types: Avoid issues with objects override on subclasses

testapp/models.py

@@ -1,8 +1,11 @@
+from typing import TypeVar, ClassVar
+from typing_extensions import Self
+
 from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
 from django.db.models import ForeignKey, PositiveIntegerField, CharField
-from typedmodels.models import TypedModel
+from typedmodels.models import TypedModel, TypedModelManager
 
 
 class UniqueIdentifier(models.Model):
@@ -123,10 +126,14 @@ class Child2(Parent):
     pass
 
 
-class Employee(TypedModel):
+class EmployeeManager(TypedModelManager):
     pass
 
 
+class Employee(TypedModel):
+    objects: ClassVar[EmployeeManager] = EmployeeManager()
+
+
 class Developer(Employee):
     name = models.CharField(max_length=255, null=True)
 
@@ -139,5 +146,4 @@ class Manager(Employee):
 def typed_queryset() -> None:
     # This isn't actually called, but it's here for the mypy check to ensure that type hinting works correctly.
     queryset = Animal.objects.filter(pk=1)
-    reveal_type(queryset)  # QuerySet[Animal]
     queryset.filter(name="lynx")  # works, because Animal has this field

typedmodels/__init__.py

@@ -1 +1 @@
-__version__ = "0.15.0b2"
+__version__ = "0.15.0b3"

typedmodels/models.py

@@ -21,7 +21,7 @@
 
     reveal_type = print
 
-T = TypeVar("T", bound="TypedModel")
+T = TypeVar("T", bound="TypedModel", covariant=True)
 
 
 class TypedModelManager(models.Manager[T]):