Update type annotation for create_model function

changes/2071-uriyyo.md

@@ -0,0 +1 @@
+Updated `create_model` return type annotation to return type which inherits from `__base__` argument.

pydantic/main.py

@@ -870,11 +870,11 @@ def create_model(
     __model_name: str,
     *,
     __config__: Type[BaseConfig] = None,
-    __base__: Type[BaseModel] = None,
+    __base__: Type['Model'] = None,
     __module__: str = __name__,
     __validators__: Dict[str, classmethod] = None,
     **field_definitions: Any,
-) -> Type[BaseModel]:
+) -> Type['Model']:
     """
     Dynamically create a model.
     :param __model_name: name of the created model
@@ -887,11 +887,12 @@ def create_model(
         `foobar=(str, ...)` or `foobar=123`, or, for complex use-cases, in the format
         `<name>=<FieldInfo>`, e.g. `foo=Field(default_factory=datetime.utcnow, alias='bar')`
     """
-    if __base__:
+
+    if __base__ is not None:
         if __config__ is not None:
             raise ConfigError('to avoid confusion __config__ and __base__ cannot be used together')
     else:
-        __base__ = BaseModel
+        __base__ = cast(Type['Model'], BaseModel)
 
     fields = {}
     annotations = {}

tests/mypy/modules/plugin_success.py

@@ -1,6 +1,6 @@
 from typing import ClassVar, Optional, Union
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, create_model
 from pydantic.dataclasses import dataclass
 
 
@@ -133,3 +133,9 @@ class Model(BaseModel):
 
 
 _ = NestedModel.Model
+
+
+DynamicModel = create_model('DynamicModel', __base__=Model)
+
+dynamic_model = DynamicModel(x=1, y='y')
+dynamic_model.x = 2