diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index 2156ca0..ccf5f8e 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -35,7 +35,7 @@
 PyTypeObject PyModuleDef_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "moduledef",                                /* tp_name */
-    sizeof(struct PyModuleDef),                 /* tp_size */
+    sizeof(struct PyModuleDef),                 /* tp_basicsize */
     0,                                          /* tp_itemsize */
 };
 
@@ -790,7 +790,7 @@
 PyTypeObject PyModule_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "module",                                   /* tp_name */
-    sizeof(PyModuleObject),                     /* tp_size */
+    sizeof(PyModuleObject),                     /* tp_basicsize */
     0,                                          /* tp_itemsize */
     (destructor)module_dealloc,                 /* tp_dealloc */
     0,                                          /* tp_print */