diff --git a/DependencyInjection/Compiler/RegisterMappingPass.php b/DependencyInjection/Compiler/RegisterMappingPass.php
index 84b9cfb1..a24a879b 100644
--- a/DependencyInjection/Compiler/RegisterMappingPass.php
+++ b/DependencyInjection/Compiler/RegisterMappingPass.php
@@ -17,7 +17,7 @@ class RegisterMappingPass implements CompilerPassInterface
     /**
      * {@inheritdoc}
      */
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         $storage = $container->getParameter('lexik_translation.storage');
 
diff --git a/DependencyInjection/Compiler/TranslatorPass.php b/DependencyInjection/Compiler/TranslatorPass.php
index 461c1cb3..2c4f8740 100644
--- a/DependencyInjection/Compiler/TranslatorPass.php
+++ b/DependencyInjection/Compiler/TranslatorPass.php
@@ -20,7 +20,7 @@ class TranslatorPass implements CompilerPassInterface
     /**
      * {@inheritdoc}
      */
-    public function process(ContainerBuilder $container)
+    public function process(ContainerBuilder $container): void
     {
         // loaders
         $loaders = [];