diff --git a/extras/Hadrons/Modules/MSource/Wall.hpp b/extras/Hadrons/Modules/MSource/Wall.hpp
index 36a58ada..7a491fd2 100644
--- a/extras/Hadrons/Modules/MSource/Wall.hpp
+++ b/extras/Hadrons/Modules/MSource/Wall.hpp
@@ -22,6 +22,8 @@ public:
 template <typename FImpl>
 class TWall: public Module<WallPar>
 {
+public:
+    TYPE_ALIASES(FImpl,);
 public:
     // constructor
     TWall(const std::string name);