From 251b58ee76d668218c65e52a04126f1408d6e16f Mon Sep 17 00:00:00 2001
From: Jonathan Dung <jonathandung@yahoo.com>
Date: Sat, 27 Jun 2026 15:39:08 +0800
Subject: [PATCH 1/3] commit

---
 stdlib/builtins.pyi | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
index 096d440ac38c..c02e206c7bad 100644
--- a/stdlib/builtins.pyi
+++ b/stdlib/builtins.pyi
@@ -1821,7 +1821,35 @@ def iter(object: Callable[[], _T], sentinel: object, /) -> Iterator[_T]: ...
 
 _ClassInfo: TypeAlias = type | types.UnionType | tuple[_ClassInfo, ...]
 
+@overload
+def isinstance(obj: object, class_or_tuple: type[_T] | tuple[type[_T]], /) -> TypeIs[_T]: ...
+@overload
+def isinstance(
+    obj: object, class_or_tuple: tuple[type[_T], type[_T1]], /
+) -> TypeIs[_T | _T1]: ...
+@overload
+def isinstance(
+    obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[T2]], /
+) -> TypeIs[T | T1 | T2]: ...
+@overload
+def isinstance(
+    obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3]], /
+) -> TypeIs[_T | _T1 | _T2 | _T3]: ...
+@overload
+def isinstance(
+    obj: object,
+    class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3], type[_T4]],
+    /,
+) -> TypeIs[_T | _T1 | _T2 | _T3 | _T4]: ...
+@overload
+def isinstance(
+    obj: object,
+    class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3], type[_T4], type[_T5]],
+    /,
+) -> TypeIs[_T | _T1 | _T2 | _T3 | _T4 | _T5]: ...
+@overload
 def isinstance(obj: object, class_or_tuple: _ClassInfo, /) -> bool: ...
+
 def issubclass(cls: type, class_or_tuple: _ClassInfo, /) -> bool: ...
 def len(obj: Sized, /) -> int: ...
 

From f751531e2caf73376c42ae95b52fac7a106ec77c Mon Sep 17 00:00:00 2001
From: Jonathan Dung <jonathandung@yahoo.com>
Date: Sat, 27 Jun 2026 15:42:22 +0800
Subject: [PATCH 2/3] hotfix

---
 stdlib/builtins.pyi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
index c02e206c7bad..8c46c650478a 100644
--- a/stdlib/builtins.pyi
+++ b/stdlib/builtins.pyi
@@ -1829,8 +1829,8 @@ def isinstance(
 ) -> TypeIs[_T | _T1]: ...
 @overload
 def isinstance(
-    obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[T2]], /
-) -> TypeIs[T | T1 | T2]: ...
+    obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2]], /
+) -> TypeIs[_T | _T1 | _T2]: ...
 @overload
 def isinstance(
     obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3]], /

From 740e917bd0ac62072d1587ddad2e7ae65eb4f821 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Sat, 27 Jun 2026 07:44:52 +0000
Subject: [PATCH 3/3] [pre-commit.ci] auto fixes from pre-commit.com hooks

---
 stdlib/builtins.pyi | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/stdlib/builtins.pyi b/stdlib/builtins.pyi
index 8c46c650478a..c227d8e7ee29 100644
--- a/stdlib/builtins.pyi
+++ b/stdlib/builtins.pyi
@@ -1824,28 +1824,20 @@ _ClassInfo: TypeAlias = type | types.UnionType | tuple[_ClassInfo, ...]
 @overload
 def isinstance(obj: object, class_or_tuple: type[_T] | tuple[type[_T]], /) -> TypeIs[_T]: ...
 @overload
-def isinstance(
-    obj: object, class_or_tuple: tuple[type[_T], type[_T1]], /
-) -> TypeIs[_T | _T1]: ...
+def isinstance(obj: object, class_or_tuple: tuple[type[_T], type[_T1]], /) -> TypeIs[_T | _T1]: ...
 @overload
-def isinstance(
-    obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2]], /
-) -> TypeIs[_T | _T1 | _T2]: ...
+def isinstance(obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2]], /) -> TypeIs[_T | _T1 | _T2]: ...
 @overload
 def isinstance(
     obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3]], /
 ) -> TypeIs[_T | _T1 | _T2 | _T3]: ...
 @overload
 def isinstance(
-    obj: object,
-    class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3], type[_T4]],
-    /,
+    obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3], type[_T4]], /
 ) -> TypeIs[_T | _T1 | _T2 | _T3 | _T4]: ...
 @overload
 def isinstance(
-    obj: object,
-    class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3], type[_T4], type[_T5]],
-    /,
+    obj: object, class_or_tuple: tuple[type[_T], type[_T1], type[_T2], type[_T3], type[_T4], type[_T5]], /
 ) -> TypeIs[_T | _T1 | _T2 | _T3 | _T4 | _T5]: ...
 @overload
 def isinstance(obj: object, class_or_tuple: _ClassInfo, /) -> bool: ...