[3.10] bpo-44652: Preserve natural order of args in the union type. (GH-27185) (GH-27190)
(cherry picked from commit 0cd2d51aadcd2a0c0739a5df0a6235d64f35619e)
Automerge-Triggered-By: GH:ambv
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index f3e0aa6..15cd6c5 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -257,8 +257,8 @@ dedup_and_flatten_args(PyObject* args)
for (Py_ssize_t i = 0; i < arg_length; i++) {
int is_duplicate = 0;
PyObject* i_element = PyTuple_GET_ITEM(args, i);
- for (Py_ssize_t j = i + 1; j < arg_length; j++) {
- PyObject* j_element = PyTuple_GET_ITEM(args, j);
+ for (Py_ssize_t j = 0; j < added_items; j++) {
+ PyObject* j_element = PyTuple_GET_ITEM(new_args, j);
int is_ga = PyObject_TypeCheck(i_element, &Py_GenericAliasType) &&
PyObject_TypeCheck(j_element, &Py_GenericAliasType);
// RichCompare to also deduplicate GenericAlias types (slower)