector/Parser/Shortcut/ElementParser.php
index c29f5e442e739..3b93f0068f5d4 100644
--- a/src/Symfony/Component/CssSelector/Parser/Shortcut/ElementParser.php
+++ b/src/Symfony/Component/CssSelector/Parser/Shortcut/ElementParser.php
@@ -30,7 +30,7 @@ class ElementParser implements ParserInterface
     /**
      * {@inheritdoc}
      */
-    public function parse($source)
+    public function parse(string $source): array
     {
         // Matches an optional namespace, required element or `*`
         // $source = 'testns|testel';
diff --git a/src/Symfony/Component/CssSelector/Parser/Shortcut/EmptyStringParser.php b/src/Symfony/Component/CssSelector/Parser/Shortcut/EmptyStringParser.php
index 016cf0a848207..0c366cc4e0897 100644
--- a/src/Symfony/Component/CssSelector/Parser/Shortcut/EmptyStringParser.php
+++ b/src/Symfony/Component/CssSelector/Parser/Shortcut/EmptyStringParser.php
@@ -34,7 +34,7 @@ class EmptyStringParser implements ParserInterface
     /**
      * {@inheritdoc}
      */
-    public function parse($source)
+    public function parse(string $source): array
     {
         // Matches an empty string
         if ($source == '') {
diff --git a/src/Symfony/Component/CssSelector/Parser/Shortcut/HashParser.php b/src/Symfony/Component/CssSelector/Parser/Shortcut/HashParser.php
index 3f3883bb8d2e9..e94ce0a46afd4 100644
--- a/src/Symfony/Component/CssSelector/Parser/Shortcut/HashParser.php
+++ b/src/Symfony/Component/CssSelector/Parser/Shortcut/HashParser.php
@@ -31,7 +31,7 @@ class HashParser implements ParserInterface
     /**
      * {@inheritdoc}
      */
-    public function parse($source)
+    public function parse(string $source): array
     {
         // Matches an optional namespace, optional element, and required id
         // $source = 'test|input#ab6bd_field';
diff --git a/src/Symfony/Component/CssSelector/Parser/Token.php b/src/Symfony/Component/CssSelector/Parser/Token.php
index 68fac59b03a32..43cabb5e92cb2 100644
--- a/src/Symfony/Component/CssSelector/Parser/Token.php
+++ b/src/Symfony/Component/CssSelector/Parser/Token.php
@@ -47,7 +47,7 @@ class Token
     private $position;
 
     /**
-     * @param int    $type
+     * @param string $type
      * @param string $value
      * @param int    $position
      */
@@ -82,20 +82,12 @@ public function getPosition()
         return $this->position;
     }
 
-    /**
-     * @return bool
-     */
-    public function isFileEnd()
+    public function isFileEnd(): bool
     {
         return self::TYPE_FILE_END === $this->type;
     }
 
-    /**
-     * @param array $values
-     *
-     * @return bool
-     */
-    public function isDelimiter(array $values = array())
+    public function isDelimiter(array $values = array()): bool
     {
         if (self::TYPE_DELIMITER !== $this->type) {
             return false;
@@ -108,50 +100,32 @@ public function isDelimiter(array $values = array())
         return in_array($this->value, $values);
     }
 
-    /**
-     * @return bool
-     */
-    public function isWhitespace()
+    public function isWhitespace(): bool
     {
         return self::TYPE_WHITESPACE === $this->type;
     }
 
-    /**
-     * @return bool
-     */
-    public function isIdentifier()
+    public function isIdentifier(): bool
     {
         return self::TYPE_IDENTIFIER === $this->type;
     }
 
-    /**
-     * @return bool
-     */
-    public function isHash()
+    public function isHash(): bool
     {
         return self::TYPE_HASH === $this->type;
     }
 
-    /**
-     * @return bool
-     */
-    public function isNumber()
+    public function isNumber(): bool
     {
         return self::TYPE_NUMBER === $this->type;
     }
 
-    /**
-     * @return bool
-     */
-    public function isString()
+    public function isString(): bool
     {
         return self::TYPE_STRING === $this->type;
     }
 
-    /**
-     * @return string
-     */
-    public function __toString()
+    public function __toString(): string
     {
         if ($this->value) {
             return sprintf('<%s "%s" at %s>', $this->type, $this->value, $this->position);
diff --git a/src/Symfony/Component/CssSelector/Parser/Tokenizer/TokenizerEscaping.php b/src/Symfony/Component/CssSelector/Parser/Tokenizer/TokenizerEscaping.php
index af4c31e5b09b8..2ca10f3a13199 100644
--- a/src/Symfony/Component/CssSelector/Parser/Tokenizer/TokenizerEscaping.php
+++ b/src/Symfony/Component/CssSelector/Parser/Tokenizer/TokenizerEscaping.php
@@ -28,44 +28,26 @@ class TokenizerEscaping
      */
     private $patterns;
 
-    /**
-     * @param TokenizerPatterns $patterns
-     */
     public function __construct(TokenizerPatterns $patterns)
     {
         $this->patterns = $patterns;
     }
 
-    /**
-     * @param string $value
-     *
-     * @return string
-     */
-    public function escapeUnicode($value)
+    public function escapeUnicode(string $value): string
     {
         $value = $this->replaceUnicodeSequences($value);
 
         return preg_replace($this->patterns->getSimpleEscapePattern(), '$1', $value);
     }
 
-    /**
-     * @param string $value
-     *
-     * @return string
-     */
-    public function escapeUnicodeAndNewLine($value)
+    public function escapeUnicodeAndNewLine(string $value): string
     {
         $value = preg_replace($this->patterns->getNewLineEscapePattern(), '', $value);
 
         return $this->escapeUnicode($value);
     }
 
-    /**
-     * @param string $value
-     *
-     * @return string
-     */
-    private function replaceUnicodeSequences($value)
+    private function replaceUnicodeSequences(string $value): string
     {
         return preg_replace_callback($this->patterns->getUnicodeEscapePattern(), function ($match) {
             $c = hexdec($match[1]);
diff --git a/src/Symfony/Component/CssSelector/XPath/Extension/CombinationExtension.php b/src/Symfony/Component/CssSelector/XPath/Extension/CombinationExtension.php
index 0d2d658b65c64..a13ea32e5b71c 100644
--- a/src/Symfony/Component/CssSelector/XPath/Extension/CombinationExtension.php
+++ b/src/Symfony/Component/CssSelector/XPath/Extension/CombinationExtension.php
@@ -28,7 +28,7 @@ class CombinationExtension extends AbstractExtension
     /**
      * {@inheritdoc}
      */
-    public function getCombinationTranslators()
+    public function getCombinationTranslators(): array
     {
         return array(
             ' ' => array($this, 'translateDescendant'),
@@ -44,7 +44,7 @@ public function getCombinationTranslators()
      *
      * @return XPathExpr
      */
-    public function translateDescendant(XPathExpr $xpath, XPathExpr $combinedXpath)
+    public function translateDescendant(XPathExpr $xpath, XPathExpr $combinedXpath): XPathExpr
     {
         return $xpath->join('/descendant-or-self::*/', $combinedXpath);
     }
diff --git a/src/Symfony/Component/CssSelector/XPath/Translator.php b/src/Symfony/Component/CssSelector/XPath/Translator.php
index 2b01fc8e52526..4c43f3c9ebdfa 100644
--- a/src/Symfony/Component/CssSelector/XPath/Translator.php
+++ b/src/Symfony/Component/CssSelector/XPath/Translator.php
@@ -83,12 +83,7 @@ public function __construct(ParserInterface $parser = null)
         ;
     }
 
-    /**
-     * @param string $element
-     *
-     * @return string
-     */
-    public static function getXpathLiteral($element)
+    public static function getXpathLiteral(string $element): string
     {
         if (false === strpos($element, "'")) {
             return "'".$element."'";
@@ -117,7 +112,7 @@ public static function getXpathLiteral($element)
     /**
      * {@inheritdoc}
      */
-    public function cssToXPath($cssExpr, $prefix = 'descendant-or-self::')
+    public function cssToXPath(string $cssExpr, string $prefix = 'descendant-or-self::'): string
     {
         $selectors = $this->parseSelectors($cssExpr);
 
@@ -136,19 +131,12 @@ public function cssToXPath($cssExpr, $prefix = 'descendant-or-self::')
     /**
      * {@inheritdoc}
      */
-    public function selectorToXPath(SelectorNode $selector, $prefix = 'descendant-or-self::')
+    public function selectorToXPath(SelectorNode $selector, string $prefix = 'descendant-or-self::'): string
     {
         return ($prefix ?: '').$this->nodeToXPath($selector);
     }
 
-    /**
-     * Registers an extension.
-     *
-     * @param Extension\ExtensionInterface $extension
-     *
-     * @return $this
-     */
-    public function registerExtension(Extension\ExtensionInterface $extension)
+    public function registerExtension(Extension\ExtensionInterface $extension): Translator
     {
         $this->extensions[$extension->getName()] = $extension;
 
@@ -162,13 +150,9 @@ public function registerExtension(Extension\ExtensionInterface $extension)
     }
 
     /**
-     * @param string $name
-     *
-     * @return Extension\ExtensionInterface
-     *
      * @throws ExpressionErrorException
      */
-    public function getExtension($name)
+    public function getExtension(string $name): Extension\ExtensionInterface
     {
         if (!isset($this->extensions[$name])) {
             throw new ExpressionErrorException(sprintf('Extension "%s" not registered.', $name));
@@ -177,14 +161,7 @@ public function getExtension($name)
         return $this->extensions[$name];
     }
 
-    /**
-     * Registers a shortcut parser.
-     *
-     * @param ParserInterface $shortcut
-     *
-     * @return $this
-     */
-    public function registerParserShortcut(ParserInterface $shortcut)
+    public function registerParserShortcut(ParserInterface $shortcut): Translator
     {
         $this->shortcutParsers[] = $shortcut;
 
@@ -192,13 +169,9 @@ public function registerParserShortcut(ParserInterface $shortcut)
     }
 
     /**
-     * @param NodeInterface $node
-     *
-     * @return XPathExpr
-     *
      * @throws ExpressionErrorException
      */
-    public function nodeToXPath(NodeInterface $node)
+    public function nodeToXPath(NodeInterface $node): XPathExpr
     {
         if (!isset($this->nodeTranslators[$node->getNodeName()])) {
             throw new ExpressionErrorException(sprintf('Node "%s" not supported.', $node->getNodeName()));
@@ -208,15 +181,9 @@ public function nodeToXPath(NodeInterface $node)
     }
 
     /**
-     * @param string        $combiner
-     * @param NodeInterface $xpath
-     * @param NodeInterface $combinedXpath
-     *
-     * @return XPathExpr
-     *
      * @throws ExpressionErrorException
      */
-    public function addCombination($combiner, NodeInterface $xpath, NodeInterface $combinedXpath)
+    public function addCombination(string $combiner, NodeInterface $xpath, NodeInterface $combinedXpath): XPathExpr
     {
         if (!isset($this->combinationTranslators[$combiner])) {
             throw new ExpressionErrorException(sprintf('Combiner "%s" not supported.', $combiner));
@@ -226,14 +193,9 @@ public function addCombination($combiner, NodeInterface $xpath, NodeInterface $c
     }
 
     /**
-     * @param XPathExpr    $xpath
-     * @param FunctionNode $function
-     *
-     * @return XPathExpr
-     *
      * @throws ExpressionErrorException
      */
-    public function addFunction(XPathExpr $xpath, FunctionNode $function)
+    public function addFunction(XPathExpr $xpath, FunctionNode $function): XPathExpr
     {
         if (!isset($this->functionTranslators[$function->getName()])) {
             throw new ExpressionErrorException(sprintf('Function "%s" not supported.', $function->getName()));
@@ -243,14 +205,9 @@ public function addFunction(XPathExpr $xpath, FunctionNode $function)
     }
 
     /**
-     * @param XPathExpr $xpath
-     * @param string    $pseudoClass
-     *
-     * @return XPathExpr
-     *
      * @throws ExpressionErrorException
      */
-    public function addPseudoClass(XPathExpr $xpath, $pseudoClass)
+    public function addPseudoClass(XPathExpr $xpath, string $pseudoClass): XPathExpr
     {
         if (!isset($this->pseudoClassTranslators[$pseudoClass])) {
             throw new ExpressionErrorException(sprintf('Pseudo-class "%s" not supported.', $pseudoClass));
@@ -260,16 +217,9 @@ public function addPseudoClass(XPathExpr $xpath, $pseudoClass)
     }
 
     /**
-     * @param XPathExpr $xpath
-     * @param string    $operator
-     * @param string    $attribute
-     * @param string    $value
-     *
-     * @return XPathExpr
-     *
      * @throws ExpressionErrorException
      */
-    public function addAttributeMatching(XPathExpr $xpath, $operator, $attribute, $value)
+    public function addAttributeMatching(XPathExpr $xpath, string $operator, string $attribute, $value): XPathExpr
     {
         if (!isset($this->attributeMatchingTranslators[$operator])) {
             throw new ExpressionErrorException(sprintf('Attribute matcher operator "%s" not supported.', $operator));
diff --git a/src/Symfony/Component/CssSelector/XPath/TranslatorInterface.php b/src/Symfony/Component/CssSelector/XPath/TranslatorInterface.php
index 0b5de83d57124..3224859559470 100644
--- a/src/Symfony/Component/CssSelector/XPath/TranslatorInterface.php
+++ b/src/Symfony/Component/CssSelector/XPath/TranslatorInterface.php
@@ -33,7 +33,7 @@ interface TranslatorInterface
      *
      * @return string
      */
-    public function cssToXPath($cssExpr, $prefix = 'descendant-or-self::');
+    public function cssToXPath(string $cssExpr, string $prefix = 'descendant-or-self::'): string;
 
     /**
      * Translates a parsed selector node to an XPath expression.
@@ -43,5 +43,5 @@ public function cssToXPath($cssExpr, $prefix = 'descendant-or-self::');
      *
      * @return string
      */
-    public function selectorToXPath(SelectorNode $selector, $prefix = 'descendant-or-self::');
+    public function selectorToXPath(SelectorNode $selector, string $prefix = 'descendant-or-self::'): string;
 }
diff --git a/src/Symfony/Component/CssSelector/XPath/XPathExpr.php b/src/Symfony/Component/CssSelector/XPath/XPathExpr.php
index 38ca295540071..093cfaf32f967 100644
--- a/src/Symfony/Component/CssSelector/XPath/XPathExpr.php
+++ b/src/Symfony/Component/CssSelector/XPath/XPathExpr.php
@@ -38,13 +38,7 @@ class XPathExpr
      */
     private $condition;
 
-    /**
-     * @param string $path
-     * @param string $element
-     * @param string $condition
-     * @param bool   $starPrefix
-     */
-    public function __construct($path = '', $element = '*', $condition = '', $starPrefix = false)
+    public function __construct(string $path = '', string $element = '*', string $condition = '', bool $starPrefix = false)
     {
         $this->path = $path;
         $this->element = $element;
@@ -55,20 +49,12 @@ public function __construct($path = '', $element = '*', $condition = '', $starPr
         }
     }
 
-    /**
-     * @return string
-     */
-    public function getElement()
+    public function getElement(): string
     {
         return $this->element;
     }
 
-    /**
-     * @param $condition
-     *
-     * @return $this
-     */
-    public function addCondition($condition)
+    public function addCondition(string $condition): XPathExpr
     {
         $this->condition = $this->condition ? sprintf('%s and (%s)', $this->condition, $condition) : $condition;
 
@@ -78,15 +64,12 @@ public function addCondition($condition)
     /**
      * @return string
      */
-    public function getCondition()
+    public function getCondition(): string
     {
         return $this->condition;
     }
 
-    /**
-     * @return $this
-     */
-    public function addNameTest()
+    public function addNameTest(): XPathExpr
     {
         if ('*' !== $this->element) {
             $this->addCondition('name() = '.Translator::getXpathLiteral($this->element));
@@ -96,10 +79,7 @@ public function addNameTest()
         return $this;
     }
 
-    /**
-     * @return $this
-     */
-    public function addStarPrefix()
+    public function addStarPrefix(): XPathExpr
     {
         $this->path .= '*/';
 
@@ -114,7 +94,7 @@ public function addStarPrefix()
      *
      * @return $this
      */
-    public function join($combiner, XPathExpr $expr)
+    public function join(string $combiner, XPathExpr $expr): XPathExpr
     {
         $path = $this->__toString().$combiner;
 
@@ -129,10 +109,7 @@ public function join($combiner, XPathExpr $expr)
         return $this;
     }
 
-    /**
-     * @return string
-     */
-    public function __toString()
+    public function __toString(): string
     {
         $path = $this->path.$this->element;
         $condition = null === $this->condition || '' === $this->condition ? '' : '['.$this->condition.']';
diff --git a/src/Symfony/Component/Dotenv/Dotenv.php b/src/Symfony/Component/Dotenv/Dotenv.php
index 630e6f79c7043..c5f28d6e697fc 100644
--- a/src/Symfony/Component/Dotenv/Dotenv.php
+++ b/src/Symfony/Component/Dotenv/Dotenv.php
@@ -45,7 +45,7 @@ final class Dotenv
      * @throws FormatException when a file has a syntax error
      * @throws PathException   when a file does not exist or is not readable
      */
-    public function load($path, ...$paths)
+    public function load(string $path, string ...$paths): void
     {
         array_unshift($paths, $path);
 
@@ -65,7 +65,7 @@ public function load($path, ...$paths)
      *
      * @param array $values An array of env variables
      */
-    public function populate($values)
+    public function populate(array $values): void
     {
         $loadedVars = array_flip(explode(',', getenv('SYMFONY_DOTENV_VARS')));
         unset($loadedVars['']);
@@ -104,7 +104,7 @@ public function populate($values)
      *
      * @throws FormatException when a file has a syntax error
      */
-    public function parse($data, $path = '.env')
+    public function parse(string $data, string $path = '.env'): array
     {
         $this->path = $path;
         $this->data = str_replace(array("\r\n", "\r"), "\n", $data);
diff --git a/src/Symfony/Component/ExpressionLanguage/ExpressionLanguage.php b/src/Symfony/Component/ExpressionLanguage/ExpressionLanguage.php
index 64f4dd17371d5..c011b0c27058e 100644
--- a/src/Symfony/Component/ExpressionLanguage/ExpressionLanguage.php
+++ b/src/Symfony/Component/ExpressionLanguage/ExpressionLanguage.php
@@ -141,7 +141,7 @@ protected function registerFunctions()
         $this->addFunction(ExpressionFunction::fromPhp('constant'));
     }
 
-    private function getLexer()
+    private function getLexer(): Lexer
     {
         if (null === $this->lexer) {
             $this->lexer = new Lexer();
@@ -150,7 +150,7 @@ private function getLexer()
         return $this->lexer;
     }
 
-    private function getParser()
+    private function getParser(): Parser
     {
         if (null === $this->parser) {
             $this->parser = new Parser($this->functions);
@@ -159,7 +159,7 @@ private function getParser()
         return $this->parser;
     }
 
-    private function getCompiler()
+    private function getCompiler(): Compiler
     {
         if (null === $this->compiler) {
             $this->compiler = new Compiler($this->functions);
diff --git a/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php b/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php
index 583103217a626..4a18e83a5d0b9 100644
--- a/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php
+++ b/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php
@@ -27,7 +27,7 @@ class UnaryNode extends Node
         '-' => '-',
     );
 
-    public function __construct($operator, Node $node)
+    public function __construct(string $operator, Node $node)
     {
         parent::__construct(
             array('node' => $node),
@@ -59,7 +59,7 @@ public function evaluate($functions, $values)
         return $value;
     }
 
-    public function toArray()
+    public function toArray(): array
     {
         return array('(', $this->attributes['operator'].' ', $this->nodes['node'], ')');
     }
diff --git a/src/Symfony/Component/Form/Forms.php b/src/Symfony/Component/Form/Forms.php
index e84fcd0ab0048..061e98e170589 100644
--- a/src/Symfony/Component/Form/Forms.php
+++ b/src/Symfony/Component/Form/Forms.php
@@ -105,7 +105,7 @@ final class Forms
      *
      * @return FormFactoryInterface The form factory
      */
-    public static function createFormFactory()
+    public static function createFormFactory(): FormFactoryInterface
     {
         return self::createFormFactoryBuilder()->getFormFactory();
     }
@@ -115,7 +115,7 @@ public static function createFormFactory()
      *
      * @return FormFactoryBuilderInterface The form factory builder
      */
-    public static function createFormFactoryBuilder()
+    public static function createFormFactoryBuilder(): FormFactoryBuilderInterface
     {
         $builder = new FormFactoryBuilder();
         $builder->addExtension(new CoreExtension());
diff --git a/src/Symfony/Component/HttpKernel/Controller/ArgumentResolver.php b/src/Symfony/Component/HttpKernel/Controller/ArgumentResolver.php
index 2c17125c5aca1..186007ebe49c9 100644
--- a/src/Symfony/Component/HttpKernel/Controller/ArgumentResolver.php
+++ b/src/Symfony/Component/HttpKernel/Controller/ArgumentResolver.php
@@ -34,7 +34,7 @@ final class ArgumentResolver implements ArgumentResolverInterface
      */
     private $argumentValueResolvers;
 
-    public function __construct(ArgumentMetadataFactoryInterface $argumentMetadataFactory = null, $argumentValueResolvers = array())
+    public function __construct(ArgumentMetadataFactoryInterface $argumentMetadataFactory = null, iterable $argumentValueResolvers = array())
     {
         $this->argumentMetadataFactory = $argumentMetadataFactory ?: new ArgumentMetadataFactory();
         $this->argumentValueResolvers = $argumentValueResolvers ?: self::getDefaultArgumentValueResolvers();
@@ -81,7 +81,7 @@ public function getArguments(Request $request, $controller)
         return $arguments;
     }
 
-    public static function getDefaultArgumentValueResolvers()
+    public static function getDefaultArgumentValueResolvers(): iterable
     {
         return array(
             new RequestAttributeValueResolver(),
diff --git a/src/Symfony/Component/HttpKernel/Fragment/AbstractSurrogateFragmentRenderer.php b/src/Symfony/Component/HttpKernel/Fragment/AbstractSurrogateFragmentRenderer.php
index 07ab304e93ef1..74a0a7ca69981 100644
--- a/src/Symfony/Component/HttpKernel/Fragment/AbstractSurrogateFragmentRenderer.php
+++ b/src/Symfony/Component/HttpKernel/Fragment/AbstractSurrogateFragmentRenderer.php
@@ -85,7 +85,7 @@ public function render($uri, Request $request, array $options = array())
         return new Response($tag);
     }
 
-    private function generateSignedFragmentUri($uri, Request $request)
+    private function generateSignedFragmentUri($uri, Request $request): string
     {
         if (null === $this->signer) {
             throw new \LogicException('You must use a URI when using the ESI rendering strategy or set a URL signer.');
@@ -97,7 +97,7 @@ private function generateSignedFragmentUri($uri, Request $request)
         return substr($fragmentUri, strlen($request->getSchemeAndHttpHost()));
     }
 
-    private function containsNonScalars(array $values)
+    private function containsNonScalars(array $values): bool
     {
         foreach ($values as $value) {
             if (is_array($value) && $this->containsNonScalars($value)) {
diff --git a/src/Symfony/Component/HttpKernel/Fragment/HIncludeFragmentRenderer.php b/src/Symfony/Component/HttpKernel/Fragment/HIncludeFragmentRenderer.php
index ec2a40716ab72..632da8f8a565f 100644
--- a/src/Symfony/Component/HttpKernel/Fragment/HIncludeFragmentRenderer.php
+++ b/src/Symfony/Component/HttpKernel/Fragment/HIncludeFragmentRenderer.php
@@ -123,12 +123,7 @@ public function render($uri, Request $request, array $options = array())
         return new Response(sprintf('<hx:include src="%s"%s>%s</hx:include>', $uri, $renderedAttributes, $content));
     }
 
-    /**
-     * @param string $template
-     *
-     * @return bool
-     */
-    private function templateExists($template)
+    private function templateExists(string $template): bool
     {
         if ($this->templating instanceof EngineInterface) {
             try {
diff --git a/src/Symfony/Component/HttpKernel/HttpKernel.php b/src/Symfony/Component/HttpKernel/HttpKernel.php
index 4a35a9990b761..394147fc3fdc5 100644
--- a/src/Symfony/Component/HttpKernel/HttpKernel.php
+++ b/src/Symfony/Component/HttpKernel/HttpKernel.php
@@ -118,7 +118,7 @@ public function terminateWithException(\Exception $exception)
      * @throws \LogicException       If one of the listener does not behave as expected
      * @throws NotFoundHttpException When controller cannot be found
      */
-    private function handleRaw(Request $request, $type = self::MASTER_REQUEST)
+    private function handleRaw(Request $request, int $type = self::MASTER_REQUEST)
     {
         $this->requestStack->push($request);
 
@@ -184,7 +184,7 @@ private function handleRaw(Request $request, $type = self::MASTER_REQUEST)
      *
      * @throws \RuntimeException if the passed object is not a Response instance
      */
-    private function filterResponse(Response $response, Request $request, $type)
+    private function filterResponse(Response $response, Request $request, int $type)
     {
         $event = new FilterResponseEvent($this, $request, $type, $response);
 
@@ -205,7 +205,7 @@ private function filterResponse(Response $response, Request $request, $type)
      * @param Request $request
      * @param int     $type
      */
-    private function finishRequest(Request $request, $type)
+    private function finishRequest(Request $request, int $type)
     {
         $this->dispatcher->dispatch(KernelEvents::FINISH_REQUEST, new FinishRequestEvent($this, $request, $type));
         $this->requestStack->pop();
@@ -222,7 +222,7 @@ private function finishRequest(Request $request, $type)
      *
      * @throws \Exception
      */
-    private function handleException(\Exception $e, $request, $type)
+    private function handleException(\Exception $e, Request $request, int $type)
     {
         $event = new GetResponseForExceptionEvent($this, $request, $type, $e);
         $this->dispatcher->dispatch(KernelEvents::EXCEPTION, $event);
@@ -257,7 +257,7 @@ private function handleException(\Exception $e, $request, $type)
         }
     }
 
-    private function varToString($var)
+    private function varToString($var): string
     {
         if (is_object($var)) {
             return sprintf('Object(%s)', get_class($var));
diff --git a/src/Symfony/Component/Inflector/Inflector.php b/src/Symfony/Component/Inflector/Inflector.php
index fbe8cc8a45c72..cf685159a7f41 100644
--- a/src/Symfony/Component/Inflector/Inflector.php
+++ b/src/Symfony/Component/Inflector/Inflector.php
@@ -91,7 +91,7 @@ final class Inflector
         // accesses (access), addresses (address), kisses (kiss)
         array('sess', 4, true, false, 'ss'),
 
-        // analyses (analysis), ellipses (ellipsis), funguses (fungus),
+        // analyses (analysis), ellipses (ellipsis), fungi (fungus),
         // neuroses (neurosis), theses (thesis), emphases (emphasis),
         // oases (oasis), crises (crisis), houses (house), bases (base),
         // atlases (atlas)
@@ -159,7 +159,7 @@ private function __construct()
      *
      * @internal
      */
-    public static function singularize($plural)
+    public static function singularize(string $plural)
     {
         $pluralRev = strrev($plural);
         $lowerPluralRev = strtolower($pluralRev);
diff --git a/src/Symfony/Component/Intl/Data/Provider/LanguageDataProvider.php b/src/Symfony/Component/Intl/Data/Provider/LanguageDataProvider.php
index b601c91405b2c..c9256ccc58a8a 100644
--- a/src/Symfony/Component/Intl/Data/Provider/LanguageDataProvider.php
+++ b/src/Symfony/Component/Intl/Data/Provider/LanguageDataProvider.php
@@ -41,7 +41,7 @@ class LanguageDataProvider
      * @param BundleEntryReaderInterface $reader The reader for reading the .res
      *                                           files.
      */
-    public function __construct($path, BundleEntryReaderInterface $reader)
+    public function __construct(string $path, BundleEntryReaderInterface $reader)
     {
         $this->path = $path;
         $this->reader = $reader;
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php
index 66376475c666b..69d8a03a3aa9f 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php
@@ -23,7 +23,7 @@ class AmPmTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         return $dateTime->format('A');
     }
@@ -31,7 +31,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return 'AM|PM';
     }
@@ -39,7 +39,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'marker' => $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php
index a174fdcabc570..0bbc5cb44f47d 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php
@@ -23,7 +23,7 @@ class DayOfWeekTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $dayOfWeek = $dateTime->format('l');
         switch ($length) {
@@ -41,7 +41,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         switch ($length) {
             case 4:
@@ -58,7 +58,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array();
     }
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php
index 5af6dd724336b..23000311c7eb0 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php
@@ -23,7 +23,7 @@ class DayOfYearTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $dayOfYear = $dateTime->format('z') + 1;
 
@@ -33,7 +33,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return '\d{'.$length.'}';
     }
@@ -41,7 +41,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array();
     }
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php
index f0ded907c33c5..f05157f40269e 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php
@@ -23,7 +23,7 @@ class DayTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         return $this->padLeft($dateTime->format('j'), $length);
     }
@@ -31,7 +31,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return 1 === $length ? '\d{1,2}' : '\d{'.$length.'}';
     }
@@ -39,7 +39,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'day' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php
index 948e3450443ef..dd3a1a8e71368 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php
@@ -23,7 +23,7 @@ class Hour1200Transformer extends HourTransformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $hourOfDay = $dateTime->format('g');
         $hourOfDay = '12' == $hourOfDay ? '0' : $hourOfDay;
@@ -34,7 +34,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function normalizeHour($hour, $marker = null)
+    public function normalizeHour(int $hour, string $marker = null): int
     {
         if ('PM' === $marker) {
             $hour += 12;
@@ -46,7 +46,7 @@ public function normalizeHour($hour, $marker = null)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return '\d{1,2}';
     }
@@ -54,7 +54,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'hour' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php
index 19c4d203abe09..63aea50498ec0 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php
@@ -23,7 +23,7 @@ class Hour1201Transformer extends HourTransformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         return $this->padLeft($dateTime->format('g'), $length);
     }
@@ -31,7 +31,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function normalizeHour($hour, $marker = null)
+    public function normalizeHour(int $hour, string $marker = null): int
     {
         if ('PM' !== $marker && 12 === $hour) {
             $hour = 0;
@@ -46,7 +46,7 @@ public function normalizeHour($hour, $marker = null)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return '\d{1,2}';
     }
@@ -54,7 +54,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'hour' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php
index e43d0ee8b2aec..78233f3d3806d 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php
@@ -23,7 +23,7 @@ class Hour2400Transformer extends HourTransformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         return $this->padLeft($dateTime->format('G'), $length);
     }
@@ -31,7 +31,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function normalizeHour($hour, $marker = null)
+    public function normalizeHour(int $hour, string $marker = null): int
     {
         if ('AM' == $marker) {
             $hour = 0;
@@ -45,7 +45,7 @@ public function normalizeHour($hour, $marker = null)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return '\d{1,2}';
     }
@@ -53,7 +53,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'hour' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php
index df4e671aaf02b..e82c04da95314 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php
@@ -23,7 +23,7 @@ class Hour2401Transformer extends HourTransformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $hourOfDay = $dateTime->format('G');
         $hourOfDay = ('0' == $hourOfDay) ? '24' : $hourOfDay;
@@ -34,7 +34,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function normalizeHour($hour, $marker = null)
+    public function normalizeHour(int $hour, string $marker = null): int
     {
         if ((null === $marker && 24 === $hour) || 'AM' == $marker) {
             $hour = 0;
@@ -48,7 +48,7 @@ public function normalizeHour($hour, $marker = null)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return '\d{1,2}';
     }
@@ -56,7 +56,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'hour' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php
index 349d8e29ae7a9..349cd794de3ae 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php
@@ -28,5 +28,5 @@ abstract class HourTransformer extends Transformer
      *
      * @return int The normalized hour value
      */
-    abstract public function normalizeHour($hour, $marker = null);
+    abstract public function normalizeHour(int $hour, string $marker = null): int;
 }
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php
index 08b5356e3fbd9..1f4dec8d1a161 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php
@@ -23,7 +23,7 @@ class MinuteTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $minuteOfHour = (int) $dateTime->format('i');
 
@@ -33,7 +33,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return 1 === $length ? '\d{1,2}' : '\d{'.$length.'}';
     }
@@ -41,7 +41,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'minute' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php
index 6d7c819800339..75ca2d897c100 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php
@@ -77,7 +77,7 @@ public function __construct()
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $matchLengthMap = array(
             1 => 'n',
@@ -100,7 +100,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         switch ($length) {
             case 1:
@@ -126,7 +126,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         if (!is_numeric($matched)) {
             if (3 === $length) {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php
index fa7e91d038f8c..ec02e7f3059ba 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php
@@ -23,7 +23,7 @@ class QuarterTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $month = (int) $dateTime->format('n');
         $quarter = (int) floor(($month - 1) / 3) + 1;
@@ -43,7 +43,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         switch ($length) {
             case 1:
@@ -59,7 +59,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array();
     }
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php
index dd2e7bd9f9bb5..6b1ffd0ce15d2 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php
@@ -23,7 +23,7 @@ class SecondTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $secondOfMinute = (int) $dateTime->format('s');
 
@@ -33,7 +33,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return 1 === $length ? '\d{1,2}' : '\d{'.$length.'}';
     }
@@ -41,7 +41,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'second' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimezoneTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimezoneTransformer.php
index 1cfcc9bdea021..03026a46a1ecb 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimezoneTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimezoneTransformer.php
@@ -27,7 +27,7 @@ class TimezoneTransformer extends Transformer
      *
      * @throws NotImplementedException When time zone is different than UTC or GMT (Etc/GMT)
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         $timeZone = substr($dateTime->getTimezone()->getName(), 0, 3);
 
@@ -63,7 +63,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return 'GMT[+-]\d{2}:?\d{2}';
     }
@@ -71,7 +71,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'timezone' => self::getEtcTimeZoneId($matched),
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php
index 26a25db355ca9..5bdb7267afd97 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php
@@ -29,7 +29,7 @@ abstract class Transformer
      *
      * @return string The formatted value
      */
-    abstract public function format(\DateTime $dateTime, $length);
+    abstract public function format(\DateTime $dateTime, int $length): string;
 
     /**
      * Returns a reverse matching regular expression of a string generated by format().
@@ -38,7 +38,7 @@ abstract public function format(\DateTime $dateTime, $length);
      *
      * @return string The reverse matching regular expression
      */
-    abstract public function getReverseMatchingRegExp($length);
+    abstract public function getReverseMatchingRegExp(int $length): string;
 
     /**
      * Extract date options from a matched value returned by the processing of the reverse matching
@@ -49,7 +49,7 @@ abstract public function getReverseMatchingRegExp($length);
      *
      * @return array An associative array
      */
-    abstract public function extractDateOptions($matched, $length);
+    abstract public function extractDateOptions(string $matched, int $length): array;
 
     /**
      * Pad a string with zeros to the left.
@@ -59,7 +59,7 @@ abstract public function extractDateOptions($matched, $length);
      *
      * @return string The padded string
      */
-    protected function padLeft($value, $length)
+    protected function padLeft(string $value, int $length): string
     {
         return str_pad($value, $length, '0', STR_PAD_LEFT);
     }
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php
index 0b546b774a40c..b41420b722179 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php
@@ -23,7 +23,7 @@ class YearTransformer extends Transformer
     /**
      * {@inheritdoc}
      */
-    public function format(\DateTime $dateTime, $length)
+    public function format(\DateTime $dateTime, int $length): string
     {
         if (2 === $length) {
             return $dateTime->format('y');
@@ -35,7 +35,7 @@ public function format(\DateTime $dateTime, $length)
     /**
      * {@inheritdoc}
      */
-    public function getReverseMatchingRegExp($length)
+    public function getReverseMatchingRegExp(int $length): string
     {
         return 2 === $length ? '\d{2}' : '\d{4}';
     }
@@ -43,7 +43,7 @@ public function getReverseMatchingRegExp($length)
     /**
      * {@inheritdoc}
      */
-    public function extractDateOptions($matched, $length)
+    public function extractDateOptions(string $matched, int $length): array
     {
         return array(
             'year' => (int) $matched,
diff --git a/src/Symfony/Component/Intl/Locale.php b/src/Symfony/Component/Intl/Locale.php
index ee09bd263cd42..3dfeacf3f314f 100644
--- a/src/Symfony/Component/Intl/Locale.php
+++ b/src/Symfony/Component/Intl/Locale.php
@@ -35,7 +35,7 @@ final class Locale extends \Locale
      *
      * @see getFallback()
      */
-    public static function setDefaultFallback($locale)
+    public static function setDefaultFallback(string $locale)
     {
         self::$defaultFallback = $locale;
     }
@@ -48,7 +48,7 @@ public static function setDefaultFallback($locale)
      * @see setDefaultFallback()
      * @see getFallback()
      */
-    public static function getDefaultFallback()
+    public static function getDefaultFallback(): string
     {
         return self::$defaultFallback;
     }
@@ -65,7 +65,7 @@ public static function getDefaultFallback()
      * @return string|null The ICU locale code of the fallback locale, or null
      *                     if no fallback exists
      */
-    public static function getFallback($locale)
+    public static function getFallback($locale): ?string
     {
         if (false === $pos = strrpos($locale, '_')) {
             if (self::$defaultFallback === $locale) {
@@ -78,7 +78,7 @@ public static function getFallback($locale)
                 return self::$defaultFallback;
             }
 
-            return;
+            return null;
         }
 
         return substr($locale, 0, $pos);
diff --git a/src/Symfony/Component/Intl/ResourceBundle/LanguageBundle.php b/src/Symfony/Component/Intl/ResourceBundle/LanguageBundle.php
index d12b892a10dcb..84c676c742b5c 100644
--- a/src/Symfony/Component/Intl/ResourceBundle/LanguageBundle.php
+++ b/src/Symfony/Component/Intl/ResourceBundle/LanguageBundle.php
@@ -36,15 +36,7 @@ class LanguageBundle extends LanguageDataProvider implements LanguageBundleInter
      */
     private $scriptProvider;
 
-    /**
-     * Creates a new language bundle.
-     *
-     * @param string                     $path
-     * @param BundleEntryReaderInterface $reader
-     * @param LocaleDataProvider         $localeProvider
-     * @param ScriptDataProvider         $scriptProvider
-     */
-    public function __construct($path, BundleEntryReaderInterface $reader, LocaleDataProvider $localeProvider, ScriptDataProvider $scriptProvider)
+    public function __construct(string $path, BundleEntryReaderInterface $reader, LocaleDataProvider $localeProvider, ScriptDataProvider $scriptProvider)
     {
         parent::__construct($path, $reader);
 
diff --git a/src/Symfony/Component/Ldap/Ldap.php b/src/Symfony/Component/Ldap/Ldap.php
index 514f51d22c21a..26fd4f946ccc9 100644
--- a/src/Symfony/Component/Ldap/Ldap.php
+++ b/src/Symfony/Component/Ldap/Ldap.php
@@ -70,7 +70,7 @@ public function escape($subject, $ignore = '', $flags = 0)
      *
      * @return static
      */
-    public static function create($adapter, array $config = array())
+    public static function create($adapter, array $config = array()): Ldap
     {
         if (!isset(self::$adapterMap[$adapter])) {
             throw new DriverNotFoundException(sprintf(
diff --git a/src/Symfony/Component/Lock/Key.php b/src/Symfony/Component/Lock/Key.php
index 5069901761820..95936a3e89f38 100644
--- a/src/Symfony/Component/Lock/Key.php
+++ b/src/Symfony/Component/Lock/Key.php
@@ -25,9 +25,9 @@ final class Key
     /**
      * @param string $resource
      */
-    public function __construct($resource)
+    public function __construct(string $resource)
     {
-        $this->resource = (string) $resource;
+        $this->resource = $resource;
     }
 
     public function __toString()
@@ -35,39 +35,22 @@ public function __toString()
         return $this->resource;
     }
 
-    /**
-     * @param string $stateKey
-     *
-     * @return bool
-     */
-    public function hasState($stateKey)
+    public function hasState(string $stateKey): bool
     {
         return isset($this->state[$stateKey]);
     }
 
-    /**
-     * @param string $stateKey
-     * @param mixed  $state
-     */
-    public function setState($stateKey, $state)
+    public function setState(string $stateKey, $state): void
     {
         $this->state[$stateKey] = $state;
     }
 
-    /**
-     * @param string $stateKey
-     */
-    public function removeState($stateKey)
+    public function removeState(string $stateKey): void
     {
         unset($this->state[$stateKey]);
     }
 
-    /**
-     * @param $stateKey
-     *
-     * @return mixed
-     */
-    public function getState($stateKey)
+    public function getState(string $stateKey)
     {
         return $this->state[$stateKey];
     }
diff --git a/src/Symfony/Component/PropertyAccess/PropertyAccess.php b/src/Symfony/Component/PropertyAccess/PropertyAccess.php
index 3c8dc1c56cc18..e929347e6536c 100644
--- a/src/Symfony/Component/PropertyAccess/PropertyAccess.php
+++ b/src/Symfony/Component/PropertyAccess/PropertyAccess.php
@@ -23,17 +23,12 @@ final class PropertyAccess
      *
      * @return PropertyAccessor
      */
-    public static function createPropertyAccessor()
+    public static function createPropertyAccessor(): PropertyAccessor
     {
         return self::createPropertyAccessorBuilder()->getPropertyAccessor();
     }
 
-    /**
-     * Creates a property accessor builder.
-     *
-     * @return PropertyAccessorBuilder
-     */
-    public static function createPropertyAccessorBuilder()
+    public static function createPropertyAccessorBuilder(): PropertyAccessorBuilder
     {
         return new PropertyAccessorBuilder();
     }
diff --git a/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php b/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
index 838fb9c4177f4..68506c4eb4da5 100644
--- a/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
+++ b/src/Symfony/Component/PropertyInfo/Extractor/ReflectionExtractor.php
@@ -162,18 +162,18 @@ public function isWritable($class, $property, array $context = array())
      *
      * @return Type[]|null
      */
-    private function extractFromMutator($class, $property)
+    private function extractFromMutator(string $class, string $property): ?array
     {
         list($reflectionMethod, $prefix) = $this->getMutatorMethod($class, $property);
         if (null === $reflectionMethod) {
-            return;
+            return null;
         }
 
         $reflectionParameters = $reflectionMethod->getParameters();
         $reflectionParameter = $reflectionParameters[0];
 
         if (!$reflectionType = $reflectionParameter->getType()) {
-            return;
+            return null;
         }
         $type = $this->extractFromReflectionType($reflectionType);
 
@@ -192,11 +192,11 @@ private function extractFromMutator($class, $property)
      *
      * @return Type[]|null
      */
-    private function extractFromAccessor($class, $property)
+    private function extractFromAccessor(string $class, string $property): ?array
     {
         list($reflectionMethod, $prefix) = $this->getAccessorMethod($class, $property);
         if (null === $reflectionMethod) {
-            return;
+            return null;
         }
 
         if ($reflectionType = $reflectionMethod->getReturnType()) {
@@ -206,6 +206,8 @@ private function extractFromAccessor($class, $property)
         if (in_array($prefix, array('is', 'can'))) {
             return array(new Type(Type::BUILTIN_TYPE_BOOL));
         }
+
+        return null;
     }
 
     /**
@@ -215,7 +217,7 @@ private function extractFromAccessor($class, $property)
      *
      * @return Type
      */
-    private function extractFromReflectionType(\ReflectionType $reflectionType)
+    private function extractFromReflectionType(\ReflectionType $reflectionType): Type
     {
         $phpTypeOrClass = $reflectionType->getName();
         $nullable = $reflectionType->allowsNull();
@@ -241,7 +243,7 @@ private function extractFromReflectionType(\ReflectionType $reflectionType)
      *
      * @return bool
      */
-    private function isPublicProperty($class, $property)
+    private function isPublicProperty(string $class, string $property): bool
     {
         try {
             $reflectionProperty = new \ReflectionProperty($class, $property);
@@ -265,7 +267,7 @@ private function isPublicProperty($class, $property)
      *
      * @return array|null
      */
-    private function getAccessorMethod($class, $property)
+    private function getAccessorMethod(string $class, string $property): ?array
     {
         $ucProperty = ucfirst($property);
 
@@ -283,6 +285,8 @@ private function getAccessorMethod($class, $property)
                 // Return null if the property doesn't exist
             }
         }
+
+        return null;
     }
 
     /**
@@ -296,7 +300,7 @@ private function getAccessorMethod($class, $property)
      *
      * @return array
      */
-    private function getMutatorMethod($class, $property)
+    private function getMutatorMethod(string $class, string $property)
     {
         $ucProperty = ucfirst($property);
         $ucSingulars = (array) Inflector::singularize($ucProperty);
@@ -333,7 +337,7 @@ private function getMutatorMethod($class, $property)
      *
      * @return string
      */
-    private function getPropertyName($methodName, array $reflectionProperties)
+    private function getPropertyName(string $methodName, array $reflectionProperties)
     {
         $pattern = implode('|', array_merge($this->accessorPrefixes, $this->mutatorPrefixes));
 
diff --git a/src/Symfony/Component/PropertyInfo/Util/PhpDocTypeHelper.php b/src/Symfony/Component/PropertyInfo/Util/PhpDocTypeHelper.php
index bc14cd8b69b1b..9c8fc8d3f676f 100644
--- a/src/Symfony/Component/PropertyInfo/Util/PhpDocTypeHelper.php
+++ b/src/Symfony/Component/PropertyInfo/Util/PhpDocTypeHelper.php
@@ -27,9 +27,9 @@ final class PhpDocTypeHelper
     /**
      * Creates a {@see Type} from a PHPDoc type.
      *
-     * @return Type
+     * @return Type[]
      */
-    public function getTypes(DocType $varType)
+    public function getTypes(DocType $varType): array
     {
         $types = array();
         $nullable = false;
@@ -79,11 +79,11 @@ public function getTypes(DocType $varType)
      *
      * @return Type|null
      */
-    private function createType($docType, $nullable)
+    private function createType(string $docType, bool $nullable): ?Type
     {
         // Cannot guess
         if (!$docType || 'mixed' === $docType) {
-            return;
+            return null;
         }
 
         if ($collection = '[]' === substr($docType, -2)) {
@@ -110,14 +110,7 @@ private function createType($docType, $nullable)
         return new Type($phpType, $nullable, $class);
     }
 
-    /**
-     * Normalizes the type.
-     *
-     * @param string $docType
-     *
-     * @return string
-     */
-    private function normalizeType($docType)
+    private function normalizeType(string $docType): string
     {
         switch ($docType) {
             case 'integer':
@@ -141,14 +134,7 @@ private function normalizeType($docType)
         }
     }
 
-    /**
-     * Gets an array containing the PHP type and the class.
-     *
-     * @param string $docType
-     *
-     * @return array
-     */
-    private function getPhpTypeAndClass($docType)
+    private function getPhpTypeAndClass(string $docType): array
     {
         if (in_array($docType, Type::$builtinTypes)) {
             return array($docType, null);
diff --git a/src/Symfony/Component/Routing/Matcher/Dumper/DumperRoute.php b/src/Symfony/Component/Routing/Matcher/Dumper/DumperRoute.php
index 3ad08c2006f24..9895de9110879 100644
--- a/src/Symfony/Component/Routing/Matcher/Dumper/DumperRoute.php
+++ b/src/Symfony/Component/Routing/Matcher/Dumper/DumperRoute.php
@@ -32,34 +32,18 @@ class DumperRoute
      */
     private $route;
 
-    /**
-     * Constructor.
-     *
-     * @param string $name  The route name
-     * @param Route  $route The route
-     */
-    public function __construct($name, Route $route)
+    public function __construct(string $name, Route $route)
     {
         $this->name = $name;
         $this->route = $route;
     }
 
-    /**
-     * Returns the route name.
-     *
-     * @return string The route name
-     */
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
 
-    /**
-     * Returns the route.
-     *
-     * @return Route The route
-     */
-    public function getRoute()
+    public function getRoute(): Route
     {
         return $this->route;
     }
diff --git a/src/Symfony/Component/Routing/Matcher/Dumper/StaticPrefixCollection.php b/src/Symfony/Component/Routing/Matcher/Dumper/StaticPrefixCollection.php
index b2bfa343764cc..675dab9193262 100644
--- a/src/Symfony/Component/Routing/Matcher/Dumper/StaticPrefixCollection.php
+++ b/src/Symfony/Component/Routing/Matcher/Dumper/StaticPrefixCollection.php
@@ -35,12 +35,12 @@ class StaticPrefixCollection
      */
     private $matchStart = 0;
 
-    public function __construct($prefix = '')
+    public function __construct(string $prefix = '')
     {
         $this->prefix = $prefix;
     }
 
-    public function getPrefix()
+    public function getPrefix(): string
     {
         return $this->prefix;
     }
@@ -48,7 +48,7 @@ public function getPrefix()
     /**
      * @return mixed[]|StaticPrefixCollection[]
      */
-    public function getItems()
+    public function getItems(): array
     {
         return $this->items;
     }
@@ -59,7 +59,7 @@ public function getItems()
      * @param string $prefix
      * @param mixed  $route
      */
-    public function addRoute($prefix, $route)
+    public function addRoute(string $prefix, $route)
     {
         $prefix = '/' === $prefix ? $prefix : rtrim($prefix, '/');
         $this->guardAgainstAddingNotAcceptedRoutes($prefix);
@@ -108,7 +108,7 @@ public function addRoute($prefix, $route)
      *
      * @return null|StaticPrefixCollection
      */
-    private function groupWithItem($item, $prefix, $route)
+    private function groupWithItem($item, string $prefix, $route)
     {
         $itemPrefix = $item instanceof self ? $item->prefix : $item[0];
         $commonPrefix = $this->detectCommonPrefix($prefix, $itemPrefix);
@@ -137,7 +137,7 @@ private function groupWithItem($item, $prefix, $route)
      *
      * @return bool Whether a prefix could belong in a given group
      */
-    private function accepts($prefix)
+    private function accepts(string $prefix): bool
     {
         return '' === $this->prefix || strpos($prefix, $this->prefix) === 0;
     }
@@ -150,7 +150,7 @@ private function accepts($prefix)
      *
      * @return false|string A common prefix, longer than the base/group prefix, or false when none available
      */
-    private function detectCommonPrefix($prefix, $anotherPrefix)
+    private function detectCommonPrefix(string $prefix, string $anotherPrefix)
     {
         $baseLength = strlen($this->prefix);
         $commonLength = $baseLength;
@@ -176,7 +176,7 @@ private function detectCommonPrefix($prefix, $anotherPrefix)
     /**
      * Optimizes the tree by inlining items from groups with less than 3 items.
      */
-    public function optimizeGroups()
+    public function optimizeGroups(): void
     {
         $index = -1;
 
@@ -199,7 +199,7 @@ public function optimizeGroups()
         }
     }
 
-    private function shouldBeInlined()
+    private function shouldBeInlined(): bool
     {
         if (count($this->items) >= 3) {
             return false;
@@ -227,7 +227,7 @@ private function shouldBeInlined()
      *
      * @throws \LogicException When a prefix does not belong in a group.
      */
-    private function guardAgainstAddingNotAcceptedRoutes($prefix)
+    private function guardAgainstAddingNotAcceptedRoutes(string $prefix)
     {
         if (!$this->accepts($prefix)) {
             $message = sprintf('Could not add route with prefix %s to collection with prefix %s', $prefix, $this->prefix);
diff --git a/src/Symfony/Component/Routing/RouteCollectionBuilder.php b/src/Symfony/Component/Routing/RouteCollectionBuilder.php
index 3998ce1ededd4..6044ca99d3d1f 100644
--- a/src/Symfony/Component/Routing/RouteCollectionBuilder.php
+++ b/src/Symfony/Component/Routing/RouteCollectionBuilder.php
@@ -258,7 +258,7 @@ public function setMethods($methods)
      *
      * @return $this
      */
-    private function addResource(ResourceInterface $resource)
+    private function addResource(ResourceInterface $resource): RouteCollectionBuilder
     {
         $this->resources[] = $resource;
 
@@ -356,7 +356,7 @@ private function generateRouteName(Route $route)
      *
      * @throws FileLoaderLoadException If no loader is found
      */
-    private function load($resource, $type = null)
+    private function load($resource, string $type = null): array
     {
         if (null === $this->loader) {
             throw new \BadMethodCallException('Cannot import other routing resources: you must pass a LoaderInterface when constructing RouteCollectionBuilder.');
diff --git a/src/Symfony/Component/Security/Core/Authentication/RememberMe/PersistentToken.php b/src/Symfony/Component/Security/Core/Authentication/RememberMe/PersistentToken.php
index 76873fc603cd7..996ad285fdab0 100644
--- a/src/Symfony/Component/Security/Core/Authentication/RememberMe/PersistentToken.php
+++ b/src/Symfony/Component/Security/Core/Authentication/RememberMe/PersistentToken.php
@@ -24,18 +24,7 @@ final class PersistentToken implements PersistentTokenInterface
     private $tokenValue;
     private $lastUsed;
 
-    /**
-     * Constructor.
-     *
-     * @param string    $class
-     * @param string    $username
-     * @param string    $series
-     * @param string    $tokenValue
-     * @param \DateTime $lastUsed
-     *
-     * @throws \InvalidArgumentException
-     */
-    public function __construct($class, $username, $series, $tokenValue, \DateTime $lastUsed)
+    public function __construct(string $class, string $username, string $series, string $tokenValue, \DateTime $lastUsed)
     {
         if (empty($class)) {
             throw new \InvalidArgumentException('$class must not be empty.');
diff --git a/src/Symfony/Component/Security/Http/Firewall/ExceptionListener.php b/src/Symfony/Component/Security/Http/Firewall/ExceptionListener.php
index fc279c0b3ab96..2091c84f60ebe 100644
--- a/src/Symfony/Component/Security/Http/Firewall/ExceptionListener.php
+++ b/src/Symfony/Component/Security/Http/Firewall/ExceptionListener.php
@@ -104,7 +104,7 @@ public function onKernelException(GetResponseForExceptionEvent $event)
         } while (null !== $exception = $exception->getPrevious());
     }
 
-    private function handleAuthenticationException(GetResponseForExceptionEvent $event, AuthenticationException $exception)
+    private function handleAuthenticationException(GetResponseForExceptionEvent $event, AuthenticationException $exception): void
     {
         if (null !== $this->logger) {
             $this->logger->info('An AuthenticationException was thrown; redirecting to authentication entry point.', array('exception' => $exception));
@@ -167,22 +167,14 @@ private function handleAccessDeniedException(GetResponseForExceptionEvent $event
         }
     }
 
-    private function handleLogoutException(LogoutException $exception)
+    private function handleLogoutException(LogoutException $exception): void
     {
         if (null !== $this->logger) {
             $this->logger->info('A LogoutException was thrown.', array('exception' => $exception));
         }
     }
 
-    /**
-     * @param Request                 $request
-     * @param AuthenticationException $authException
-     *
-     * @return Response
-     *
-     * @throws AuthenticationException
-     */
-    private function startAuthentication(Request $request, AuthenticationException $authException)
+    private function startAuthentication(Request $request, AuthenticationException $authException): Response
     {
         if (null === $this->authenticationEntryPoint) {
             throw $authException;
@@ -216,9 +208,6 @@ private function startAuthentication(Request $request, AuthenticationException $
         return $response;
     }
 
-    /**
-     * @param Request $request
-     */
     protected function setTargetPath(Request $request)
     {
         // session isn't required when using HTTP basic authentication mechanism for example
diff --git a/src/Symfony/Component/Translation/Translator.php b/src/Symfony/Component/Translation/Translator.php
index 897aced2717b5..c877e43ba2e65 100644
--- a/src/Symfony/Component/Translation/Translator.php
+++ b/src/Symfony/Component/Translation/Translator.php
@@ -280,10 +280,7 @@ protected function initializeCatalogue($locale)
         $this->loadFallbackCatalogues($locale);
     }
 
-    /**
-     * @param string $locale
-     */
-    private function initializeCacheCatalogue($locale)
+    private function initializeCacheCatalogue(string $locale): void
     {
         if (isset($this->catalogues[$locale])) {
             /* Catalogue already initialized. */
@@ -306,7 +303,7 @@ function (ConfigCacheInterface $cache) use ($locale) {
         $this->catalogues[$locale] = include $cache->getPath();
     }
 
-    private function dumpCatalogue($locale, ConfigCacheInterface $cache)
+    private function dumpCatalogue($locale, ConfigCacheInterface $cache): void
     {
         $this->initializeCatalogue($locale);
         $fallbackContent = $this->getFallbackContent($this->catalogues[$locale]);
@@ -331,7 +328,7 @@ private function dumpCatalogue($locale, ConfigCacheInterface $cache)
         $cache->write($content, $this->catalogues[$locale]->getResources());
     }
 
-    private function getFallbackContent(MessageCatalogue $catalogue)
+    private function getFallbackContent(MessageCatalogue $catalogue): string
     {
         $fallbackContent = '';
         $current = '';
@@ -366,7 +363,7 @@ private function getCatalogueCachePath($locale)
         return $this->cacheDir.'/catalogue.'.$locale.'.'.strtr(substr(base64_encode(hash('sha256', serialize($this->fallbackLocales), true)), 0, 7), '/', '_').'.php';
     }
 
-    private function doLoadCatalogue($locale)
+    private function doLoadCatalogue($locale): void
     {
         $this->catalogues[$locale] = new MessageCatalogue($locale);
 
@@ -380,7 +377,7 @@ private function doLoadCatalogue($locale)
         }
     }
 
-    private function loadFallbackCatalogues($locale)
+    private function loadFallbackCatalogues($locale): void
     {
         $current = $this->catalogues[$locale];
 
@@ -436,7 +433,7 @@ protected function assertValidLocale($locale)
      *
      * @return ConfigCacheFactoryInterface $configCacheFactory
      */
-    private function getConfigCacheFactory()
+    private function getConfigCacheFactory(): ConfigCacheFactoryInterface
     {
         if (!$this->configCacheFactory) {
             $this->configCacheFactory = new ConfigCacheFactory($this->debug);
diff --git a/src/Symfony/Component/Validator/Validation.php b/src/Symfony/Component/Validator/Validation.php
index 950efb6cce267..71edfedb1839a 100644
--- a/src/Symfony/Component/Validator/Validation.php
+++ b/src/Symfony/Component/Validator/Validation.php
@@ -28,7 +28,7 @@ final class Validation
      *
      * @return ValidatorInterface The new validator
      */
-    public static function createValidator()
+    public static function createValidator(): ValidatorInterface
     {
         return self::createValidatorBuilder()->getValidator();
     }
@@ -38,7 +38,7 @@ public static function createValidator()
      *
      * @return ValidatorBuilderInterface The new builder
      */
-    public static function createValidatorBuilder()
+    public static function createValidatorBuilder(): ValidatorBuilder
     {
         return new ValidatorBuilder();
     }
diff --git a/src/Symfony/Component/WebLink/HttpHeaderSerializer.php b/src/Symfony/Component/WebLink/HttpHeaderSerializer.php
index 66bfa55ab4a8b..01bb9f154b82d 100644
--- a/src/Symfony/Component/WebLink/HttpHeaderSerializer.php
+++ b/src/Symfony/Component/WebLink/HttpHeaderSerializer.php
@@ -29,7 +29,7 @@ final class HttpHeaderSerializer
      *
      * @return string|null
      */
-    public function serialize($links)
+    public function serialize(iterable $links)
     {
         $elements = array();
         foreach ($links as $link) {
diff --git a/src/Symfony/Component/Workflow/Definition.php b/src/Symfony/Component/Workflow/Definition.php
index 5f8571b329a09..a8bc0806e2906 100644
--- a/src/Symfony/Component/Workflow/Definition.php
+++ b/src/Symfony/Component/Workflow/Definition.php
@@ -30,7 +30,7 @@ final class Definition
      * @param Transition[] $transitions
      * @param string|null  $initialPlace
      */
-    public function __construct(array $places, array $transitions, $initialPlace = null)
+    public function __construct(array $places, array $transitions, string $initialPlace = null)
     {
         foreach ($places as $place) {
             $this->addPlace($place);
@@ -54,7 +54,7 @@ public function getInitialPlace()
     /**
      * @return string[]
      */
-    public function getPlaces()
+    public function getPlaces(): array
     {
         return $this->places;
     }
@@ -62,12 +62,12 @@ public function getPlaces()
     /**
      * @return Transition[]
      */
-    public function getTransitions()
+    public function getTransitions(): array
     {
         return $this->transitions;
     }
 
-    private function setInitialPlace($place)
+    private function setInitialPlace(string $place = null)
     {
         if (null === $place) {
             return;
@@ -80,7 +80,7 @@ private function setInitialPlace($place)
         $this->initialPlace = $place;
     }
 
-    private function addPlace($place)
+    private function addPlace(string $place)
     {
         if (!preg_match('{^[\w\d_-]+$}', $place)) {
             throw new InvalidArgumentException(sprintf('The place "%s" contains invalid characters.', $place));
diff --git a/src/Symfony/Component/Workflow/Dumper/GraphvizDumper.php b/src/Symfony/Component/Workflow/Dumper/GraphvizDumper.php
index 3681b6f1391a8..1344980bee711 100644
--- a/src/Symfony/Component/Workflow/Dumper/GraphvizDumper.php
+++ b/src/Symfony/Component/Workflow/Dumper/GraphvizDumper.php
@@ -201,7 +201,7 @@ protected function dotize($id)
         return strtolower(preg_replace('/[^\w]/i', '_', $id));
     }
 
-    private function addAttributes(array $attributes)
+    private function addAttributes(array $attributes): string
     {
         $code = array();
 
@@ -212,7 +212,7 @@ private function addAttributes(array $attributes)
         return $code ? ', '.implode(', ', $code) : '';
     }
 
-    private function addOptions(array $options)
+    private function addOptions(array $options): string
     {
         $code = array();
 
diff --git a/src/Symfony/Component/Workflow/EventListener/GuardListener.php b/src/Symfony/Component/Workflow/EventListener/GuardListener.php
index 20ba04c007fc2..ad281f0fb8f4c 100644
--- a/src/Symfony/Component/Workflow/EventListener/GuardListener.php
+++ b/src/Symfony/Component/Workflow/EventListener/GuardListener.php
@@ -51,7 +51,7 @@ public function onTransition(GuardEvent $event, $eventName)
     }
 
     // code should be sync with Symfony\Component\Security\Core\Authorization\Voter\ExpressionVoter
-    private function getVariables(GuardEvent $event)
+    private function getVariables(GuardEvent $event): array
     {
         $token = $this->tokenStorage->getToken();
 
diff --git a/src/Symfony/Component/Workflow/Registry.php b/src/Symfony/Component/Workflow/Registry.php
index b10af2fbbc0a4..2430dcb34ceaf 100644
--- a/src/Symfony/Component/Workflow/Registry.php
+++ b/src/Symfony/Component/Workflow/Registry.php
@@ -61,7 +61,7 @@ public function get($subject, $workflowName = null)
         return $matched;
     }
 
-    private function supports(Workflow $workflow, SupportStrategyInterface $supportStrategy, $subject, $workflowName)
+    private function supports(Workflow $workflow, SupportStrategyInterface $supportStrategy, $subject, $workflowName): bool
     {
         if (null !== $workflowName && $workflowName !== $workflow->getName()) {
             return false;
diff --git a/src/Symfony/Component/Workflow/SupportStrategy/ClassInstanceSupportStrategy.php b/src/Symfony/Component/Workflow/SupportStrategy/ClassInstanceSupportStrategy.php
index 8828946dbf543..ed4cd4e6ab189 100644
--- a/src/Symfony/Component/Workflow/SupportStrategy/ClassInstanceSupportStrategy.php
+++ b/src/Symfony/Component/Workflow/SupportStrategy/ClassInstanceSupportStrategy.php
@@ -11,10 +11,7 @@ final class ClassInstanceSupportStrategy implements SupportStrategyInterface
 {
     private $className;
 
-    /**
-     * @param string $className a FQCN
-     */
-    public function __construct($className)
+    public function __construct(string $className)
     {
         $this->className = $className;
     }
diff --git a/src/Symfony/Component/Yaml/Dumper.php b/src/Symfony/Component/Yaml/Dumper.php
index 87e06b5255453..92ce4c9d28f3f 100644
--- a/src/Symfony/Component/Yaml/Dumper.php
+++ b/src/Symfony/Component/Yaml/Dumper.php
@@ -27,10 +27,7 @@ class Dumper
      */
     protected $indentation;
 
-    /**
-     * @param int $indentation
-     */
-    public function __construct($indentation = 4)
+    public function __construct(int $indentation = 4)
     {
         if ($indentation < 1) {
             throw new \InvalidArgumentException('The indentation must be greater than zero.');
@@ -49,7 +46,7 @@ public function __construct($indentation = 4)
      *
      * @return string The YAML representation of the PHP value
      */
-    public function dump($input, $inline = 0, $indent = 0, $flags = 0)
+    public function dump($input, int $inline = 0, int $indent = 0, int $flags = 0): string
     {
         $output = '';
         $prefix = $indent ? str_repeat(' ', $indent) : '';
diff --git a/src/Symfony/Component/Yaml/Escaper.php b/src/Symfony/Component/Yaml/Escaper.php
index 94bb3924b618b..66e65bc618c24 100644
--- a/src/Symfony/Component/Yaml/Escaper.php
+++ b/src/Symfony/Component/Yaml/Escaper.php
@@ -50,7 +50,7 @@ class Escaper
      *
      * @return bool True if the value would require double quotes
      */
-    public static function requiresDoubleQuoting($value)
+    public static function requiresDoubleQuoting(string $value): bool
     {
         return 0 < preg_match('/'.self::REGEX_CHARACTER_TO_ESCAPE.'/u', $value);
     }
@@ -62,7 +62,7 @@ public static function requiresDoubleQuoting($value)
      *
      * @return string The quoted, escaped string
      */
-    public static function escapeWithDoubleQuotes($value)
+    public static function escapeWithDoubleQuotes(string $value): string
     {
         return sprintf('"%s"', str_replace(self::$escapees, self::$escaped, $value));
     }
@@ -74,7 +74,7 @@ public static function escapeWithDoubleQuotes($value)
      *
      * @return bool True if the value would require single quotes
      */
-    public static function requiresSingleQuoting($value)
+    public static function requiresSingleQuoting(string $value): bool
     {
         // Determines if a PHP value is entirely composed of a value that would
         // require single quoting in YAML.
@@ -94,7 +94,7 @@ public static function requiresSingleQuoting($value)
      *
      * @return string The quoted, escaped string
      */
-    public static function escapeWithSingleQuotes($value)
+    public static function escapeWithSingleQuotes(string $value): string
     {
         return sprintf("'%s'", str_replace('\'', '\'\'', $value));
     }
diff --git a/src/Symfony/Component/Yaml/Exception/ParseException.php b/src/Symfony/Component/Yaml/Exception/ParseException.php
index 3b38b643964ac..b04cbd69cece6 100644
--- a/src/Symfony/Component/Yaml/Exception/ParseException.php
+++ b/src/Symfony/Component/Yaml/Exception/ParseException.php
@@ -32,7 +32,7 @@ class ParseException extends RuntimeException
      * @param string|null     $parsedFile The file name where the error occurred
      * @param \Exception|null $previous   The previous exception
      */
-    public function __construct($message, $parsedLine = -1, $snippet = null, $parsedFile = null, \Exception $previous = null)
+    public function __construct(string $message, int $parsedLine = -1, string $snippet = null, string $parsedFile = null, \Exception $previous = null)
     {
         $this->parsedFile = $parsedFile;
         $this->parsedLine = $parsedLine;
diff --git a/src/Symfony/Component/Yaml/Inline.php b/src/Symfony/Component/Yaml/Inline.php
index 3212aeca58963..cc7f723726eed 100644
--- a/src/Symfony/Component/Yaml/Inline.php
+++ b/src/Symfony/Component/Yaml/Inline.php
@@ -44,7 +44,7 @@ class Inline
      *
      * @throws ParseException
      */
-    public static function parse($value, $flags = 0, $references = array())
+    public static function parse(string $value = null, int $flags = 0, array $references = array())
     {
         self::$exceptionOnInvalidType = (bool) (Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE & $flags);
         self::$objectSupport = (bool) (Yaml::PARSE_OBJECT & $flags);
@@ -103,7 +103,7 @@ public static function parse($value, $flags = 0, $references = array())
      *
      * @throws DumpException When trying to dump PHP resource
      */
-    public static function dump($value, $flags = 0)
+    public static function dump($value, int $flags = 0): string
     {
         switch (true) {
             case is_resource($value):
@@ -124,7 +124,13 @@ public static function dump($value, $flags = 0)
                 }
 
                 if (Yaml::DUMP_OBJECT_AS_MAP & $flags && ($value instanceof \stdClass || $value instanceof \ArrayObject)) {
-                    return self::dumpArray($value, $flags & ~Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE);
+                    $output = array();
+
+                    foreach ($value as $key => $val) {
+                        $output[] = sprintf('%s: %s', self::dump($key, $flags), self::dump($val, $flags));
+                    }
+
+                    return sprintf('{ %s }', implode(', ', $output));
                 }
 
                 if (Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE & $flags) {
@@ -182,13 +188,11 @@ public static function dump($value, $flags = 0)
     /**
      * Check if given array is hash or just normal indexed array.
      *
-     * @internal
-     *
      * @param array|\ArrayObject|\stdClass $value The PHP array or array-like object to check
      *
      * @return bool true if value is hash array, false otherwise
      */
-    public static function isHash($value)
+    public static function isHash($value): bool
     {
         if ($value instanceof \stdClass || $value instanceof \ArrayObject) {
             return true;
@@ -213,7 +217,7 @@ public static function isHash($value)
      *
      * @return string The YAML string representing the PHP array
      */
-    private static function dumpArray($value, $flags)
+    private static function dumpArray(array $value, int $flags): string
     {
         // array
         if (($value || Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE & $flags) && !self::isHash($value)) {
@@ -244,13 +248,11 @@ private static function dumpArray($value, $flags)
      * @param bool     $evaluate
      * @param array    $references
      *
-     * @return string
+     * @return mixed
      *
      * @throws ParseException When malformed inline YAML string is parsed
-     *
-     * @internal
      */
-    public static function parseScalar($scalar, $flags = 0, $delimiters = null, &$i = 0, $evaluate = true, $references = array())
+    public static function parseScalar(string $scalar, int $flags = 0, array $delimiters = null, int &$i = 0, bool $evaluate = true, array $references = array())
     {
         if (in_array($scalar[$i], array('"', "'"))) {
             // quoted scalar
@@ -302,7 +304,7 @@ public static function parseScalar($scalar, $flags = 0, $delimiters = null, &$i
      *
      * @throws ParseException When malformed inline YAML string is parsed
      */
-    private static function parseQuotedScalar($scalar, &$i)
+    private static function parseQuotedScalar(string $scalar, int &$i): string
     {
         if (!Parser::preg_match('/'.self::REGEX_QUOTED_STRING.'/Au', substr($scalar, $i), $match)) {
             throw new ParseException(sprintf('Malformed inline YAML string: %s.', substr($scalar, $i)));
@@ -334,7 +336,7 @@ private static function parseQuotedScalar($scalar, &$i)
      *
      * @throws ParseException When malformed inline YAML string is parsed
      */
-    private static function parseSequence($sequence, $flags, &$i = 0, $references = array())
+    private static function parseSequence(string $sequence, int $flags, int &$i = 0, array $references = array()): array
     {
         $output = array();
         $len = strlen($sequence);
@@ -403,7 +405,7 @@ private static function parseSequence($sequence, $flags, &$i = 0, $references =
      *
      * @throws ParseException When malformed inline YAML string is parsed
      */
-    private static function parseMapping($mapping, $flags, &$i = 0, $references = array())
+    private static function parseMapping(string $mapping, int $flags, int &$i = 0, array $references = array())
     {
         $output = array();
         $len = strlen($mapping);
@@ -515,7 +517,7 @@ private static function parseMapping($mapping, $flags, &$i = 0, $references = ar
      *
      * @throws ParseException when object parsing support was disabled and the parser detected a PHP object or when a reference could not be resolved
      */
-    private static function evaluateScalar($scalar, $flags, $references = array())
+    private static function evaluateScalar(string $scalar, int $flags, array $references = array())
     {
         $scalar = trim($scalar);
         $scalarLower = strtolower($scalar);
@@ -638,10 +640,10 @@ private static function evaluateScalar($scalar, $flags, $references = array())
      *
      * @return null|string
      */
-    private static function parseTag($value, &$i, $flags)
+    private static function parseTag(string $value, int &$i, int $flags): ?string
     {
         if ('!' !== $value[$i]) {
-            return;
+            return null;
         }
 
         $tagLength = strcspn($value, " \t\n[]{},", $i + 1);
@@ -653,7 +655,7 @@ private static function parseTag($value, &$i, $flags)
         // Is followed by a scalar and is a built-in tag
         if ($tag && (!isset($value[$nextOffset]) || !in_array($value[$nextOffset], array('[', '{'), true)) && ('!' === $tag[0] || 'str' === $tag || 'php/const' === $tag || 'php/object' === $tag)) {
             // Manage in {@link self::evaluateScalar()}
-            return;
+            return null;
         }
 
         $i = $nextOffset;
@@ -674,10 +676,8 @@ private static function parseTag($value, &$i, $flags)
      * @param string $scalar
      *
      * @return string
-     *
-     * @internal
      */
-    public static function evaluateBinaryScalar($scalar)
+    public static function evaluateBinaryScalar(string $scalar): string
     {
         $parsedBinaryData = self::parseScalar(preg_replace('/\s/', '', $scalar));
 
@@ -692,7 +692,7 @@ public static function evaluateBinaryScalar($scalar)
         return base64_decode($parsedBinaryData, true);
     }
 
-    private static function isBinaryString($value)
+    private static function isBinaryString(string $value)
     {
         return !preg_match('//u', $value) || preg_match('/[^\x00\x07-\x0d\x1B\x20-\xff]/', $value);
     }
@@ -704,7 +704,7 @@ private static function isBinaryString($value)
      *
      * @see http://www.yaml.org/spec/1.2/spec.html#id2761573
      */
-    private static function getTimestampRegex()
+    private static function getTimestampRegex(): string
     {
         return <<<EOF
         ~^
@@ -727,7 +727,7 @@ private static function getTimestampRegex()
      *
      * @return string
      */
-    private static function getHexRegex()
+    private static function getHexRegex(): string
     {
         return '~^0x[0-9a-f_]++$~i';
     }
diff --git a/src/Symfony/Component/Yaml/Parser.php b/src/Symfony/Component/Yaml/Parser.php
index 41898fe54afc5..96390f4a2095a 100644
--- a/src/Symfony/Component/Yaml/Parser.php
+++ b/src/Symfony/Component/Yaml/Parser.php
@@ -45,7 +45,7 @@ class Parser
      *
      * @throws ParseException If the YAML is not valid
      */
-    public function parse($value, $flags = 0)
+    public function parse(string $value, int $flags = 0)
     {
         if (false === preg_match('//u', $value)) {
             throw new ParseException('The YAML value does not appear to be valid UTF-8.');
@@ -82,12 +82,12 @@ public function parse($value, $flags = 0)
      *
      * @return int
      */
-    public function getLastLineNumberBeforeDeprecation()
+    public function getLastLineNumberBeforeDeprecation(): int
     {
         return $this->getRealCurrentLineNb();
     }
 
-    private function doParse($value, $flags)
+    private function doParse(string $value, int $flags)
     {
         $this->currentLineNb = -1;
         $this->currentLine = '';
@@ -146,7 +146,7 @@ private function doParse($value, $flags)
 
                 // array
                 if (!isset($values['value']) || '' == trim($values['value'], ' ') || 0 === strpos(ltrim($values['value'], ' '), '#')) {
-                    $data[] = $this->parseBlock($this->getRealCurrentLineNb() + 1, $this->getNextEmbedBlock(null, true), $flags);
+                    $data[] = $this->parseBlock($this->getRealCurrentLineNb() + 1, $this->getNextEmbedBlock(null, true) ?? '', $flags);
                 } elseif (null !== $subTag = $this->getLineTag(ltrim($values['value'], ' '), $flags)) {
                     $data[] = new TaggedValue(
                         $subTag,
@@ -383,7 +383,7 @@ private function doParse($value, $flags)
         return empty($data) ? null : $data;
     }
 
-    private function parseBlock($offset, $yaml, $flags)
+    private function parseBlock(int $offset, string $yaml, int $flags)
     {
         $skippedLineNumbers = $this->skippedLineNumbers;
 
@@ -411,7 +411,7 @@ private function parseBlock($offset, $yaml, $flags)
      *
      * @return int The current line number
      */
-    public function getRealCurrentLineNb()
+    public function getRealCurrentLineNb(): int
     {
         $realCurrentLineNumber = $this->currentLineNb + $this->offset;
 
@@ -431,7 +431,7 @@ public function getRealCurrentLineNb()
      *
      * @return int The current line indentation
      */
-    private function getCurrentLineIndentation()
+    private function getCurrentLineIndentation(): int
     {
         return strlen($this->currentLine) - strlen(ltrim($this->currentLine, ' '));
     }
@@ -439,14 +439,14 @@ private function getCurrentLineIndentation()
     /**
      * Returns the next embed block of YAML.
      *
-     * @param int  $indentation The indent level at which the block is to be read, or null for default
-     * @param bool $inSequence  True if the enclosing data structure is a sequence
+     * @param int|null $indentation The indent level at which the block is to be read, or null for default
+     * @param bool     $inSequence  True if the enclosing data structure is a sequence
      *
      * @return string A YAML string
      *
      * @throws ParseException When indentation problem are detected
      */
-    private function getNextEmbedBlock($indentation = null, $inSequence = false)
+    private function getNextEmbedBlock(int $indentation = null, bool $inSequence = false): ?string
     {
         $oldLineIndentation = $this->getCurrentLineIndentation();
         $blockScalarIndentations = array();
@@ -456,7 +456,7 @@ private function getNextEmbedBlock($indentation = null, $inSequence = false)
         }
 
         if (!$this->moveToNextLine()) {
-            return;
+            return null;
         }
 
         if (null === $indentation) {
@@ -477,7 +477,7 @@ private function getNextEmbedBlock($indentation = null, $inSequence = false)
         } else {
             $this->moveToPreviousLine();
 
-            return;
+            return null;
         }
 
         if ($inSequence && $oldLineIndentation === $newIndent && isset($data[0][0]) && '-' === $data[0][0]) {
@@ -485,7 +485,7 @@ private function getNextEmbedBlock($indentation = null, $inSequence = false)
             // and therefore no nested list or mapping
             $this->moveToPreviousLine();
 
-            return;
+            return null;
         }
 
         $isItUnindentedCollection = $this->isStringUnIndentedCollectionItem();
@@ -556,7 +556,7 @@ private function getNextEmbedBlock($indentation = null, $inSequence = false)
      *
      * @return bool
      */
-    private function moveToNextLine()
+    private function moveToNextLine(): bool
     {
         if ($this->currentLineNb >= count($this->lines) - 1) {
             return false;
@@ -572,7 +572,7 @@ private function moveToNextLine()
      *
      * @return bool
      */
-    private function moveToPreviousLine()
+    private function moveToPreviousLine(): bool
     {
         if ($this->currentLineNb < 1) {
             return false;
@@ -594,7 +594,7 @@ private function moveToPreviousLine()
      *
      * @throws ParseException When reference does not exist
      */
-    private function parseValue($value, $flags, $context)
+    private function parseValue(string $value, int $flags, string $context)
     {
         if (0 === strpos($value, '*')) {
             if (false !== $pos = strpos($value, '#')) {
@@ -675,7 +675,7 @@ private function parseValue($value, $flags, $context)
      *
      * @return string The text value
      */
-    private function parseBlockScalar($style, $chomping = '', $indentation = 0)
+    private function parseBlockScalar(string $style, string $chomping = '', int $indentation = 0): string
     {
         $notEOF = $this->moveToNextLine();
         if (!$notEOF) {
@@ -782,7 +782,7 @@ private function parseBlockScalar($style, $chomping = '', $indentation = 0)
      *
      * @return bool Returns true if the next line is indented, false otherwise
      */
-    private function isNextLineIndented()
+    private function isNextLineIndented(): bool
     {
         $currentIndentation = $this->getCurrentLineIndentation();
         $EOF = !$this->moveToNextLine();
@@ -807,7 +807,7 @@ private function isNextLineIndented()
      *
      * @return bool Returns true if the current line is empty or if it is a comment line, false otherwise
      */
-    private function isCurrentLineEmpty()
+    private function isCurrentLineEmpty(): bool
     {
         return $this->isCurrentLineBlank() || $this->isCurrentLineComment();
     }
@@ -817,7 +817,7 @@ private function isCurrentLineEmpty()
      *
      * @return bool Returns true if the current line is blank, false otherwise
      */
-    private function isCurrentLineBlank()
+    private function isCurrentLineBlank(): bool
     {
         return '' == trim($this->currentLine, ' ');
     }
@@ -827,7 +827,7 @@ private function isCurrentLineBlank()
      *
      * @return bool Returns true if the current line is a comment line, false otherwise
      */
-    private function isCurrentLineComment()
+    private function isCurrentLineComment(): bool
     {
         //checking explicitly the first char of the trim is faster than loops or strpos
         $ltrimmedLine = ltrim($this->currentLine, ' ');
@@ -835,7 +835,7 @@ private function isCurrentLineComment()
         return '' !== $ltrimmedLine && $ltrimmedLine[0] === '#';
     }
 
-    private function isCurrentLineLastLineInDocument()
+    private function isCurrentLineLastLineInDocument(): bool
     {
         return ($this->offset + $this->currentLineNb) >= ($this->totalNumberOfLines - 1);
     }
@@ -847,7 +847,7 @@ private function isCurrentLineLastLineInDocument()
      *
      * @return string A cleaned up YAML string
      */
-    private function cleanup($value)
+    private function cleanup(string $value): string
     {
         $value = str_replace(array("\r\n", "\r"), "\n", $value);
 
@@ -883,7 +883,7 @@ private function cleanup($value)
      *
      * @return bool Returns true if the next line starts unindented collection, false otherwise
      */
-    private function isNextLineUnIndentedCollection()
+    private function isNextLineUnIndentedCollection(): bool
     {
         $currentIndentation = $this->getCurrentLineIndentation();
         $notEOF = $this->moveToNextLine();
@@ -908,7 +908,7 @@ private function isNextLineUnIndentedCollection()
      *
      * @return bool Returns true if the string is un-indented collection item, false otherwise
      */
-    private function isStringUnIndentedCollectionItem()
+    private function isStringUnIndentedCollectionItem(): bool
     {
         return '-' === rtrim($this->currentLine) || 0 === strpos($this->currentLine, '- ');
     }
@@ -918,7 +918,7 @@ private function isStringUnIndentedCollectionItem()
      *
      * @return bool
      */
-    private function isBlockScalarHeader()
+    private function isBlockScalarHeader(): bool
     {
         return (bool) self::preg_match('~'.self::BLOCK_SCALAR_HEADER_PATTERN.'$~', $this->currentLine);
     }
@@ -936,7 +936,7 @@ private function isBlockScalarHeader()
      *
      * @internal
      */
-    public static function preg_match($pattern, $subject, &$matches = null, $flags = 0, $offset = 0)
+    public static function preg_match(string $pattern, string $subject, array &$matches = null, int $flags = 0, int $offset = 0): int
     {
         if (false === $ret = preg_match($pattern, $subject, $matches, $flags, $offset)) {
             switch (preg_last_error()) {
@@ -971,7 +971,7 @@ public static function preg_match($pattern, $subject, &$matches = null, $flags =
      * Prevent values such as `!foo {quz: bar}` to be considered as
      * a mapping block.
      */
-    private function trimTag($value)
+    private function trimTag(string $value): string
     {
         if ('!' === $value[0]) {
             return ltrim(substr($value, 1, strcspn($value, " \r\n", 1)), ' ');
@@ -980,14 +980,14 @@ private function trimTag($value)
         return $value;
     }
 
-    private function getLineTag($value, $flags, $nextLineCheck = true)
+    private function getLineTag(string $value, int $flags, bool $nextLineCheck = true): ?string
     {
         if ('' === $value || '!' !== $value[0] || 1 !== self::preg_match('/^'.self::TAG_PATTERN.' *( +#.*)?$/', $value, $matches)) {
-            return;
+            return null;
         }
 
         if ($nextLineCheck && !$this->isNextLineIndented()) {
-            return;
+            return null;
         }
 
         $tag = substr($matches['tag'], 1);
diff --git a/src/Symfony/Component/Yaml/Tag/TaggedValue.php b/src/Symfony/Component/Yaml/Tag/TaggedValue.php
index 000c1d992cdee..4ea3406135999 100644
--- a/src/Symfony/Component/Yaml/Tag/TaggedValue.php
+++ b/src/Symfony/Component/Yaml/Tag/TaggedValue.php
@@ -20,27 +20,17 @@ final class TaggedValue
     private $tag;
     private $value;
 
-    /**
-     * @param string $tag
-     * @param mixed  $value
-     */
-    public function __construct($tag, $value)
+    public function __construct(string $tag, $value)
     {
         $this->tag = $tag;
         $this->value = $value;
     }
 
-    /**
-     * @return string
-     */
-    public function getTag()
+    public function getTag(): string
     {
         return $this->tag;
     }
 
-    /**
-     * @return mixed
-     */
     public function getValue()
     {
         return $this->value;
diff --git a/src/Symfony/Component/Yaml/Unescaper.php b/src/Symfony/Component/Yaml/Unescaper.php
index 6e863e12f2ad4..c9285acb49695 100644
--- a/src/Symfony/Component/Yaml/Unescaper.php
+++ b/src/Symfony/Component/Yaml/Unescaper.php
@@ -35,7 +35,7 @@ class Unescaper
      *
      * @return string The unescaped string
      */
-    public function unescapeSingleQuotedString($value)
+    public function unescapeSingleQuotedString(string $value): string
     {
         return str_replace('\'\'', '\'', $value);
     }
@@ -47,7 +47,7 @@ public function unescapeSingleQuotedString($value)
      *
      * @return string The unescaped string
      */
-    public function unescapeDoubleQuotedString($value)
+    public function unescapeDoubleQuotedString(string $value): string
     {
         $callback = function ($match) {
             return $this->unescapeCharacter($match[0]);
@@ -64,7 +64,7 @@ public function unescapeDoubleQuotedString($value)
      *
      * @return string The unescaped character
      */
-    private function unescapeCharacter($value)
+    private function unescapeCharacter(string $value): string
     {
         switch ($value[1]) {
             case '0':
@@ -125,7 +125,7 @@ private function unescapeCharacter($value)
      *
      * @return string The corresponding UTF-8 character
      */
-    private static function utf8chr($c)
+    private static function utf8chr(int $c): string
     {
         if (0x80 > $c %= 0x200000) {
             return chr($c);
diff --git a/src/Symfony/Component/Yaml/Yaml.php b/src/Symfony/Component/Yaml/Yaml.php
index 674982c33e9fb..992aac1ece700 100644
--- a/src/Symfony/Component/Yaml/Yaml.php
+++ b/src/Symfony/Component/Yaml/Yaml.php
@@ -50,7 +50,7 @@ class Yaml
      *
      * @throws ParseException If the YAML is not valid
      */
-    public static function parse($input, $flags = 0)
+    public static function parse(string $input, int $flags = 0)
     {
         $yaml = new Parser();
 
@@ -70,7 +70,7 @@ public static function parse($input, $flags = 0)
      *
      * @return string A YAML string representing the original PHP value
      */
-    public static function dump($input, $inline = 2, $indent = 4, $flags = 0)
+    public static function dump($input, int $inline = 2, int $indent = 4, int $flags = 0): string
     {
         $yaml = new Dumper($indent);