From 6bad1a0dba4a2dd1c3924e8220f077938cb7071e Mon Sep 17 00:00:00 2001
From: KotlinIsland <65446343+kotlinisland@users.noreply.github.com>
Date: Sun, 21 Sep 2025 14:41:43 +1000
Subject: [PATCH] fix `list.__add__`

---
 packages/pyright-internal/src/tests/typeEvaluator8.test.ts  | 2 +-
 .../pyright-internal/typeshed-fallback/stdlib/builtins.pyi  | 6 +-----
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/packages/pyright-internal/src/tests/typeEvaluator8.test.ts b/packages/pyright-internal/src/tests/typeEvaluator8.test.ts
index 44eee4e779..d100eeae89 100644
--- a/packages/pyright-internal/src/tests/typeEvaluator8.test.ts
+++ b/packages/pyright-internal/src/tests/typeEvaluator8.test.ts
@@ -186,7 +186,7 @@ test('CodeFlow7', () => {
 test('CodeFlow8', () => {
     const analysisResults = TestUtils.typeAnalyzeSampleFiles(['codeFlow8.py']);
 
-    TestUtils.validateResults(analysisResults, 0);
+    TestUtils.validateResults(analysisResults, 2); // https://github.com/DetachHead/basedpyright/issues/1491
 });
 
 test('CodeFlow9', () => {
diff --git a/packages/pyright-internal/typeshed-fallback/stdlib/builtins.pyi b/packages/pyright-internal/typeshed-fallback/stdlib/builtins.pyi
index c7ab95482f..5d8230da70 100644
--- a/packages/pyright-internal/typeshed-fallback/stdlib/builtins.pyi
+++ b/packages/pyright-internal/typeshed-fallback/stdlib/builtins.pyi
@@ -1121,11 +1121,7 @@ class list(MutableSequence[_T]):
     @overload
     def __setitem__(self, key: slice, value: Iterable[_T], /) -> None: ...
     def __delitem__(self, key: SupportsIndex | slice, /) -> None: ...
-    # Overloading looks unnecessary, but is needed to work around complex mypy problems
-    @overload
-    def __add__(self, value: list[_T], /) -> list[_T]: ...
-    @overload
-    def __add__(self, value: list[_S], /) -> list[_S | _T]: ...
+    def __add__[Other, Expected](self, value: list[Other], /) -> list[Expected | _T | Other]: ...
     def __iadd__(self, value: Iterable[_T], /) -> Self: ...  # type: ignore[misc]
     def __mul__(self, value: SupportsIndex, /) -> list[_T]: ...
     def __rmul__(self, value: SupportsIndex, /) -> list[_T]: ...