Incomplete handling of PEP 585, difference between typing.Type[...] and builtins.type[...]

[erikkemperman]

Bug Report

Incomplete implementation of PEP 585. There are cases where explicit annotations of the first argument of class methods (or __new__) are handled correctly for typing.Type[...] but not for builtins.type[...]

To Reproduce

import typing

class Spam:
    def __new__(cls: typing.Type[typing.Self]) -> typing.Self:
        return super().__new__(cls)


class Eggs:
    def __new__(cls: type[typing.Self]) -> typing.Self:
        return super().__new__(cls)

Expected Behavior

I expected both Spam and Eggs classes to pass

Actual Behavior

Spam passes, Eggs fails:
error: Method cannot have explicit self annotation and Self type [misc]

Your Environment

• Mypy version used:
  mypy 1.4.0+dev.1ee465c9bd06170ea1a82765ec744e64cbd2a4be (compiled: no)
• Mypy command-line flags:
  (none)
• Mypy configuration options from mypy.ini (and other config files):
  (none)
• Python version used:
  3.11.3