QuerySet.as_manager() support

test-data/typecheck/managers/querysets/test_as_manager.yml

@@ -0,0 +1,42 @@
+-   case: anonymous_queryset_from_as_manager_inside_model
+    main: |
+        from myapp.models import MyModel
+
+        reveal_type(MyModel.objects)  # N: Revealed type is 'myapp.models.MyQuerySet_AsManager_MyModel'
+        reveal_type(MyModel.objects.get())  # N: Revealed type is 'myapp.models.MyModel*'
+        reveal_type(MyModel.objects.queryset_method)  # N: Revealed type is 'def () -> builtins.int'
+        reveal_type(MyModel.objects.queryset_method())  # N: Revealed type is 'builtins.int'
+    installed_apps:
+        - myapp
+    files:
+        -   path: myapp/__init__.py
+        -   path: myapp/models.py
+            content: |
+                from django.db import models
+                class MyQuerySet(models.QuerySet):
+                    def queryset_method(self) -> int:
+                        pass
+                class MyModel(models.Model):
+                    objects = MyQuerySet.as_manager()
+
+
+-   case: as_manager_outside_model_parametrized_with_any
+    main: |
+        from myapp.models import NotModel, outside_objects
+        reveal_type(NotModel.objects)  # N: Revealed type is 'myapp.models.MyQuerySet_AsManager_Any'
+        reveal_type(NotModel.objects.get())  # N: Revealed type is 'Any'
+        reveal_type(outside_objects)  # N: Revealed type is 'myapp.models.MyQuerySet_AsManager_Any'
+        reveal_type(outside_objects.get())  # N: Revealed type is 'Any'
+    installed_apps:
+        - myapp
+    files:
+        -   path: myapp/__init__.py
+        -   path: myapp/models.py
+            content: |
+                from django.db import models
+                class MyQuerySet(models.QuerySet):
+                    def queryset_method(self) -> int:
+                        pass
+                outside_objects = MyQuerySet.as_manager()
+                class NotModel:
+                    objects = MyQuerySet.as_manager()