python · vstinner · Mar 2, 2026 · Feb 22, 2026 · Feb 22, 2026 · Mar 2, 2026
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
@@ -2993,6 +2993,12 @@ def test_type_doc(self):
            A.__doc__ = doc
            self.assertEqual(A.__doc__, doc)

+    def test_type_frozendict(self):
+        A = type('A', (), frozendict({'x': 4, 'y': 2}))
+        self.assertEqual(A.x, 4)
+        self.assertEqual(A.y, 2)
+        self.assertEqual(A.__name__, 'A')
+
    def test_bad_args(self):
        with self.assertRaises(TypeError):
            type()

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-02-22-19-05-03.gh-issue-145118.bU6Sic.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-02-22-19-05-03.gh-issue-145118.bU6Sic.rst
@@ -0,0 +1 @@
+:func:`type` now accepts :class:`frozendict` as an argument.
@@ -4872,9 +4872,21 @@ type_new_get_slots(type_new_ctx *ctx, PyObject *dict)
 static PyTypeObject*
 type_new_init(type_new_ctx *ctx)
 {
-    PyObject *dict = PyDict_Copy(ctx->orig_dict);
-    if (dict == NULL) {
-        goto error;
+    PyObject *dict;
+    if (PyFrozenDict_Check(ctx->orig_dict)) {
+        dict = PyDict_New();
+        if (dict == NULL) {
+            goto error;
+        }
+        if (PyDict_Merge(dict, ctx->orig_dict, 1) < 0) {
+            goto error;
+        }
+    }
+    else {
+        dict = PyDict_Copy(ctx->orig_dict);
+        if (dict == NULL) {
+            goto error;
+        }
    }

    if (type_new_get_slots(ctx, dict) < 0) {
@@ -5037,13 +5049,19 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)

    /* Parse arguments: (name, bases, dict) */
    PyObject *name, *bases, *orig_dict;
-    if (!PyArg_ParseTuple(args, "UO!O!:type.__new__",
+    if (!PyArg_ParseTuple(args, "UO!O:type.__new__",
                          &name,
                          &PyTuple_Type, &bases,
-                          &PyDict_Type, &orig_dict))
+                          &orig_dict))
    {
        return NULL;
    }
+    if (!PyAnyDict_Check(orig_dict)) {
+        PyErr_Format(PyExc_TypeError,
+                     "type.__new__() argument 3 must be dict or frozendict, not %T",
+                     orig_dict);
+        return NULL;
+    }

    type_new_ctx ctx = {
        .metatype = metatype,
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		:func:`type` now accepts :class:`frozendict` as an argument.