fix handling of explicit objects annotation (typeddjango#2241) (#17)

Co-authored-by: Anthony Sottile <[email protected]>

Author: asottile-sentry

mypy_django_plugin/transformers/querysets.py

@@ -33,10 +33,14 @@ def determine_proper_manager_type(ctx: FunctionContext) -> MypyType:
     assert isinstance(default_return_type, Instance)
 
     outer_model_info = helpers.get_typechecker_api(ctx).scope.active_class()
-    if outer_model_info is None or not outer_model_info.has_base(fullnames.MODEL_CLASS_FULLNAME):
+    if (
+        outer_model_info is None
+        or not outer_model_info.has_base(fullnames.MODEL_CLASS_FULLNAME)
+        or outer_model_info.self_type is None
+    ):
         return default_return_type
 
-    return helpers.reparametrize_instance(default_return_type, [Instance(outer_model_info, [])])
+    return helpers.reparametrize_instance(default_return_type, [outer_model_info.self_type])
 
 
 def get_field_type_from_lookup(

tests/typecheck/managers/test_managers.yml

@@ -581,6 +581,7 @@
         -   path: myapp/models.py
             content: |
                 from typing import ClassVar, TypeVar
+                from typing_extensions import Self
                 from django.db import models
 
                 T = TypeVar("T", bound="MyModel")
@@ -595,7 +596,7 @@
                     pass
 
                 class MySubModel(MyModel):
-                    objects: ClassVar[MySubManager["MySubModel"]] = MySubManager()
+                    objects: ClassVar[MySubManager[Self]] = MySubManager()
 
 -   case: subclass_manager_without_type_parameters_disallow_any_generics
     main: |