Problems passing around TypedDict and using it in Union.

[ngnpope]

Bug Report

I've encountered a collection of issues with TypedDict where things didn't work as I expected:

• Passing a TypedDict type to a function and calling it works fine at runtime, but mypy complains that Type[D] cannot be instantiated, that the value returned from f() is Any, and that Type[D] is not Type[D] 🤔

  D = TypedDict('D', {})
  def f(d: type[D]) -> D:
      return d()
  f(D)  # {}

  error: Returning Any from function declared to return "D"  [no-any-return]
  error: Cannot instantiate type "Type[D]"  [misc]
  error: Argument 1 to "f" has incompatible type "Type[D]"; expected "Type[D]"  [arg-type]
  

  The errors all go away if switching TypedDict('D', {}) for another type, e.g. dict, int, ...
• These issues also occur when putting a TypedDict in a Union:

  D = TypedDict('D', {})
  U = Union[int, D]
  def g(u: type[U]) -> U:
      return u()
  g(int)
  g(D)

  error: Cannot instantiate type "Type[D]"  [misc]
  error: Argument 1 to "g" has incompatible type "Type[D]"; expected "Union[Type[int], Type[D]]"  [arg-type]
  

  Only passing the TypedDict type causes a problem, and the same issue about not being able to instantiate.

To Reproduce

1. Save the following code as test.py

   from dataclasses import dataclass
   from typing import TypedDict, Union
   
   
   @dataclass
   class Point:
       x: float
       y: float
   
   
   class PointDict(TypedDict):
       x: float
       y: float
   
   
   PointLike = Union[Point, PointDict]
   
   
   class Car:
       def __init__(self, container: type[PointLike]) -> None:
           self._container = container
   
       def move(self, *, x: float, y: float) -> PointLike:
           return self._container(x=x, y=y)
   
   
   car0 = Car(container=Point)
   car1 = Car(container=PointDict)
   print(car0.move(x=1, y=2))  # Point(x=1, y=2)
   print(car1.move(x=1, y=2))  # {'x': 1, 'y': 2}
   
   
   class Boat:
       def __init__(self, not_dict: bool) -> None:
           self._container = Point if not_dict else PointDict
   
       def move(self, *, x: float, y: float) -> PointLike:
           return self._container(x=x, y=y)
   
   
   boat0 = Boat(not_dict=True)
   boat1 = Boat(not_dict=False)
   print(boat0.move(x=1, y=2))  # Point(x=1, y=2)
   print(boat1.move(x=1, y=2))  # {'x': 1, 'y': 2}
   
   
   class Truck:
       _container: type[PointLike]
   
       def __init__(self, not_dict: bool) -> None:
           self._container = Point if not_dict else PointDict
   
       def move(self, *, x: float, y: float) -> PointLike:
           return self._container(x=x, y=y)
   
   
   truck0 = Truck(not_dict=True)
   truck1 = Truck(not_dict=False)
   print(truck0.move(x=1, y=2))  # Point(x=1, y=2)
   print(truck1.move(x=1, y=2))  # {'x': 1, 'y': 2}

2. Run mypy --show-error-codes --warn-return-any test.py

Expected Behavior

No errors should be raised.

Actual Behavior

test.py:24: error: Cannot instantiate type "Type[PointDict]"  [misc]
test.py:28: error: Argument "container" to "Car" has incompatible type "Type[PointDict]"; expected "Union[Type[Point], Type[PointDict]]"  [arg-type]
test.py:38: error: Returning Any from function declared to return "Union[Point, PointDict]"  [no-any-return]
test.py:51: error: Incompatible types in assignment (expression has type "Union[Type[Point], Type[PointDict]]", variable has type "Union[Type[Point], Type[PointDict]]")  [assignment]
test.py:54: error: Cannot instantiate type "Type[PointDict]"  [misc]
Found 5 errors in 1 file (checked 1 source file)

If I replace the TypedDict (PointDict) with a typing.NamedTuple (PointTuple), then these errors all disappear.
I do get a slightly different error:

test.py:38: error: Incompatible return value type (got "object", expected "Union[Point, PointTuple]")  [return-value]
Found 1 error in 1 file (checked 1 source file)

But that is probably a different bug and can be handled by explicitly typing _container on the class as done for Truck.

Your Environment

• Mypy version used: 0.910
• Mypy command-line flags: --show-error-codes --warn-return-any
• Mypy configuration options from mypy.ini (and other config files): N/A
• Python version used: 3.9.7
• Operating system and version: Arch Linux / 5.14.16

[ngnpope]

(Was doing a drive-by review of some of my open issues and there has been some improvement here...)

Actual Behavior

test.py:24: error: Cannot instantiate type "Type[PointDict]"  [misc]
test.py:38: error: Returning Any from function declared to return "Point | PointDict"  [no-any-return]
test.py:54: error: Cannot instantiate type "Type[PointDict]"  [misc]
Found 3 errors in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.7.1
• Mypy command-line flags: --strict
• Mypy configuration options from mypy.ini (and other config files): N/A
• Python version used: 3.11.5
• Operating system and version: Arch Linux / 6.5.9