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13 changes: 12 additions & 1 deletion Lib/test/test_type_aliases.py
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@
from test.typinganndata import mod_generics_cache

from typing import (
Callable, TypeAliasType, TypeVar, TypeVarTuple, ParamSpec, get_args,
Callable, TypeAliasType, TypeVar, TypeVarTuple, ParamSpec, Unpack, get_args,
)


Expand Down Expand Up @@ -317,6 +317,17 @@ def test_module(self):
self.assertEqual(mod_generics_cache.OldStyle.__module__,
mod_generics_cache.__name__)

def test_unpack(self):
type Alias = tuple[int, int]
unpacked = (*Alias,)[0]
self.assertEqual(unpacked, Unpack[Alias])

class Foo[*Ts]:
pass

x = Foo[str, *Alias]
self.assertEqual(x.__args__, (str, Unpack[Alias]))


# All these type aliases are used for pickling tests:
T = TypeVar('T')
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Add the ``tp_iter`` slot to :class:`typing.TypeAliasType` to allow star
unpacking.
13 changes: 7 additions & 6 deletions Objects/typevarobject.c
Original file line number Diff line number Diff line change
Expand Up @@ -385,7 +385,7 @@ caller(void)
}

static PyObject *
typevartuple_unpack(PyObject *tvt)
unpack(PyObject *self)
{
PyObject *typing = PyImport_ImportModule("typing");
if (typing == NULL) {
Expand All @@ -396,7 +396,7 @@ typevartuple_unpack(PyObject *tvt)
Py_DECREF(typing);
return NULL;
}
PyObject *unpacked = PyObject_GetItem(unpack, tvt);
PyObject *unpacked = PyObject_GetItem(unpack, self);
Py_DECREF(typing);
Py_DECREF(unpack);
return unpacked;
Expand Down Expand Up @@ -431,7 +431,7 @@ unpack_typevartuples(PyObject *params)
for (Py_ssize_t i = 0; i < n; i++) {
PyObject *param = PyTuple_GET_ITEM(params, i);
if (Py_IS_TYPE(param, tp)) {
PyObject *unpacked = typevartuple_unpack(param);
PyObject *unpacked = unpack(param);
if (unpacked == NULL) {
Py_DECREF(new_params);
return NULL;
Expand Down Expand Up @@ -1505,9 +1505,9 @@ typevartuple_dealloc(PyObject *self)
}

static PyObject *
typevartuple_iter(PyObject *self)
unpack_iter(PyObject *self)
{
PyObject *unpacked = typevartuple_unpack(self);
PyObject *unpacked = unpack(self);
if (unpacked == NULL) {
return NULL;
}
Expand Down Expand Up @@ -1760,7 +1760,7 @@ PyType_Slot typevartuple_slots[] = {
{Py_tp_methods, typevartuple_methods},
{Py_tp_getset, typevartuple_getset},
{Py_tp_new, typevartuple},
{Py_tp_iter, typevartuple_iter},
{Py_tp_iter, unpack_iter},
{Py_tp_repr, typevartuple_repr},
{Py_tp_dealloc, typevartuple_dealloc},
{Py_tp_alloc, PyType_GenericAlloc},
Expand Down Expand Up @@ -2134,6 +2134,7 @@ PyTypeObject _PyTypeAlias_Type = {
.tp_new = typealias_new,
.tp_free = PyObject_GC_Del,
.tp_traverse = (traverseproc)typealias_traverse,
.tp_iter = unpack_iter,
.tp_clear = (inquiry)typealias_clear,
.tp_repr = typealias_repr,
.tp_as_number = &typealias_as_number,
Expand Down
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