(🐞) `Protocol`s that narrow to modules become `Any`
Open
Nobody has claimed this yet.
bug
topic-type-narrowing
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
- PR metrics pending
Description
from typing import Protocol
import test2 # def foo() -> None: ...
class P(Protocol):
def foo(self) -> None: ...
a: P = test2
reveal_type(a.foo()) # None
a = test2
reveal_type(a.foo()) # Any
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by running the provided Protocol example with the test2 module and compare the two reveal_type results. Trace the type-checking path for assigning a module to P, and consider the issue resolved when both assignments preserve the protocol method type so a.foo() is revealed as None rather than Any.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100