diff --git a/src/Symfony/Component/Routing/Generator/CompiledUrlGenerator.php b/src/Symfony/Component/Routing/Generator/CompiledUrlGenerator.php
index 41cd5893ae2f..8c489f8d4c02 100644
--- a/src/Symfony/Component/Routing/Generator/CompiledUrlGenerator.php
+++ b/src/Symfony/Component/Routing/Generator/CompiledUrlGenerator.php
@@ -31,7 +31,7 @@ public function __construct(array $compiledRoutes, RequestContext $context, Logg
         $this->defaultLocale = $defaultLocale;
     }
 
-    public function generate($name, $parameters = [], $referenceType = self::ABSOLUTE_PATH)
+    public function generate(string $name, array $parameters = [], int $referenceType = self::ABSOLUTE_PATH)
     {
         $locale = $parameters['_locale']
             ?? $this->context->getParameter('_locale')
diff --git a/src/Symfony/Component/Routing/Generator/ConfigurableRequirementsInterface.php b/src/Symfony/Component/Routing/Generator/ConfigurableRequirementsInterface.php
index 2e5dc5325bdd..568f7f775300 100644
--- a/src/Symfony/Component/Routing/Generator/ConfigurableRequirementsInterface.php
+++ b/src/Symfony/Component/Routing/Generator/ConfigurableRequirementsInterface.php
@@ -40,10 +40,8 @@ interface ConfigurableRequirementsInterface
     /**
      * Enables or disables the exception on incorrect parameters.
      * Passing null will deactivate the requirements check completely.
-     *
-     * @param bool|null $enabled
      */
-    public function setStrictRequirements($enabled);
+    public function setStrictRequirements(?bool $enabled);
 
     /**
      * Returns whether to throw an exception on incorrect parameters.
diff --git a/src/Symfony/Component/Routing/Generator/UrlGenerator.php b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
index e5811c73a842..6623578aaa5c 100644
--- a/src/Symfony/Component/Routing/Generator/UrlGenerator.php
+++ b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
@@ -108,9 +108,9 @@ public function getContext()
     /**
      * {@inheritdoc}
      */
-    public function setStrictRequirements($enabled)
+    public function setStrictRequirements(?bool $enabled)
     {
-        $this->strictRequirements = null === $enabled ? null : (bool) $enabled;
+        $this->strictRequirements = $enabled;
     }
 
     /**
@@ -124,7 +124,7 @@ public function isStrictRequirements()
     /**
      * {@inheritdoc}
      */
-    public function generate($name, $parameters = [], $referenceType = self::ABSOLUTE_PATH)
+    public function generate(string $name, array $parameters = [], int $referenceType = self::ABSOLUTE_PATH)
     {
         $route = null;
         $locale = $parameters['_locale']
@@ -155,7 +155,7 @@ public function generate($name, $parameters = [], $referenceType = self::ABSOLUT
      * @throws InvalidParameterException           When a parameter value for a placeholder is not correct because
      *                                             it does not match the requirement
      */
-    protected function doGenerate($variables, $defaults, $requirements, $tokens, $parameters, $name, $referenceType, $hostTokens, array $requiredSchemes = [])
+    protected function doGenerate(array $variables, array $defaults, array $requirements, array $tokens, array $parameters, string $name, int $referenceType, array $hostTokens, array $requiredSchemes = [])
     {
         $variables = array_flip($variables);
         $mergedParams = array_replace($defaults, $this->context->getParameters(), $parameters);
@@ -321,7 +321,7 @@ protected function doGenerate($variables, $defaults, $requirements, $tokens, $pa
      *
      * @return string The relative target path
      */
-    public static function getRelativePath($basePath, $targetPath)
+    public static function getRelativePath(string $basePath, string $targetPath)
     {
         if ($basePath === $targetPath) {
             return '';
diff --git a/src/Symfony/Component/Routing/Generator/UrlGeneratorInterface.php b/src/Symfony/Component/Routing/Generator/UrlGeneratorInterface.php
index f7d37b2564b1..5890ffa55eb8 100644
--- a/src/Symfony/Component/Routing/Generator/UrlGeneratorInterface.php
+++ b/src/Symfony/Component/Routing/Generator/UrlGeneratorInterface.php
@@ -71,10 +71,6 @@ interface UrlGeneratorInterface extends RequestContextAwareInterface
      *
      * The special parameter _fragment will be used as the document fragment suffixed to the final URL.
      *
-     * @param string $name          The name of the route
-     * @param mixed  $parameters    An array of parameters
-     * @param int    $referenceType The type of reference to be generated (one of the constants)
-     *
      * @return string The generated URL
      *
      * @throws RouteNotFoundException              If the named route doesn't exist
@@ -82,5 +78,5 @@ interface UrlGeneratorInterface extends RequestContextAwareInterface
      * @throws InvalidParameterException           When a parameter value for a placeholder is not correct because
      *                                             it does not match the requirement
      */
-    public function generate($name, $parameters = [], $referenceType = self::ABSOLUTE_PATH);
+    public function generate(string $name, array $parameters = [], int $referenceType = self::ABSOLUTE_PATH);
 }
diff --git a/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcher.php b/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcher.php
index eb7bec7f3442..3cd7c81a6cb1 100644
--- a/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcher.php
+++ b/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcher.php
@@ -22,7 +22,7 @@ abstract class RedirectableUrlMatcher extends UrlMatcher implements Redirectable
     /**
      * {@inheritdoc}
      */
-    public function match($pathinfo)
+    public function match(string $pathinfo)
     {
         try {
             return parent::match($pathinfo);
diff --git a/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcherInterface.php b/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcherInterface.php
index 7c27bc879653..144945d96796 100644
--- a/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcherInterface.php
+++ b/src/Symfony/Component/Routing/Matcher/RedirectableUrlMatcherInterface.php
@@ -27,5 +27,5 @@ interface RedirectableUrlMatcherInterface
      *
      * @return array An array of parameters
      */
-    public function redirect($path, $route, $scheme = null);
+    public function redirect(string $path, string $route, string $scheme = null);
 }
diff --git a/src/Symfony/Component/Routing/Matcher/UrlMatcher.php b/src/Symfony/Component/Routing/Matcher/UrlMatcher.php
index dca1d6366fa0..adc0a891b2ae 100644
--- a/src/Symfony/Component/Routing/Matcher/UrlMatcher.php
+++ b/src/Symfony/Component/Routing/Matcher/UrlMatcher.php
@@ -81,7 +81,7 @@ public function getContext()
     /**
      * {@inheritdoc}
      */
-    public function match($pathinfo)
+    public function match(string $pathinfo)
     {
         $this->allow = $this->allowSchemes = [];
 
diff --git a/src/Symfony/Component/Routing/Matcher/UrlMatcherInterface.php b/src/Symfony/Component/Routing/Matcher/UrlMatcherInterface.php
index 17f1f97b3b47..24f23e381fa5 100644
--- a/src/Symfony/Component/Routing/Matcher/UrlMatcherInterface.php
+++ b/src/Symfony/Component/Routing/Matcher/UrlMatcherInterface.php
@@ -37,5 +37,5 @@ interface UrlMatcherInterface extends RequestContextAwareInterface
      * @throws ResourceNotFoundException If the resource could not be found
      * @throws MethodNotAllowedException If the resource was found but the request method is not allowed
      */
-    public function match($pathinfo);
+    public function match(string $pathinfo);
 }
diff --git a/src/Symfony/Component/Routing/Router.php b/src/Symfony/Component/Routing/Router.php
index 63c802d03e0d..a24b193d96aa 100644
--- a/src/Symfony/Component/Routing/Router.php
+++ b/src/Symfony/Component/Routing/Router.php
@@ -159,12 +159,11 @@ public function setOptions(array $options)
     /**
      * Sets an option.
      *
-     * @param string $key   The key
-     * @param mixed  $value The value
+     * @param mixed $value The value
      *
      * @throws \InvalidArgumentException
      */
-    public function setOption($key, $value)
+    public function setOption(string $key, $value)
     {
         if (!\array_key_exists($key, $this->options)) {
             throw new \InvalidArgumentException(sprintf('The Router does not support the "%s" option.', $key));
@@ -176,13 +175,11 @@ public function setOption($key, $value)
     /**
      * Gets an option value.
      *
-     * @param string $key The key
-     *
      * @return mixed The value
      *
      * @throws \InvalidArgumentException
      */
-    public function getOption($key)
+    public function getOption(string $key)
     {
         if (!\array_key_exists($key, $this->options)) {
             throw new \InvalidArgumentException(sprintf('The Router does not support the "%s" option.', $key));
@@ -237,7 +234,7 @@ public function setConfigCacheFactory(ConfigCacheFactoryInterface $configCacheFa
     /**
      * {@inheritdoc}
      */
-    public function generate($name, $parameters = [], $referenceType = self::ABSOLUTE_PATH)
+    public function generate(string $name, array $parameters = [], int $referenceType = self::ABSOLUTE_PATH)
     {
         return $this->getGenerator()->generate($name, $parameters, $referenceType);
     }
@@ -245,7 +242,7 @@ public function generate($name, $parameters = [], $referenceType = self::ABSOLUT
     /**
      * {@inheritdoc}
      */
-    public function match($pathinfo)
+    public function match(string $pathinfo)
     {
         return $this->getMatcher()->match($pathinfo);
     }
diff --git a/src/Symfony/Component/Routing/Tests/Fixtures/RedirectableUrlMatcher.php b/src/Symfony/Component/Routing/Tests/Fixtures/RedirectableUrlMatcher.php
index 79ae1cce54ca..5a950942c8e9 100644
--- a/src/Symfony/Component/Routing/Tests/Fixtures/RedirectableUrlMatcher.php
+++ b/src/Symfony/Component/Routing/Tests/Fixtures/RedirectableUrlMatcher.php
@@ -19,7 +19,7 @@
  */
 class RedirectableUrlMatcher extends UrlMatcher implements RedirectableUrlMatcherInterface
 {
-    public function redirect($path, $route, $scheme = null)
+    public function redirect(string $path, string $route, string $scheme = null)
     {
         return [
             '_controller' => 'Some controller reference...',
diff --git a/src/Symfony/Component/Routing/Tests/Matcher/CompiledRedirectableUrlMatcherTest.php b/src/Symfony/Component/Routing/Tests/Matcher/CompiledRedirectableUrlMatcherTest.php
index 7fb7dfef9e97..1b3d7b66e8d2 100644
--- a/src/Symfony/Component/Routing/Tests/Matcher/CompiledRedirectableUrlMatcherTest.php
+++ b/src/Symfony/Component/Routing/Tests/Matcher/CompiledRedirectableUrlMatcherTest.php
@@ -33,7 +33,7 @@ protected function getUrlMatcher(RouteCollection $routes, RequestContext $contex
 
 class TestCompiledRedirectableUrlMatcher extends CompiledUrlMatcher implements RedirectableUrlMatcherInterface
 {
-    public function redirect($path, $route, $scheme = null)
+    public function redirect(string $path, string $route, string $scheme = null)
     {
         return [];
     }
diff --git a/src/Symfony/Component/Routing/Tests/Matcher/Dumper/CompiledUrlMatcherDumperTest.php b/src/Symfony/Component/Routing/Tests/Matcher/Dumper/CompiledUrlMatcherDumperTest.php
index ad9c8376f72c..87a453b4ef6f 100644
--- a/src/Symfony/Component/Routing/Tests/Matcher/Dumper/CompiledUrlMatcherDumperTest.php
+++ b/src/Symfony/Component/Routing/Tests/Matcher/Dumper/CompiledUrlMatcherDumperTest.php
@@ -489,7 +489,7 @@ public function testGenerateDumperMatcherWithObject()
 
 class TestCompiledUrlMatcher extends CompiledUrlMatcher implements RedirectableUrlMatcherInterface
 {
-    public function redirect($path, $route, $scheme = null)
+    public function redirect(string $path, string $route, string $scheme = null)
     {
         return [];
     }