add Model.__init__ typechecking

django-stubs/contrib/admin/models.pyi

@@ -1,20 +1,17 @@
-import datetime
-from typing import Any, Dict, List, Optional, Union
+from typing import Any, Optional, Union
 from uuid import UUID
 
-from django.db import models
+from django.contrib.contenttypes.models import ContentType
 from django.db.models.base import Model
 
+from django.db import models
+
 ADDITION: int
 CHANGE: int
 DELETION: int
 ACTION_FLAG_CHOICES: Any
 
 class LogEntryManager(models.Manager):
-    creation_counter: int
-    model: None
-    name: None
-    use_in_migrations: bool = ...
     def log_action(
         self,
         user_id: int,
@@ -22,23 +19,18 @@ class LogEntryManager(models.Manager):
         object_id: Union[int, str, UUID],
         object_repr: str,
         action_flag: int,
-        change_message: Union[
-            Dict[str, Dict[str, List[str]]], List[Dict[str, Dict[str, Union[List[str], str]]]], str
-        ] = ...,
+        change_message: Any = ...,
     ) -> LogEntry: ...
 
 class LogEntry(models.Model):
-    content_type_id: int
-    id: None
-    user_id: int
-    action_time: datetime.datetime = ...
-    user: Any = ...
-    content_type: Any = ...
-    object_id: str = ...
-    object_repr: str = ...
-    action_flag: int = ...
-    change_message: str = ...
-    objects: Any = ...
+    action_time: models.DateTimeField = ...
+    user: models.ForeignKey = ...
+    content_type: models.ForeignKey[ContentType] = ...
+    object_id: models.TextField = ...
+    object_repr: models.CharField = ...
+    action_flag: models.PositiveSmallIntegerField = ...
+    change_message: models.TextField = ...
+    objects: LogEntryManager = ...
     def is_addition(self) -> bool: ...
     def is_change(self) -> bool: ...
     def is_deletion(self) -> bool: ...

django-stubs/contrib/auth/models.pyi

@@ -1,46 +1,33 @@
-import datetime
 from typing import Any, List, Optional, Set, Tuple, Type, Union
 
 from django.contrib.auth.base_user import AbstractBaseUser as AbstractBaseUser, BaseUserManager as BaseUserManager
+from django.contrib.contenttypes.models import ContentType
 from django.db.models.manager import EmptyManager
 
+from django.contrib.auth.validators import UnicodeUsernameValidator
 from django.db import models
 
 def update_last_login(sender: Type[AbstractBaseUser], user: AbstractBaseUser, **kwargs: Any) -> None: ...
 
 class PermissionManager(models.Manager):
-    creation_counter: int
-    model: None
-    name: None
-    use_in_migrations: bool = ...
     def get_by_natural_key(self, codename: str, app_label: str, model: str) -> Permission: ...
 
 class Permission(models.Model):
     content_type_id: int
-    id: int
-    name: str = ...
-    content_type: Any = ...
+    name: models.CharField = ...
+    content_type: models.ForeignKey[ContentType] = ...
     codename: str = ...
     def natural_key(self) -> Tuple[str, str, str]: ...
 
 class GroupManager(models.Manager):
-    creation_counter: int
-    model: None
-    name: None
-    use_in_migrations: bool = ...
     def get_by_natural_key(self, name: str) -> Group: ...
 
 class Group(models.Model):
-    id: None
-    name: str = ...
-    permissions: Any = ...
+    name: models.CharField = ...
+    permissions: models.ManyToManyField[Permission] = ...
     def natural_key(self): ...
 
 class UserManager(BaseUserManager):
-    creation_counter: int
-    model: None
-    name: None
-    use_in_migrations: bool = ...
     def create_user(
         self, username: str, email: Optional[str] = ..., password: Optional[str] = ..., **extra_fields: Any
     ) -> AbstractUser: ...
@@ -49,9 +36,9 @@ class UserManager(BaseUserManager):
     ) -> AbstractBaseUser: ...
 
 class PermissionsMixin(models.Model):
-    is_superuser: Any = ...
-    groups: Any = ...
-    user_permissions: Any = ...
+    is_superuser: models.BooleanField = ...
+    groups: models.ManyToManyField[Group] = ...
+    user_permissions: models.ManyToManyField[Permission] = ...
     def get_group_permissions(self, obj: None = ...) -> Set[str]: ...
     def get_all_permissions(self, obj: Optional[str] = ...) -> Set[str]: ...
     def has_perm(self, perm: Union[Tuple[str, Any], str], obj: Optional[str] = ...) -> bool: ...
@@ -59,14 +46,13 @@ class PermissionsMixin(models.Model):
     def has_module_perms(self, app_label: str) -> bool: ...
 
 class AbstractUser(AbstractBaseUser, PermissionsMixin):  # type: ignore
-    is_superuser: bool
-    username_validator: Any = ...
-    username: str = ...
-    first_name: str = ...
-    last_name: str = ...
-    email: str = ...
-    is_staff: bool = ...
-    date_joined: datetime.datetime = ...
+    username_validator: UnicodeUsernameValidator = ...
+    username: models.CharField = ...
+    first_name: models.CharField = ...
+    last_name: models.CharField = ...
+    email: models.EmailField = ...
+    is_staff: models.BooleanField = ...
+    date_joined: models.DateTimeField = ...
     EMAIL_FIELD: str = ...
     USERNAME_FIELD: str = ...
     def clean(self) -> None: ...

django-stubs/contrib/postgres/fields/__init__.pyi

@@ -8,3 +8,4 @@ from .ranges import (
     DateRangeField as DateRangeField,
     DateTimeRangeField as DateTimeRangeField,
 )
+from .hstore import HStoreField as HStoreField

django-stubs/contrib/postgres/fields/array.pyi

@@ -13,14 +13,8 @@ class ArrayField(CheckFieldDefaultMixin, Field, Generic[_T]):
     default_validators: Any = ...
     from_db_value: Any = ...
     def __init__(self, base_field: _T, size: Optional[int] = ..., **kwargs: Any) -> None: ...
-    def check(self, **kwargs: Any) -> List[Any]: ...
     @property
     def description(self): ...
-    def get_db_prep_value(self, value: Any, connection: Any, prepared: bool = ...): ...
-    def to_python(self, value: Any): ...
-    def value_to_string(self, obj: Any): ...
     def get_transform(self, name: Any): ...
-    def validate(self, value: Any, model_instance: Any) -> None: ...
-    def run_validators(self, value: Any) -> None: ...
-    def __set__(self, instance, value: Sequence[_T]): ...
+    def __set__(self, instance, value: Sequence[_T]) -> None: ...
     def __get__(self, instance, owner) -> List[_T]: ...

django-stubs/contrib/postgres/fields/hstore.pyi

@@ -0,0 +1,17 @@
+from typing import Any
+
+from django.db.models import Field, Transform
+from .mixins import CheckFieldDefaultMixin
+
+class HStoreField(CheckFieldDefaultMixin, Field):
+    def get_transform(self, name) -> Any: ...
+
+class KeyTransform(Transform):
+    def __init__(self, key_name: str, *args: Any, **kwargs: Any): ...
+
+class KeyTransformFactory:
+    def __init__(self, key_name: str): ...
+    def __call__(self, *args, **kwargs) -> KeyTransform: ...
+
+class KeysTransform(Transform): ...
+class ValuesTransform(Transform): ...

django-stubs/db/models/fields/__init__.pyi

@@ -1,6 +1,6 @@
 import uuid
 from datetime import date, time, datetime, timedelta
-from typing import Any, Optional, Tuple, Iterable, Callable, Dict, Union, Type
+from typing import Any, Optional, Tuple, Iterable, Callable, Dict, Union, Type, TypeVar
 import decimal
 
 from django.db.models import Model

django-stubs/db/models/query.pyi

@@ -95,13 +95,14 @@ class QuerySet(Iterable[_T], Sized):
     def raw(
         self, raw_query: str, params: Any = ..., translations: Optional[Dict[str, str]] = ..., using: None = ...
     ) -> RawQuerySet: ...
-    def values(self, *fields: Union[str, Combinable], **expressions: Any) -> ValuesIterable: ...
-    @overload
-    def values_list(self, *fields: Union[str, Combinable], named: Literal[True]) -> NamedValuesListIterable: ...
-    @overload
-    def values_list(self, *fields: Union[str, Combinable], flat: Literal[True]) -> FlatValuesListIterable: ...
-    @overload
-    def values_list(self, *fields: Union[str, Combinable]) -> ValuesListIterable: ...
+    def values(self, *fields: Union[str, Combinable], **expressions: Any) -> QuerySet: ...
+    def values_list(self, *fields: Union[str, Combinable], flat: bool = ..., named: bool = ...) -> QuerySet: ...
+    # @overload
+    # def values_list(self, *fields: Union[str, Combinable], named: Literal[True]) -> NamedValuesListIterable: ...
+    # @overload
+    # def values_list(self, *fields: Union[str, Combinable], flat: Literal[True]) -> FlatValuesListIterable: ...
+    # @overload
+    # def values_list(self, *fields: Union[str, Combinable]) -> ValuesListIterable: ...
     def dates(self, field_name: str, kind: str, order: str = ...) -> QuerySet: ...
     def datetimes(self, field_name: str, kind: str, order: str = ..., tzinfo: None = ...) -> QuerySet: ...
     def none(self) -> QuerySet[_T]: ...

django-stubs/forms/widgets.pyi

@@ -1,7 +1,7 @@
 from datetime import time
 from decimal import Decimal
 from itertools import chain
-from typing import Any, Callable, Dict, Iterator, List, Optional, Set, Tuple, Type, Union, Iterable
+from typing import Any, Callable, Dict, Iterator, List, Optional, Set, Tuple, Type, Union, Iterable, Sequence
 
 from django.contrib.admin.options import BaseModelAdmin
 from django.core.files.base import File
@@ -114,6 +114,8 @@ class CheckboxInput(Input):
     check_test: Callable = ...
     def __init__(self, attrs: Optional[Dict[str, str]] = ..., check_test: Optional[Callable] = ...) -> None: ...
 
+_OptAttrs = Dict[str, Any]
+
 class ChoiceWidget(Widget):
     allow_multiple_selected: bool = ...
     input_type: Optional[str] = ...
@@ -123,17 +125,9 @@ class ChoiceWidget(Widget):
     checked_attribute: Any = ...
     option_inherits_attrs: bool = ...
     choices: List[List[Union[int, str]]] = ...
-    def __init__(
-        self,
-        attrs: Optional[Dict[str, Union[bool, str]]] = ...,
-        choices: Union[
-            Iterator[Any], List[List[Union[int, str]]], List[Tuple[Union[time, int], int]], List[int], Tuple
-        ] = ...,
-    ) -> None: ...
-    def options(self, name: str, value: List[str], attrs: Dict[str, Union[bool, str]] = ...) -> None: ...
-    def optgroups(
-        self, name: str, value: List[str], attrs: Optional[Dict[str, Union[bool, str]]] = ...
-    ) -> List[Tuple[Optional[str], List[Dict[str, Union[Dict[str, Union[bool, str]], time, int, str]]], int]]: ...
+    def __init__(self, attrs: Optional[_OptAttrs] = ..., choices: Sequence[Tuple[Any, Any]] = ...) -> None: ...
+    def options(self, name: str, value: List[str], attrs: Optional[_OptAttrs] = ...) -> None: ...
+    def optgroups(self, name: str, value: List[str], attrs: Optional[_OptAttrs] = ...) -> Any: ...
     def create_option(
         self,
         name: str,
@@ -142,8 +136,8 @@ class ChoiceWidget(Widget):
         selected: Union[Set[str], bool],
         index: int,
         subindex: Optional[int] = ...,
-        attrs: Optional[Dict[str, Union[bool, str]]] = ...,
-    ) -> Dict[str, Union[Dict[str, Union[bool, str]], Dict[str, bool], Set[str], time, int, str]]: ...
+        attrs: Optional[_OptAttrs] = ...,
+    ) -> Dict[str, Any]: ...
     def id_for_label(self, id_: str, index: str = ...) -> str: ...
 
 class Select(ChoiceWidget):
@@ -171,11 +165,7 @@ class CheckboxSelectMultiple(ChoiceWidget):
 class MultiWidget(Widget):
     template_name: str = ...
     widgets: List[Widget] = ...
-    def __init__(
-        self,
-        widgets: Union[List[Type[DateTimeBaseInput]], Tuple[Union[Type[TextInput], Input]]],
-        attrs: Optional[Dict[str, str]] = ...,
-    ) -> None: ...
+    def __init__(self, widgets: Sequence[Widget], attrs: Optional[_OptAttrs] = ...) -> None: ...
     @property
     def is_hidden(self) -> bool: ...
     def decompress(self, value: Any) -> Optional[Any]: ...
@@ -218,7 +208,7 @@ class SelectDateWidget(Widget):
     day_none_value: Any = ...
     def __init__(
         self,
-        attrs: None = ...,
+        attrs: Optional[_OptAttrs] = ...,
         years: Optional[Union[Tuple[Union[int, str]], range]] = ...,
         months: None = ...,
         empty_label: Optional[Union[Tuple[str, str], str]] = ...,

mypy_django_plugin/helpers.py

@@ -1,9 +1,13 @@
 import typing
 from typing import Dict, Optional
 
-from mypy.nodes import MypyFile, TypeInfo, ImportedName, SymbolNode
+from mypy.nodes import Expression, FuncDef, ImportedName, MypyFile, NameExpr, SymbolNode, TypeInfo, Var
+from mypy.plugin import FunctionContext
+from mypy.types import AnyType, CallableType, Instance, Type, TypeOfAny, TypeVarType
 
 MODEL_CLASS_FULLNAME = 'django.db.models.base.Model'
+FIELD_FULLNAME = 'django.db.models.fields.Field'
+GENERIC_FOREIGN_KEY_FULLNAME = 'django.contrib.contenttypes.fields.GenericForeignKey'
 FOREIGN_KEY_FULLNAME = 'django.db.models.fields.related.ForeignKey'
 ONETOONE_FIELD_FULLNAME = 'django.db.models.fields.related.OneToOneField'
 MANYTOMANY_FIELD_FULLNAME = 'django.db.models.fields.related.ManyToManyField'
@@ -78,3 +82,116 @@ def lookup_fully_qualified_generic(name: str, all_modules: Dict[str, MypyFile])
     if sym is None:
         return None
     return sym.node
+
+
+def parse_bool(expr: Expression) -> Optional[bool]:
+    if isinstance(expr, NameExpr):
+        if expr.fullname == 'builtins.True':
+            return True
+        if expr.fullname == 'builtins.False':
+            return False
+    return None
+
+
+def reparametrize_with(instance: Instance, new_typevars: typing.List[Type]):
+    return Instance(instance.type, args=new_typevars)
+
+
+def fill_typevars_with_any(instance: Instance) -> Type:
+    return reparametrize_with(instance, [AnyType(TypeOfAny.unannotated)])
+
+
+def extract_typevar_value(tp: Instance, typevar_name: str):
+    return tp.args[tp.type.type_vars.index(typevar_name)]
+
+
+def extract_field_setter_type(tp: Instance) -> Optional[Type]:
+    if tp.type.has_base(FIELD_FULLNAME):
+        set_method = tp.type.get_method('__set__')
+        if isinstance(set_method, FuncDef) and isinstance(set_method.type, CallableType):
+            if 'value' in set_method.type.arg_names:
+                set_value_type = set_method.type.arg_types[set_method.type.arg_names.index('value')]
+                if isinstance(set_value_type, Instance):
+                    typevar_values: typing.List[Type] = []
+                    for typevar_arg in set_value_type.args:
+                        if isinstance(typevar_arg, TypeVarType):
+                            typevar_values.append(extract_typevar_value(tp, typevar_arg.name))
+                        # if there are typevars, extract from
+                    set_value_type = reparametrize_with(set_value_type, typevar_values)
+                    return set_value_type
+
+        get_method = tp.type.get_method('__get__')
+        if isinstance(get_method, FuncDef) and isinstance(get_method.type, CallableType):
+            return get_method.type.ret_type
+    # GenericForeignKey
+    if tp.type.has_base(GENERIC_FOREIGN_KEY_FULLNAME):
+        return AnyType(TypeOfAny.special_form)
+    return None
+
+
+def extract_primary_key_type(model: TypeInfo) -> Optional[Type]:
+    # only primary keys defined in current class for now
+    for sym in model.names.values():
+        if isinstance(sym.node, Var) and isinstance(sym.node.type, Instance):
+            tp = sym.node.type
+            if tp.type.metadata.get('django', {}).get('defined_as_primary_key'):
+                field_type = extract_field_setter_type(tp)
+                return field_type
+    return None
+
+
+def extract_expected_types(ctx: FunctionContext, model: TypeInfo) -> Dict[str, Type]:
+    expected_types: Dict[str, Type] = {}
+    for base in model.mro:
+        for name, sym in base.names.items():
+            if isinstance(sym.node, Var) and isinstance(sym.node.type, Instance):
+                tp = sym.node.type
+                field_type = extract_field_setter_type(tp)
+                if tp.type.fullname() == FOREIGN_KEY_FULLNAME:
+                    ref_to_model = tp.args[0]
+                    if isinstance(ref_to_model, Instance) and ref_to_model.type.has_base(MODEL_CLASS_FULLNAME):
+                        primary_key_type = extract_primary_key_type(ref_to_model.type)
+                        if not primary_key_type:
+                            primary_key_type = AnyType(TypeOfAny.special_form)
+                        expected_types[name + '_id'] = primary_key_type
+                if field_type:
+                    expected_types[name] = field_type
+
+    primary_key_type = extract_primary_key_type(model)
+    if not primary_key_type:
+        # no explicit primary key, set pk to Any and add id
+        primary_key_type = AnyType(TypeOfAny.special_form)
+        expected_types['id'] = ctx.api.named_generic_type('builtins.int', [])
+
+    expected_types['pk'] = primary_key_type
+    return expected_types
+
+
+def get_argument_by_name(ctx: FunctionContext, name: str) -> Optional[Expression]:
+    """Return the expression for the specific argument.
+
+    This helper should only be used with non-star arguments.
+    """
+    if name not in ctx.callee_arg_names:
+        return None
+    idx = ctx.callee_arg_names.index(name)
+    args = ctx.args[idx]
+    if len(args) != 1:
+        # Either an error or no value passed.
+        return None
+    return args[0]
+
+
+def get_argument_type_by_name(ctx: FunctionContext, name: str) -> Optional[Type]:
+    """Return the type for the specific argument.
+
+    This helper should only be used with non-star arguments.
+    """
+    if name not in ctx.callee_arg_names:
+        return None
+    idx = ctx.callee_arg_names.index(name)
+    arg_types = ctx.arg_types[idx]
+    if len(arg_types) != 1:
+        # Either an error or no value passed.
+        return None
+    return arg_types[0]

mypy_django_plugin/main.py

@@ -8,6 +8,7 @@ from mypy.plugin import ClassDefContext, FunctionContext, MethodContext, Plugin
 from mypy.types import Instance, Type
 
 from mypy_django_plugin import helpers, monkeypatch
+from mypy_django_plugin.helpers import parse_bool
 from mypy_django_plugin.plugins.fields import determine_type_of_array_field
 from mypy_django_plugin.plugins.migrations import determine_model_cls_from_string_for_migrations
 from mypy_django_plugin.plugins.models import process_model_class
@@ -54,6 +55,40 @@ def determine_proper_manager_type(ctx: FunctionContext) -> Type:
     return ret
 
 
+def redefine_model_init(ctx: FunctionContext) -> Type:
+    assert isinstance(ctx.default_return_type, Instance)
+
+    api = cast(TypeChecker, ctx.api)
+    model: TypeInfo = ctx.default_return_type.type
+
+    expected_types = helpers.extract_expected_types(ctx, model)
+    for actual_name, actual_type in zip(ctx.arg_names[0], ctx.arg_types[0]):
+        if actual_name is None:
+            # We can't check kwargs reliably.
+            continue
+        if actual_name not in expected_types:
+            ctx.api.fail('Unexpected attribute "{}" for model "{}"'.format(actual_name,
+                                                                           model.name()),
+                         ctx.context)
+            continue
+        api.check_subtype(actual_type, expected_types[actual_name],
+                          ctx.context,
+                          'Incompatible type for "{}" of "{}"'.format(actual_name,
+                                                                      model.name()),
+                          'got', 'expected')
+    return ctx.default_return_type
+
+
+def set_primary_key_marking(ctx: FunctionContext) -> Type:
+    primary_key_arg = helpers.get_argument_by_name(ctx, 'primary_key')
+    if primary_key_arg:
+        is_primary_key = parse_bool(primary_key_arg)
+        if is_primary_key:
+            info = ctx.default_return_type.type
+            info.metadata.setdefault('django', {})['defined_as_primary_key'] = True
+    return ctx.default_return_type
+
+
 class DjangoPlugin(Plugin):
     def __init__(self, options: Options) -> None:
         super().__init__(options)
@@ -105,6 +140,13 @@ class DjangoPlugin(Plugin):
         if fullname in manager_bases:
             return determine_proper_manager_type
 
+        sym = self.lookup_fully_qualified(fullname)
+        if sym and isinstance(sym.node, TypeInfo):
+            if sym.node.has_base(helpers.FIELD_FULLNAME):
+                return set_primary_key_marking
+            if sym.node.metadata.get('django', {}).get('generated_init'):
+                return redefine_model_init
+
     def get_method_hook(self, fullname: str
                         ) -> Optional[Callable[[MethodContext], Type]]:
         if fullname in {'django.apps.registry.Apps.get_model',

mypy_django_plugin/plugins/fields.py

@@ -1,13 +1,12 @@
 from mypy.plugin import FunctionContext
 from mypy.types import Type, Instance
 
+from mypy_django_plugin import helpers
+
 
 def determine_type_of_array_field(ctx: FunctionContext) -> Type:
-    if 'base_field' not in ctx.callee_arg_names:
-        return ctx.default_return_type
-
-    base_field_arg_type = ctx.arg_types[ctx.callee_arg_names.index('base_field')][0]
-    if not isinstance(base_field_arg_type, Instance):
+    base_field_arg_type = helpers.get_argument_type_by_name(ctx, 'base_field')
+    if not base_field_arg_type or not isinstance(base_field_arg_type, Instance):
         return ctx.default_return_type
 
     get_method = base_field_arg_type.type.get_method('__get__')

mypy_django_plugin/plugins/models.py

@@ -2,11 +2,12 @@ from abc import ABCMeta, abstractmethod
 from typing import Dict, Iterator, Optional, Tuple, cast
 
 import dataclasses
-from mypy.nodes import AssignmentStmt, CallExpr, ClassDef, Context, Expression, Lvalue, MDEF, MemberExpr, MypyFile, NameExpr, \
-    StrExpr, SymbolTableNode, TypeInfo, Var
+from mypy.nodes import AssignmentStmt, CallExpr, ClassDef, Context, Expression, Lvalue, MDEF, MemberExpr, \
+    MypyFile, NameExpr, StrExpr, SymbolTableNode, TypeInfo, Var, Argument, ARG_STAR2
 from mypy.plugin import ClassDefContext
+from mypy.plugins.common import add_method
 from mypy.semanal import SemanticAnalyzerPass2
-from mypy.types import Instance
+from mypy.types import Instance, AnyType, TypeOfAny, NoneTyp
 
 from mypy_django_plugin import helpers
 
@@ -199,16 +200,27 @@ def extract_ref_to_fullname(rvalue_expr: CallExpr,
     return None
 
 
+def add_dummy_init_method(ctx: ClassDefContext) -> None:
+    any = AnyType(TypeOfAny.special_form)
+    var = Var('kwargs', any)
+    kw_arg = Argument(variable=var, type_annotation=any, initializer=None, kind=ARG_STAR2)
+    add_method(ctx, '__init__', [kw_arg], NoneTyp())
+    # mark as model class
+    ctx.cls.info.metadata.setdefault('django', {})['generated_init'] = True
+
+
 def process_model_class(ctx: ClassDefContext) -> None:
     initializers = [
         InjectAnyAsBaseForNestedMeta,
         AddDefaultObjectsManager,
         AddIdAttributeIfPrimaryKeyTrueIsNotSet,
         SetIdAttrsForRelatedFields,
-        AddRelatedManagers
+        AddRelatedManagers,
     ]
     for initializer_cls in initializers:
         initializer_cls.from_ctx(ctx).run()
 
+    add_dummy_init_method(ctx)
+
     # allow unspecified attributes for now
     ctx.cls.info.fallback_to_any = True

mypy_django_plugin/plugins/related_fields.py

@@ -1,20 +1,12 @@
-import typing
 from typing import Optional, cast
 
 from mypy.checker import TypeChecker
 from mypy.nodes import StrExpr, TypeInfo
 from mypy.plugin import FunctionContext
-from mypy.types import Type, CallableType, Instance, AnyType, TypeOfAny
+from mypy.types import CallableType, Instance, Type
 
 from mypy_django_plugin import helpers
-
-
-def reparametrize_with(instance: Instance, new_typevars: typing.List[Type]):
-    return Instance(instance.type, args=new_typevars)
-
-
-def fill_typevars_with_any(instance: Instance) -> Type:
-    return reparametrize_with(instance, [AnyType(TypeOfAny.unannotated)])
+from mypy_django_plugin.helpers import fill_typevars_with_any, reparametrize_with
 
 
 def get_valid_to_value_or_none(ctx: FunctionContext) -> Optional[Instance]:

scripts/typecheck_tests.py

@@ -29,6 +29,7 @@ IGNORED_ERRORS = {
         'Invalid value for a to= parameter',
         'already defined (possibly by an import)',
         'Cannot assign to a type',
+        re.compile(r'Cannot assign to class variable "[a-z_]+" via instance'),
         # forms <-> models plugin support
         '"Model" has no attribute',
         re.compile(r'Cannot determine type of \'(objects|stuff)\''),
@@ -73,7 +74,8 @@ IGNORED_ERRORS = {
     'admin_views': [
         'Argument 1 to "FileWrapper" has incompatible type "StringIO"; expected "IO[bytes]"',
         'Incompatible types in assignment',
-        '"object" not callable'
+        '"object" not callable',
+        'Incompatible type for "pk" of "Collector" (got "int", expected "str")'
     ],
     'aggregation': [
         'Incompatible types in assignment (expression has type "QuerySet[Any]", variable has type "List[Any]")',

test-data/typecheck/fields.test

@@ -93,4 +93,4 @@ class Abstract(models.Model):
         abstract = True
 class User(Abstract):
     id = models.AutoField(primary_key=True)
-[out]
+[out]

test-data/typecheck/model_create.test

@@ -0,0 +1,106 @@
+[CASE arguments_to_init_unexpected_attributes]
+from django.db import models
+
+class MyUser(models.Model):
+    pass
+user = MyUser(name=1, age=12)
+[out]
+main:5: error: Unexpected attribute "name" for model "MyUser"
+main:5: error: Unexpected attribute "age" for model "MyUser"
+
+[CASE arguments_to_init_from_class_incompatible_type]
+from django.db import models
+
+class MyUser(models.Model):
+    name = models.CharField(max_length=100)
+    age = models.IntegerField()
+user = MyUser(name=1, age=12)
+[out]
+main:6: error: Incompatible type for "name" of "MyUser" (got "int", expected "str")
+
+[CASE arguments_to_init_combined_from_base_classes]
+from django.db import models
+
+class BaseUser(models.Model):
+    name = models.CharField(max_length=100)
+    age = models.IntegerField()
+class ChildUser(BaseUser):
+    lastname = models.CharField(max_length=100)
+user = ChildUser(name='Max', age=12, lastname='Lastname')
+[out]
+
+[CASE fields_from_abstract_user_propagate_to_init]
+from django.contrib.auth.models import AbstractUser
+
+class MyUser(AbstractUser):
+    pass
+user = MyUser(username='maxim', password='password', first_name='Max', last_name='MaxMax')
+[out]
+
+[CASE generic_foreign_key_field_no_typechecking]
+from django.db import models
+from django.contrib.contenttypes.fields import GenericForeignKey
+
+class MyUser(models.Model):
+    content_object = GenericForeignKey()
+
+user = MyUser(content_object=1)
+[out]
+
+[CASE pk_refers_to_primary_key_and_could_be_passed_to_init]
+from django.db import models
+
+class MyUser1(models.Model):
+    mypk = models.CharField(primary_key=True)
+class MyUser2(models.Model):
+    pass
+user2 = MyUser1(pk='hello')
+user3= MyUser2(pk=1)
+[out]
+
+[CASE typechecking_of_pk]
+from django.db import models
+
+class MyUser1(models.Model):
+    mypk = models.CharField(primary_key=True)
+user = MyUser1(pk=1)  # E: Incompatible type for "pk" of "MyUser1" (got "int", expected "str")
+[out]
+
+[CASE can_set_foreign_key_by_its_primary_key]
+from django.db import models
+
+class Publisher(models.Model):
+    pass
+class PublisherWithCharPK(models.Model):
+    id = models.CharField(max_length=100, primary_key=True)
+class Book(models.Model):
+    publisher = models.ForeignKey(Publisher, on_delete=models.CASCADE)
+    publisher_with_char_pk = models.ForeignKey(PublisherWithCharPK, on_delete=models.CASCADE)
+
+Book(publisher_id=1, publisher_with_char_pk_id='hello')
+Book(publisher_id=1, publisher_with_char_pk_id=1)  # E: Incompatible type for "publisher_with_char_pk_id" of "Book" (got "int", expected "str")
+[out]
+
+[CASE setting_value_to_an_array_of_ints]
+from typing import List, Tuple
+
+from django.db import models
+from django.contrib.postgres.fields import ArrayField
+
+class MyModel(models.Model):
+    array = ArrayField(base_field=models.IntegerField())
+array_val: Tuple[int, ...] = (1,)
+MyModel(array=array_val)
+array_val2: List[int] = [1]
+MyModel(array=array_val2)
+array_val3: List[str] = ['hello']
+MyModel(array=array_val3)  # E: Incompatible type for "array" of "MyModel" (got "List[str]", expected "Sequence[int]")
+[out]
+
+[CASE if_no_explicit_primary_key_id_can_be_passed]
+from django.db import models
+
+class MyModel(models.Model):
+    pass
+MyModel(id=1)
+[out]