diff --git a/src/pocketpy.h b/src/pocketpy.h
index 70c0451e..ea9c5227 100644
--- a/src/pocketpy.h
+++ b/src/pocketpy.h
@@ -181,7 +181,7 @@ inline void init_builtins(VM* _vm) {
 
     _vm->bind_builtin_func<1>("dir", [](VM* vm, ArgsView args) {
         std::set<StrName> names;
-        if(args[0]->is_attr_valid()){
+        if(!is_tagged(args[0] && args[0]->is_attr_valid()){
             std::vector<StrName> keys = args[0]->attr().keys();
             names.insert(keys.begin(), keys.end());
         }
@@ -1110,4 +1110,4 @@ extern "C" {
         _pk_deleter_map[p] = [](void* p){ delete (pkpy::VM*)p; };
         return p;
     }
-}
\ No newline at end of file
+}