diff --git a/src/gsi/gsi/gsiClassBase.cc b/src/gsi/gsi/gsiClassBase.cc
index 04e1b86a1..7ee9acd8f 100644
--- a/src/gsi/gsi/gsiClassBase.cc
+++ b/src/gsi/gsi/gsiClassBase.cc
@@ -679,7 +679,6 @@ ClassBase::classes_in_definition_order (const char *mod_name)
 
       if ((*c)->declaration () && (*c)->declaration () != *c && taken.find ((*c)->declaration ()) == taken.end ()) {
         //  can't produce this class yet - it's a reference to another class which is not produced yet.
-        tl_assert ((*c)->declaration () != 0);
         more_classes.push_back (*c);
         continue;
       }
diff --git a/src/gsi/gsi/gsiExpression.cc b/src/gsi/gsi/gsiExpression.cc
index 1c1d4ba3f..911d38fcc 100644
--- a/src/gsi/gsi/gsiExpression.cc
+++ b/src/gsi/gsi/gsiExpression.cc
@@ -1077,8 +1077,12 @@ initialize_expressions ()
   std::list<const gsi::ClassBase *> classes = gsi::ClassBase::classes_in_definition_order ();
   for (std::list<const gsi::ClassBase *>::const_iterator c = classes.begin (); c != classes.end (); ++c) {
 
-    //  Skip external classes
-    if ((*c)->is_external ()) {
+    //  we might encounter a child class which is a reference to a top-level class (e.g.
+    //  duplication of enums into child classes). In this case we should create a reference inside the
+    //  target class.
+    if ((*c)->declaration () != *c) {
+      tl_assert ((*c)->parent () != 0);  //  top-level classes should be merged
+      //  TODO: implement (see rba.cc:1544 for example)
       continue;
     }