diff --git a/include/xo/expression/GlobalSymtab.hpp b/include/xo/expression/GlobalSymtab.hpp
index 6bdd88e0..1669df3b 100644
--- a/include/xo/expression/GlobalSymtab.hpp
+++ b/include/xo/expression/GlobalSymtab.hpp
@@ -39,7 +39,7 @@ namespace xo {
 
                 if (ix == global_map_.end()) {
                     /* not found */
-                    return bp<Variable>::from_native(nullptr);
+                    return bp<Variable>();
                 }
 
                 return ix->second;