From 3be726ff31e4714b4b9f1578fff16d784ad2133d Mon Sep 17 00:00:00 2001
From: cherith <315844584+Cherith1222@users.noreply.github.com>
Date: Tue, 6 Oct 2026 11:47:24 +0800
Subject: [PATCH 1/2] Transform inner expression of StarExpr in TreeTransform

Functions using value-constrained type variables are checked as copies made by TreeTransform. visit_star_expr reused the original inner expression, so in '(*result,)' the NameExpr kept pointing at the original Var, which is never inferred because only the copies are checked. That produced a spurious has-type error and an Any tuple. Transform the inner expression and preserve the 'valid' flag.

Fixes #21693.

AI-assisted (Cursor). Not yet reviewed by a human.
---
 mypy/treetransform.py                   |  4 +++-
 test-data/unit/check-typevar-tuple.test | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/mypy/treetransform.py b/mypy/treetransform.py
index f33cba1e3c7a6..2c1ce2b19a738 100644
--- a/mypy/treetransform.py
+++ b/mypy/treetransform.py
@@ -450,7 +450,9 @@ def visit_match_stmt(self, o: MatchStmt) -> MatchStmt:
         )
 
     def visit_star_expr(self, node: StarExpr) -> StarExpr:
-        return StarExpr(node.expr)
+        new = StarExpr(self.expr(node.expr))
+        new.valid = node.valid
+        return new
 
     def visit_int_expr(self, node: IntExpr) -> IntExpr:
         return IntExpr(node.value)
diff --git a/test-data/unit/check-typevar-tuple.test b/test-data/unit/check-typevar-tuple.test
index 6d8c69a147a3f..0d4ed2cbbc81c 100644
--- a/test-data/unit/check-typevar-tuple.test
+++ b/test-data/unit/check-typevar-tuple.test
@@ -3255,3 +3255,21 @@ class K(Base):
 class Base: ...
 reveal_type(K.q)  # N: Revealed type is "builtins.list[tuple[builtins.bool, builtins.int, builtins.str]]"
 [builtins fixtures/tuple.pyi]
+
+[case testUnpackTypeVarTupleInFunctionWithConstrainedTypeVar]
+from typing import Generic, TypeVar, Tuple
+from typing_extensions import TypeVarTuple, Unpack
+
+T = TypeVar("T")
+P = TypeVar("P", int, str)
+Ts = TypeVarTuple("Ts")
+
+class Container(Generic[T, P]):
+    def foo(self) -> T: ...
+
+def f(container: Container[Tuple[Unpack[Ts]], P]) -> None:
+    result = container.foo()
+    reveal_type(result)  # N: Revealed type is "tuple[Unpack[Ts`-1]]"
+    y = (*result,)
+    reveal_type(y)  # N: Revealed type is "tuple[Unpack[Ts`-1]]"
+[builtins fixtures/tuple.pyi]
\ No newline at end of file

From b0c7abbb0ed32aaf73e94a054f106357765981ca Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 7 Oct 2026 07:28:23 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 test-data/unit/check-typevar-tuple.test | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test-data/unit/check-typevar-tuple.test b/test-data/unit/check-typevar-tuple.test
index 0d4ed2cbbc81c..655a89d8cc813 100644
--- a/test-data/unit/check-typevar-tuple.test
+++ b/test-data/unit/check-typevar-tuple.test
@@ -3272,4 +3272,4 @@ def f(container: Container[Tuple[Unpack[Ts]], P]) -> None:
     reveal_type(result)  # N: Revealed type is "tuple[Unpack[Ts`-1]]"
     y = (*result,)
     reveal_type(y)  # N: Revealed type is "tuple[Unpack[Ts`-1]]"
-[builtins fixtures/tuple.pyi]
\ No newline at end of file
+[builtins fixtures/tuple.pyi]