diff --git a/src/Symfony/Bridge/Twig/AppVariable.php b/src/Symfony/Bridge/Twig/AppVariable.php
index eb9cec6dd9..4a22265908 100644
--- a/src/Symfony/Bridge/Twig/AppVariable.php
+++ b/src/Symfony/Bridge/Twig/AppVariable.php
@@ -111,8 +111,9 @@ class AppVariable
         if (null === $this->requestStack) {
             throw new \RuntimeException('The "app.session" variable is not available.');
         }
+        $request = $this->getRequest();
 
-        return ($request = $this->getRequest()) ? $request->getSession() : null;
+        return $request && $request->hasSession() ? $request->getSession() : null;
     }
 
     /**
@@ -154,8 +155,7 @@ class AppVariable
     public function getFlashes($types = null)
     {
         try {
-            $session = $this->getSession();
-            if (null === $session) {
+            if (null === $session = $this->getSession()) {
                 return [];
             }
         } catch (\RuntimeException $e) {
diff --git a/src/Symfony/Bundle/FrameworkBundle/Templating/GlobalVariables.php b/src/Symfony/Bundle/FrameworkBundle/Templating/GlobalVariables.php
index c3e0cbca4f..22b2551ac6 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Templating/GlobalVariables.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Templating/GlobalVariables.php
@@ -70,7 +70,9 @@ class GlobalVariables
      */
     public function getSession()
     {
-        return ($request = $this->getRequest()) ? $request->getSession() : null;
+        $request = $this->getRequest();
+
+        return $request && $request->hasSession() ? $request->getSession() : null;
     }
 
     /**
diff --git a/src/Symfony/Component/HttpKernel/ControllerMetadata/ArgumentMetadataFactory.php b/src/Symfony/Component/HttpKernel/ControllerMetadata/ArgumentMetadataFactory.php
index 0a25338818..44fe477945 100644
--- a/src/Symfony/Component/HttpKernel/ControllerMetadata/ArgumentMetadataFactory.php
+++ b/src/Symfony/Component/HttpKernel/ControllerMetadata/ArgumentMetadataFactory.php
@@ -42,10 +42,8 @@ final class ArgumentMetadataFactory implements ArgumentMetadataFactoryInterface
 
     /**
      * Returns an associated type to the given parameter if available.
-     *
-     * @return string|null
      */
-    private function getType(\ReflectionParameter $parameter, \ReflectionFunctionAbstract $function)
+    private function getType(\ReflectionParameter $parameter, \ReflectionFunctionAbstract $function): ?string
     {
         if (!$type = $parameter->getType()) {
             return null;
diff --git a/src/Symfony/Component/HttpKernel/Profiler/Profiler.php b/src/Symfony/Component/HttpKernel/Profiler/Profiler.php
index 39c181677e..f9d94b6f32 100644
--- a/src/Symfony/Component/HttpKernel/Profiler/Profiler.php
+++ b/src/Symfony/Component/HttpKernel/Profiler/Profiler.php
@@ -242,12 +242,9 @@ class Profiler implements ResetInterface
         return $this->collectors[$name];
     }
 
-    /**
-     * @return int|null
-     */
-    private function getTimestamp($value)
+    private function getTimestamp(?string $value): ?int
     {
-        if (null === $value || '' == $value) {
+        if (null === $value || '' === $value) {
             return null;
         }