(🐞) No error when assigning non-concrete type object to variable of `type` bound with a union (`Protocol`, `abstract`)
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bug
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
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Description
from typing import Protocol, Callable
from abc import ABC, abstractmethod
class A(ABC):
@abstractmethod
def f(self) -> None: ...
class P(Protocol):
a: int
ta1: type[A] = A # error
ta2: type[A | P] = A # no error
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First steps
- Read the whole issue, then the project's contributing guide.
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- Open a pull request that references the issue number.
Research direction
Run the linked mypy-play reproduction with the shown Python code and strict flags, then trace the type-checking path for assignments to a type bound by a union containing a Protocol or abstract class. Done means the second assignment receives the same appropriate diagnostic as the first, with tests covering the reported case.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 35/100