add Model.__init__ typechecking

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]