mypy 1.11.0 `Could not find builtin symbol 'TypeAliasType'`

[claudiu-muresan-pfa]

/Users/claudiumuresan/opt/anaconda3/envs/waylay_query/lib/python3.11/site-packages/waylay/sdk/api/_models.py:196: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 1.11.0
Traceback (most recent call last):
  File "mypy/checkexpr.py", line 5830, in accept
  File "mypy/nodes.py", line 2714, in accept
  File "mypy/checkexpr.py", line 4730, in visit_type_alias_expr
  File "mypy/checkexpr.py", line 4749, in alias_type_in_runtime_context
  File "mypy/checkexpr.py", line 5863, in named_type
  File "mypy/checker.py", line 6924, in named_type
  File "mypy/checker.py", line 7041, in lookup_qualified
KeyError: "Could not find builtin symbol 'TypeAliasType' (If you are running a test case, use a fixture that defines this symbol)"
/Users/claudiumuresan/opt/anaconda3/envs/waylay_query/lib/python3.11/site-packages/waylay/sdk/api/_models.py:196: : note: use --pdb to drop into pdb
make: *** [typecheck] Error 1

[claudiu-muresan-pfa]

Here is _models.py:

from __future__ import annotations

import contextlib
from abc import ABC
from copy import deepcopy
from datetime import date, datetime
from decimal import Decimal
from inspect import isclass
from typing import (
    TYPE_CHECKING,
    Annotated,
    Any,
    Callable,
    Dict,
    List,
    Union,
    get_type_hints,
)

from typing_extensions import (
    Self,  # >=3.12
    TypeAliasType,  # >=3.12
)

if TYPE_CHECKING:
    from typing_extensions import TypeAlias  # >= Python 3.10

from pydantic import (
    BaseModel as PydanticBaseModel,
)
from pydantic import (
    ConfigDict,
    SerializationInfo,
    StrictStr,
    TypeAdapter,
    ValidationError,
    ValidationInfo,
    ValidatorFunctionWrapHandler,
    field_validator,
    model_serializer,
    model_validator,
)
from pydantic.functional_validators import ModelWrapValidatorHandler


class BaseModel(PydanticBaseModel, ABC):
    """Waylay base model class that adds additional methods to Pydantic's `BaseModel`.

    Includes a custom validator and serializer.
    """

    @model_serializer(mode="wrap")
    def _model_serializer(
        self, handler: Callable, info: SerializationInfo
    ) -> Dict[StrictStr, Any]:
        """Get the default serializer of the model.

        * Excludes `None` fields that were not set at model initialization.
        """
        model_dict = handler(self, info)
        return {
            k: v
            for k, v in model_dict.items()
            if v is not None or k in self.model_fields_set
        }

    @model_validator(mode="wrap")  # type: ignore[arg-type]
    def _model_validator(
        cls, value: Any, handler: ModelWrapValidatorHandler, info: ValidationInfo
    ):
        """Get the default validator of the model.

        When validation is called with a `skip_validation=True` context
        (e.g. `cls.model_validate(data, context={"skip_validation": True})`),
        the model is constructed without validation.
        Any fields with a `Model` type will be constructed
        from their dict representation recursively.
        """
        context = info.context or {}
        try:
            return handler(value)
        except ValidationError:
            context = info.context or {}
            if context.get("skip_validation", False):
                model = cls.model_construct(**value)
                if not model.model_fields_set:
                    raise

                # set missing fields to None
                model_fields_set = deepcopy(model.model_fields_set)
                model_fields_missing = [
                    field_name
                    for [field_name, field_info] in model.model_fields.items()
                    if field_name not in model_fields_set and field_info.is_required()
                ]
                for field_name in model_fields_missing:
                    with contextlib.suppress(ValueError, TypeError):
                        setattr(model, field_name, None)

                model.__pydantic_fields_set__ = model_fields_set
                # recursively validate set fields
                for field_name in model_fields_set:
                    field_value = getattr(model, field_name)
                    strict = (info.config or {}).get("strict")
                    with contextlib.suppress(BaseException):
                        cls.__pydantic_validator__.validate_assignment(
                            model,
                            field_name,
                            field_value,
                            strict=strict,
                            context=context,
                        )
                return model
            else:
                raise

    @field_validator("*", mode="wrap")
    def _field_validator(
        cls, value: Any, handler: ValidatorFunctionWrapHandler, info: ValidationInfo
    ):
        """Get the default field validator of the model.

        When validation is called with a `skip_validation=True` context,
        the field is assigned without validation.
        If the field is a `Model` type, the model will be constructed
        from its dict representation recursively.
        """
        context = info.context or {}
        try:
            return handler(value)
        except ValidationError:
            context = info.context or {}
            if context.get("skip_validation", False):
                if info.field_name:
                    field_type = get_type_hints(cls).get(info.field_name, Any)
                    try:
                        config = (
                            ConfigDict(arbitrary_types_allowed=True, strict=False)
                            if not isclass(field_type)
                            or not issubclass(field_type, PydanticBaseModel)
                            else None
                        )
                        return TypeAdapter(field_type, config=config).validate_python(
                            value, strict=False, context=context
                        )
                    except ValidationError:
                        return value
            else:
                raise

    def to_dict(self) -> Dict[str, Any]:
        """Convert the model instance to dict."""
        return self.model_dump(by_alias=True, exclude_none=True)

    def to_json(self) -> str:
        """Convert the model instance to a JSON-encoded string."""
        return self.model_dump_json(by_alias=True, exclude_unset=True)

    @classmethod
    def from_dict(cls, obj: dict) -> Self:
        """Create a model instance from a dict."""
        return cls.model_validate(obj)

    @classmethod
    def from_json(cls, json_data: str | bytes | bytearray) -> Self:
        """Create a model instance from a JSON-encoded string."""
        return cls.model_validate_json(json_data)


class _Model(BaseModel):
    """A simple model that allows all additional attributes."""

    model_config = ConfigDict(extra="allow")

    def __init__(self, /, **kwargs):
        super().__init__(**kwargs)
        for field in self.model_fields_set:  # pylint: disable=not-an-iterable
            setattr(
                self, field, _Model.__model_construct_recursive(getattr(self, field))
            )

    @classmethod
    def __model_construct_recursive(cls, obj: Any):
        if isinstance(obj, list):
            return [cls.__model_construct_recursive(inner) for inner in obj]
        elif isinstance(obj, dict):
            model = _Model(**obj)
            return model
        else:
            return obj


Primitive: TypeAlias = Union[
    str, bool, int, float, Decimal, bytes, datetime, date, object, None
]
Model: TypeAlias = TypeAliasType(  # type: ignore[misc]  #(https://github.com/python/mypy/issues/16614)
    "Model",
    Annotated[
        Union[List["Model"], "_Model", Primitive],  # type: ignore[misc]
        "A basic model that acts like a `simpleNamespace` "
        "or a collection over such models.",
    ],

and line 196 corresponds to:

Model: TypeAlias = TypeAliasType(  # type: ignore[misc]  #(https://github.com/python/mypy/issues/16614)

I'm using typing_extensions v4.12.2. I had no such issues when using mypy` v1.10.1.

[sobolevn]

This is enough to reproduce on main:

from typing_extensions import TypeAliasType

Model = TypeAliasType("Model", int)

[sobolevn]

Ok, here's the problem:

mypy/mypy/checkexpr.py

Lines 4672 to 4682 in 6aa46f0

	def visit_type_application(self, tapp: TypeApplication) -> Type:
	"""Type check a type application (expr[type, ...]).
	There are two different options here, depending on whether expr refers
	to a type alias or directly to a generic class. In the first case we need
	to use a dedicated function typeanal.instantiate_type_alias(). This
	is due to slight differences in how type arguments are applied and checked.
	"""
	if isinstance(tapp.expr, RefExpr) and isinstance(tapp.expr.node, TypeAlias):
	if tapp.expr.node.python_3_12_type_alias:
	return self.named_type("typing.TypeAliasType")

I have an idea about how to fix it.