allow to specify QuerySet with one parameter

mypy_django_plugin/django/context.py

@@ -1,27 +1,25 @@
 import os
 from collections import defaultdict
 from contextlib import contextmanager
-from typing import TYPE_CHECKING, Dict, Iterator, List, Optional, Tuple, Type
+from typing import Dict, Iterator, List, Optional, TYPE_CHECKING, Tuple, Type
 
-from mypy.nodes import TypeInfo
-
-from django.contrib.postgres.fields import ArrayField
 from django.core.exceptions import FieldError
 from django.db.models.base import Model
-from django.db.models.fields import AutoField, CharField, Field
 from django.db.models.fields.related import ForeignKey, RelatedField
 from django.db.models.fields.reverse_related import ForeignObjectRel
 from django.db.models.sql.query import Query
 from django.utils.functional import cached_property
 from mypy.checker import TypeChecker
-from mypy.types import Instance, AnyType, TypeOfAny
-from mypy.types import Type as MypyType
+from mypy.nodes import TypeInfo
+from mypy.types import AnyType, Instance, Type as MypyType, TypeOfAny
 
+from django.contrib.postgres.fields import ArrayField
+from django.db.models.fields import AutoField, CharField, Field
 from mypy_django_plugin.lib import helpers
 
 if TYPE_CHECKING:
     from django.apps.registry import Apps  # noqa: F401
-    from django.conf import LazySettings
+    from django.conf import LazySettings  # noqa: F401
 
 
 @contextmanager

mypy_django_plugin/main.py

@@ -6,9 +6,7 @@ from django.db.models.fields.related import RelatedField
 from mypy.errors import Errors
 from mypy.nodes import MypyFile, TypeInfo
 from mypy.options import Options
-from mypy.plugin import (
-    AttributeContext, ClassDefContext, FunctionContext, MethodContext, Plugin,
-)
+from mypy.plugin import AnalyzeTypeContext, AttributeContext, ClassDefContext, FunctionContext, MethodContext, Plugin
 from mypy.types import Type as MypyType
 
 from mypy_django_plugin.django.context import DjangoContext
@@ -233,6 +231,15 @@ class NewSemanalDjangoPlugin(Plugin):
             return partial(request.set_auth_user_model_as_type_for_request_user, django_context=self.django_context)
         return None
 
+    def get_type_analyze_hook(self, fullname: str
+                              ) -> Optional[Callable[[AnalyzeTypeContext], MypyType]]:
+        info = self._get_typeinfo_or_none(fullname)
+        if (info
+                and info.has_base(fullnames.QUERYSET_CLASS_FULLNAME)
+                and not info.has_base(fullnames.BASE_MANAGER_CLASS_FULLNAME)):
+            return partial(querysets.set_first_generic_param_as_default_for_second, fullname=fullname)
+        return None
+
 
 def plugin(version):
     return NewSemanalDjangoPlugin

mypy_django_plugin/transformers/querysets.py

@@ -1,10 +1,11 @@
 from collections import OrderedDict
-from typing import List, Optional, Sequence, Type, Union
+from typing import List, Optional, Sequence, Type, Union, cast
 
 from django.core.exceptions import FieldError
 from django.db.models.base import Model
-from mypy.nodes import Expression, NameExpr
-from mypy.plugin import FunctionContext, MethodContext
+from mypy.newsemanal.typeanal import TypeAnalyser
+from mypy.nodes import Expression, NameExpr, TypeInfo
+from mypy.plugin import FunctionContext, MethodContext, AnalyzeTypeContext
 from mypy.types import AnyType, Instance, Type as MypyType, TypeOfAny
 
 from mypy_django_plugin.django.context import DjangoContext
@@ -169,3 +170,20 @@ def extract_proper_type_queryset_values(ctx: MethodContext, django_context: Djan
 
     row_type = helpers.make_typeddict(ctx.api, column_types, set(column_types.keys()))
     return helpers.reparametrize_instance(ctx.default_return_type, [model_type, row_type])
+
+
+def set_first_generic_param_as_default_for_second(ctx: AnalyzeTypeContext, fullname: str) -> MypyType:
+    type_analyser_api = cast(TypeAnalyser, ctx.api)
+
+    info = helpers.lookup_fully_qualified_typeinfo(type_analyser_api.api, fullname)  # type: ignore
+    assert isinstance(info, TypeInfo)
+
+    if not ctx.type.args:
+        return Instance(info, [AnyType(TypeOfAny.explicit), AnyType(TypeOfAny.explicit)])
+
+    args = ctx.type.args
+    if len(args) == 1:
+        args = [args[0], args[0]]
+
+    analyzed_args = [type_analyser_api.analyze_type(arg) for arg in args]
+    return Instance(info, analyzed_args)

mypy_django_plugin/transformers/settings.py

@@ -1,11 +1,6 @@
-from typing import cast
-
-from mypy.checker import TypeChecker
 from mypy.nodes import MemberExpr, TypeInfo
 from mypy.plugin import AttributeContext, FunctionContext
-from mypy.types import Instance
-from mypy.types import Type as MypyType
-from mypy.types import TypeType
+from mypy.types import Instance, Type as MypyType, TypeType
 
 from mypy_django_plugin.django.context import DjangoContext
 from mypy_django_plugin.lib import helpers

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

@@ -29,3 +29,10 @@
 
                 class Blog(models.Model):
                     created_at = models.DateTimeField()
+
+-   case: queryset_could_be_specified_with_one_type
+    main: |
+        from typing import Optional
+        from django.db import models
+        queryset: models.QuerySet[models.Model] = models.QuerySet()
+        reveal_type(queryset)  # N: Revealed type is 'django.db.models.query.QuerySet[django.db.models.base.Model, django.db.models.base.Model]'