From 4784b4d38846fd7f945592c1846f1cc016111f7d Mon Sep 17 00:00:00 2001
From: Fidget-Spinner <28750310+Fidget-Spinner@users.noreply.github.com>
Date: Sat, 5 Dec 2020 22:36:43 +0800
Subject: [PATCH 1/2] raise typeerror when kwargs are passed into genericalias
 rather than crash

---
 .../Core and Builtins/2020-12-05-22-34-47.bpo-42576.lEeEl7.rst | 3 +++
 Objects/genericaliasobject.c                                   | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2020-12-05-22-34-47.bpo-42576.lEeEl7.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-12-05-22-34-47.bpo-42576.lEeEl7.rst b/Misc/NEWS.d/next/Core and Builtins/2020-12-05-22-34-47.bpo-42576.lEeEl7.rst
new file mode 100644
index 00000000000000..7290b47dcc15ca
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-12-05-22-34-47.bpo-42576.lEeEl7.rst	
@@ -0,0 +1,3 @@
+``types.GenericAlias`` will now raise a ``TypeError`` when attempting to
+initialize with a keyword argument.  Previously, this would cause the
+interpreter to crash.  Patch by Ken Jin.
diff --git a/Objects/genericaliasobject.c b/Objects/genericaliasobject.c
index 6102e05c165c5d..51a12377b7e308 100644
--- a/Objects/genericaliasobject.c
+++ b/Objects/genericaliasobject.c
@@ -567,7 +567,7 @@ static PyGetSetDef ga_properties[] = {
 static PyObject *
 ga_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 {
-    if (!_PyArg_NoKwnames("GenericAlias", kwds)) {
+    if (!_PyArg_NoKeywords("GenericAlias", kwds)) {
         return NULL;
     }
     if (!_PyArg_CheckPositional("GenericAlias", PyTuple_GET_SIZE(args), 2, 2)) {

From f7a915982dfd6dde87a9319c9c1591f5559452ef Mon Sep 17 00:00:00 2001
From: Fidget-Spinner <28750310+Fidget-Spinner@users.noreply.github.com>
Date: Sat, 5 Dec 2020 22:41:31 +0800
Subject: [PATCH 2/2] add tests

---
 Lib/test/test_genericalias.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Lib/test/test_genericalias.py b/Lib/test/test_genericalias.py
index 912fb33af1a21b..c113e538248e9c 100644
--- a/Lib/test/test_genericalias.py
+++ b/Lib/test/test_genericalias.py
@@ -302,6 +302,11 @@ def test_weakref(self):
                 alias = t[int]
                 self.assertEqual(ref(alias)(), alias)
 
+    def test_no_kwargs(self):
+        # bpo-42576
+        with self.assertRaises(TypeError):
+            GenericAlias(bad=float)
+
 
 if __name__ == "__main__":
     unittest.main()