1 files changed, 2 insertions, 1 deletions
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 33dc3db..54957db 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -1221,7 +1221,7 @@ static PyType_Spec MinimalMetaclass_spec = {
 
 static PyType_Spec MinimalType_spec = {
     .name = "_testcapi.MinimalSpecType",
-    .basicsize = sizeof(PyObject),
+    .basicsize = 0,  // Updated later
     .flags = Py_TPFLAGS_DEFAULT,
     .slots = empty_type_slots,
 };
@@ -1245,6 +1245,7 @@ test_from_spec_metatype_inheritance(PyObject *self, PyObject *Py_UNUSED(ignored)
         goto finally;
     }
 
+    MinimalType_spec.basicsize = (int)(((PyTypeObject*)class)->tp_basicsize);
     new = PyType_FromSpecWithBases(&MinimalType_spec, class);
     if (new == NULL) {
         goto finally;