Skip to content

type[TypeVar] not checked properly with upper bound #14755

Closed

Description

@sterliakov

Bug Report

When checking a function with argument of type[SomeTypeVar], class attributes are considered missing.

To Reproduce

from typing import ClassVar, Type, TypeVar, cast

class One:
    PATTERN: ClassVar[str] = r"^([a-z]{3})$"

class Two:
    PATTERN: ClassVar[str] = r"^([0-9]{3})$"

_T = TypeVar("_T", bound=One | Two)

def foo(result_type: Type[_T]) -> _T:
    result_type.PATTERN  # E: "Type[_T]" has no attribute "PATTERN"  [attr-defined]
    return cast(_T, result_type())

foo(One)
foo(Two)

This doesn't depend on ClassVar and works with Final or plain str as well.

Gist: https://mypy-play.net/?mypy=master&python=3.10&gist=2d769a9767898e71431e59df1c2f8488

Expected Behavior

No errors (let's ignore cast for now, it's another unrelated issue).

Actual Behavior

main.py:12: error: "Type[_T]" has no attribute "PATTERN"  [attr-defined]
Found 1 error in 1 file (checked 1 source file)

Your Environment

  • Mypy version used: 1.0.0 and master
  • Mypy command-line flags: not related
  • Mypy configuration options from mypy.ini (and other config files): not related
  • Python version used: 3.9-3.11, not related

Discovered in this SO question

Activity

  1. added a commit that references this issue on Mar 15, 2023
    9cb4872
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions