diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
index e2a57177d20afb7..14fe70000b829ab 100755
--- a/Parser/asdl_c.py
+++ b/Parser/asdl_c.py
@@ -2274,7 +2274,7 @@ def generate_module_def(mod, metadata, f, internal_h):
             PyInterpreterState *interp = _PyInterpreterState_GET();
             struct ast_state *state = &interp->ast;
             assert(!state->finalized);
-            if (_PyOnceFlag_CallOnce(&state->once, (_Py_once_fn_t *)&init_types, state) < 0) {
+            if (_PyOnceFlag_CallOnce(&state->once, &init_types, state) < 0) {
                 return NULL;
             }
             return state;
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 49b6bf1d12b6fab..a8cc3847b3154ff 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -23,7 +23,7 @@ get_ast_state(void)
     PyInterpreterState *interp = _PyInterpreterState_GET();
     struct ast_state *state = &interp->ast;
     assert(!state->finalized);
-    if (_PyOnceFlag_CallOnce(&state->once, (_Py_once_fn_t *)&init_types, state) < 0) {
+    if (_PyOnceFlag_CallOnce(&state->once, &init_types, state) < 0) {
         return NULL;
     }
     return state;