diff --git a/src/DependencyInjection/RockSolidMegaMenuExtension.php b/src/DependencyInjection/RockSolidMegaMenuExtension.php
index f11f03a..9ace15f 100644
--- a/src/DependencyInjection/RockSolidMegaMenuExtension.php
+++ b/src/DependencyInjection/RockSolidMegaMenuExtension.php
@@ -23,7 +23,7 @@ class RockSolidMegaMenuExtension extends Extension
 	/**
 	 * {@inheritdoc}
 	 */
-	public function getAlias()
+	public function getAlias(): string
 	{
 		return 'rocksolid_mega_menu';
 	}
diff --git a/src/RockSolidMegaMenuBundle.php b/src/RockSolidMegaMenuBundle.php
index 1ec984b..866d47e 100644
--- a/src/RockSolidMegaMenuBundle.php
+++ b/src/RockSolidMegaMenuBundle.php
@@ -9,6 +9,7 @@
 namespace MadeYourDay\RockSolidMegaMenu;
 
 use MadeYourDay\RockSolidMegaMenu\DependencyInjection\RockSolidMegaMenuExtension;
+use Symfony\Component\DependencyInjection\Extension\ExtensionInterface;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 
 /**
@@ -21,7 +22,7 @@ class RockSolidMegaMenuBundle extends Bundle
 	/**
 	 * {@inheritdoc}
 	 */
-	public function getContainerExtension()
+	public function getContainerExtension(): ?ExtensionInterface
 	{
 		return new RockSolidMegaMenuExtension();
 	}