CallbackLambda: allow usage of lambda with no parameters on callbacks…

… that have at least one

includes/FastEngine/C_callback.inl

@@ -59,13 +59,38 @@ bool CallbackObjectFunctor<TObject, Types...>::check(void* ptr)
 
 //CallbackLambda
 
+namespace
+{
+
+template<typename T>
+struct lambda_traits : public lambda_traits<decltype(&T::operator())>
+{};
+
+template<typename ClassType, typename ReturnType, typename... Args>
+struct lambda_traits<ReturnType (ClassType::*)(Args...) const>
+{
+    enum : std::size_t
+    {
+        ArgCount = sizeof...(Args)
+    };
+};
+
+} // namespace
+
 template<class... Types>
 template<typename TLambda>
 CallbackLambda<Types...>::CallbackLambda(TLambda const& lambda) :
         g_lambda(new TLambda(lambda))
 {
-    this->g_executeLambda = [](void* lambdaPtr, Types... arguments) {
-        return (*reinterpret_cast<TLambda*>(lambdaPtr))(arguments...);
+    this->g_executeLambda = [](void* lambdaPtr, [[maybe_unused]] Types... arguments) {
+        if constexpr (lambda_traits<TLambda>::ArgCount != 0)
+        {
+            return (*reinterpret_cast<TLambda*>(lambdaPtr))(arguments...);
+        }
+        else
+        {
+            return (*reinterpret_cast<TLambda*>(lambdaPtr))();
+        }
     };
     this->g_deleteLambda = [](void* lambdaPtr) { delete reinterpret_cast<TLambda*>(lambdaPtr); };
 }