diff --git a/py/bc.c b/py/bc.c
index 9498b4f..3a8dc5e 100644
--- a/py/bc.c
+++ b/py/bc.c
@@ -62,7 +62,7 @@
 #elif MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_DETAILED
     nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
         "%s() takes %d positional arguments but %d were given",
-        mp_obj_fun_get_name(f), expected, given));
+        qstr_str(mp_obj_fun_get_name(f)), expected, given));
 #endif
 }