From 37d2ee49db02079e2862516d70d5e17c2fcbde89 Mon Sep 17 00:00:00 2001
From: hauntsaninja <hauntsaninja@gmail.com>
Date: Thu, 2 Apr 2026 13:24:12 -0700
Subject: [PATCH 1/3] Fix regression involving dict or on recursive dict

Fixes #21141
---
 mypy/constraints.py                       | 8 +++++---
 test-data/unit/check-recursive-types.test | 9 +++++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/mypy/constraints.py b/mypy/constraints.py
index df79fdae5456c..ad2ce12baf464 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -506,9 +506,11 @@ def handle_recursive_union(template: UnionType, actual: Type, direction: int) ->
     # the union in two parts, and try inferring sequentially.
     non_type_var_items = [t for t in template.items if not isinstance(t, TypeVarType)]
     type_var_items = [t for t in template.items if isinstance(t, TypeVarType)]
-    return infer_constraints(
-        UnionType.make_union(non_type_var_items), actual, direction
-    ) or infer_constraints(UnionType.make_union(type_var_items), actual, direction)
+    ret = infer_constraints(UnionType.make_union(non_type_var_items), actual, direction)
+    if ret or any(mypy.subtypes.is_subtype(t, actual) for t in non_type_var_items):
+        return ret
+    ret = infer_constraints(UnionType.make_union(type_var_items), actual, direction)
+    return ret
 
 
 def any_constraints(options: list[list[Constraint] | None], *, eager: bool) -> list[Constraint]:
diff --git a/test-data/unit/check-recursive-types.test b/test-data/unit/check-recursive-types.test
index 10333d113a689..c1ede22ac1aa5 100644
--- a/test-data/unit/check-recursive-types.test
+++ b/test-data/unit/check-recursive-types.test
@@ -1040,3 +1040,12 @@ def f(obj: OneClass) -> None:
     else:
         reveal_type(obj)  # N: Revealed type is "builtins.list[...]"
 [builtins fixtures/isinstancelist.pyi]
+
+[case testRecursiveDictOr]
+from typing_extensions import TypeAlias
+A: TypeAlias = "dict[str, A | int]"
+
+def f(d1: A, d2: A) -> None:
+    d3: A = {**d1, **d2}
+    d4: A = d1 | d2
+[builtins fixtures/dict-full.pyi]

From 7f48f4dfd3ac769a4533d46632dca2e57bdb419f Mon Sep 17 00:00:00 2001
From: hauntsaninja <hauntsaninja@gmail.com>
Date: Thu, 2 Apr 2026 14:11:02 -0700
Subject: [PATCH 2/3] fix fixture

---
 test-data/unit/fixtures/dict-full.pyi | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/test-data/unit/fixtures/dict-full.pyi b/test-data/unit/fixtures/dict-full.pyi
index 4f4097b77788a..fef0d3c9624ad 100644
--- a/test-data/unit/fixtures/dict-full.pyi
+++ b/test-data/unit/fixtures/dict-full.pyi
@@ -8,6 +8,7 @@ from typing import (
 )
 
 T = TypeVar('T')
+T1 = TypeVar('T1')
 T2 = TypeVar('T2')
 KT = TypeVar('KT')
 VT = TypeVar('VT')
@@ -39,15 +40,8 @@ class dict(Mapping[KT, VT]):
     def get(self, key: KT, default: T, /) -> Union[VT, T]: pass
     def __len__(self) -> int: ...
 
-    # This was actually added in 3.9:
-    @overload
-    def __or__(self, __value: dict[KT, VT]) -> dict[KT, VT]: ...
-    @overload
-    def __or__(self, __value: dict[T, T2]) -> dict[Union[KT, T], Union[VT, T2]]: ...
-    @overload
-    def __ror__(self, __value: dict[KT, VT]) -> dict[KT, VT]: ...
-    @overload
-    def __ror__(self, __value: dict[T, T2]) -> dict[Union[KT, T], Union[VT, T2]]: ...
+    def __or__(self, value: dict[T1, T2], /) -> dict[KT | T1, VT | T2]: ...
+    def __ror__(self, value: dict[T1, T2], /) -> dict[KT | T1, VT | T2]: ...
     # dict.__ior__ should be kept roughly in line with MutableMapping.update()
     @overload  # type: ignore[misc]
     def __ior__(self, __value: _typeshed.SupportsKeysAndGetItem[KT, VT]) -> Self: ...

From 31a61a258221ffdbc918a8d8a144e707d599fa3c Mon Sep 17 00:00:00 2001
From: hauntsaninja <hauntsaninja@gmail.com>
Date: Thu, 2 Apr 2026 14:39:03 -0700
Subject: [PATCH 3/3] use is_same_type for symmetry

---
 mypy/constraints.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mypy/constraints.py b/mypy/constraints.py
index ad2ce12baf464..1176d144511cf 100644
--- a/mypy/constraints.py
+++ b/mypy/constraints.py
@@ -507,7 +507,7 @@ def handle_recursive_union(template: UnionType, actual: Type, direction: int) ->
     non_type_var_items = [t for t in template.items if not isinstance(t, TypeVarType)]
     type_var_items = [t for t in template.items if isinstance(t, TypeVarType)]
     ret = infer_constraints(UnionType.make_union(non_type_var_items), actual, direction)
-    if ret or any(mypy.subtypes.is_subtype(t, actual) for t in non_type_var_items):
+    if ret or any(mypy.subtypes.is_same_type(t, actual) for t in non_type_var_items):
         return ret
     ret = infer_constraints(UnionType.make_union(type_var_items), actual, direction)
     return ret