From 9e0ab2e52a90e5cd95229c1660cbd07f51a32f51 Mon Sep 17 00:00:00 2001
From: da-woods <dw-git@d-woods.co.uk>
Date: Thu, 18 Jun 2026 13:53:09 +0100
Subject: [PATCH] gh-141510 Document and test frozendict class matching
 behaviour (GH-150799)

Frozendict has `_Py_TPFLAGS_MATCH_SELF` set so works correctly
with the single-arg class matching. However it isn't documented
in the list of classes this works with and it isn't tested.

The test is some way below the other similar tests but anything
else would need a large renumbering.
(cherry picked from commit fd53ae113911e5a7d83c04b08623df824f9d5d70)

Co-authored-by: da-woods <dw-git@d-woods.co.uk>
---
 Doc/reference/compound_stmts.rst | 1 +
 Lib/test/test_patma.py           | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst
index 63baefd33e88c50..71bfb608dda7283 100644
--- a/Doc/reference/compound_stmts.rst
+++ b/Doc/reference/compound_stmts.rst
@@ -1172,6 +1172,7 @@ subject value:
    * :class:`bytes`
    * :class:`dict`
    * :class:`float`
+   * :class:`frozendict`
    * :class:`frozenset`
    * :class:`int`
    * :class:`list`
diff --git a/Lib/test/test_patma.py b/Lib/test/test_patma.py
index 29cce4ee6d271ff..e3aaea84ea7ce84 100644
--- a/Lib/test/test_patma.py
+++ b/Lib/test/test_patma.py
@@ -2852,6 +2852,15 @@ def test_patma_266(self):
         self.assertEqual(x, 0)
         self.assertEqual(y, 1)
 
+    def test_patma_frozendict_class_self(self):
+        x = frozendict()
+        match x:
+            case frozendict(z):
+                y = 0
+        self.assertEqual(x, frozendict())
+        self.assertEqual(y, 0)
+        self.assertIs(z, x)
+
     def test_patma_runtime_checkable_protocol(self):
         # Runtime-checkable protocol
         from typing import Protocol, runtime_checkable