diff --git a/ridlbe/c++11/templates/cli/hdr/struct_idl_traits_def.erb b/ridlbe/c++11/templates/cli/hdr/struct_idl_traits_def.erb
index 4892e0fc..87a27231 100644
--- a/ridlbe/c++11/templates/cli/hdr/struct_idl_traits_def.erb
+++ b/ridlbe/c++11/templates/cli/hdr/struct_idl_traits_def.erb
@@ -34,11 +34,12 @@ struct formatter<<%= scoped_cxxtype %>, OStrm_>
         << "object}"
 %       end
 %     else
-% unless _m.optional? || _m.external?
-        << "<%= _sep %><%= _m.cxxname %>=" << IDL::traits<<%= _m.scoped_cxxtype %>>::write(val_.<%= _m.cxxname %> ())
-% else
+% if _m.optional?
+        << "<%= _sep %><%= _m.cxxname %>="; if (val_.<%= _m.cxxname() %> ().has_value ()) { os_ << IDL::traits<<%= _m.scoped_cxxtype %>>::write(val_.<%= _m.cxxname %> ().value ()); } else { os_ << "std::nullopt"; } os_
+% elsif _m.external?
 %# TODO
-%#         << "<%= _sep %><%= _m.cxxname %>=" << (val_.<%= _m.cxxname() %> ().has_value () ? IDL::traits<<%= _m.scoped_cxxtype %>>::write(val_.<%= _m.cxxname %> ().value ()) : "<empty>")
+% else
+        << "<%= _sep %><%= _m.cxxname %>=" << IDL::traits<<%= _m.scoped_cxxtype %>>::write(val_.<%= _m.cxxname %> ())
 % end
 %     end
 %     _sep = ',' unless _sep
diff --git a/tests/idl4/optional/client.cpp b/tests/idl4/optional/client.cpp
index 71c79c4c..6638c975 100644
--- a/tests/idl4/optional/client.cpp
+++ b/tests/idl4/optional/client.cpp
@@ -16,5 +16,8 @@ int main (int /*argc*/, char* /*argv*/[])
   bar mybar;
 
   TAOX11_TEST_INFO << "mybar: " << mybar << std::endl;
+  mybar.z(6);
+  TAOX11_TEST_INFO << "mybar: " << mybar << std::endl;
+
   return retval;
 }
diff --git a/tests/idl4/optional/test.idl b/tests/idl4/optional/test.idl
index e47e3521..d24815a0 100644
--- a/tests/idl4/optional/test.idl
+++ b/tests/idl4/optional/test.idl
@@ -8,8 +8,9 @@
 struct bar
 {
   short x;
-  string y;
   @optional short z;
+  long z_long;
   @optional short a;
   @optional string opt_string;
+  string y;
 };