diff --git a/src/variable.c b/src/variable.c
index 598850034..4f1c8bace 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -986,7 +986,7 @@ mrb_f_global_variables(mrb_state *mrb, mrb_value self)
 }
 
 static mrb_bool
-mrb_const_defined_0(mrb_state *mrb, mrb_value mod, mrb_sym id, mrb_bool exclude, mrb_bool recurse)
+const_defined_0(mrb_state *mrb, mrb_value mod, mrb_sym id, mrb_bool exclude, mrb_bool recurse)
 {
   struct RClass *klass = mrb_class_ptr(mod);
   struct RClass *tmp;
@@ -1012,13 +1012,13 @@ retry:
 MRB_API mrb_bool
 mrb_const_defined(mrb_state *mrb, mrb_value mod, mrb_sym id)
 {
-  return mrb_const_defined_0(mrb, mod, id, TRUE, TRUE);
+  return const_defined_0(mrb, mod, id, TRUE, TRUE);
 }
 
 MRB_API mrb_bool
 mrb_const_defined_at(mrb_state *mrb, mrb_value mod, mrb_sym id)
 {
-  return mrb_const_defined_0(mrb, mod, id, TRUE, FALSE);
+  return const_defined_0(mrb, mod, id, TRUE, FALSE);
 }
 
 MRB_API mrb_value