From 5d4321f1132e6e02adbe05e9ef031dde07a47fbf Mon Sep 17 00:00:00 2001
From: 55 <555>
Date: Mon, 21 Sep 2026 00:33:42 +0800
Subject: [PATCH] fix: ClassVar[Final[...]] collapses to Any instead of inner
 type (#21906)

Nested Final inside ClassVar on Python 3.13+ accepts the annotation
(no valid-type error) but the variable's type still collapsed to
AnyType(from_error), silently losing type information.

In try_analyze_special_unbound_type's FINAL_TYPE_NAMES branch, when
self.allow_final is True (i.e. the nested Final is legitimately accepted
in this context), preserve and return the inner type instead of falling
through to AnyType(from_error).

Regression guard: testFinalUsedWithClassVarAfterPy313PreservesType.
---
 mypy/typeanal.py                | 17 ++++++++++-------
 test-data/unit/check-final.test | 12 ++++++++++++
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/mypy/typeanal.py b/mypy/typeanal.py
index 8d500c54364ae..de3a4cf2da97e 100644
--- a/mypy/typeanal.py
+++ b/mypy/typeanal.py
@@ -639,13 +639,16 @@ def try_analyze_special_unbound_type(self, t: UnboundType, fullname: str) -> Typ
                     t,
                     code=codes.VALID_TYPE,
                 )
-            else:
-                if not self.allow_final:
-                    self.fail(
-                        "Final can be only used as an outermost qualifier in a variable annotation",
-                        t,
-                        code=codes.VALID_TYPE,
-                    )
+            elif not self.allow_final:
+                self.fail(
+                    "Final can be only used as an outermost qualifier in a variable annotation",
+                    t,
+                    code=codes.VALID_TYPE,
+                )
+            elif t.args:
+                # Nested Final[...] is accepted here (e.g. ClassVar[Final[...]] on 3.13+);
+                # preserve and return the inner type instead of collapsing to Any.
+                return self.anal_type(t.args[0])
             return AnyType(TypeOfAny.from_error)
         elif fullname in TUPLE_NAMES:
             # Tuple is special because it is involved in builtin import cycle
diff --git a/test-data/unit/check-final.test b/test-data/unit/check-final.test
index 8608962e00a42..b2ba8e0228a78 100644
--- a/test-data/unit/check-final.test
+++ b/test-data/unit/check-final.test
@@ -1134,6 +1134,18 @@ class A:
     b: ClassVar[Final[int]] = 1
     c: ClassVar[Final] = 1
 
+[case testFinalUsedWithClassVarAfterPy313PreservesType]
+# flags: --python-version 3.13
+# Nested Final inside ClassVar should preserve the inner type (#21906).
+from typing import ClassVar, Final, reveal_type
+
+class B: pass
+
+class A:
+    cv: ClassVar[Final[dict[type[B], A]] = {}
+
+reveal_type(A.cv)  # N: Revealed type is "builtins.dict[type[B], __main__.A"
+
 [case testFinalClassWithAbstractMethod]
 from typing import final
 from abc import ABC, abstractmethod