"Statement is unreachable" false positive when calling `callable` on union with `object`
Open
Nobody has claimed this yet.
bug
topic-reachability
topic-type-narrowing
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
- PR metrics pending
Description
def foo(value: object | str) -> None:
if callable(value):
print(1) # Statement is unreachable [unreachable]
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 reproducing the linked mypy-play example, then trace callable-based type narrowing and unreachable diagnostics in mypy. Done means the example no longer reports print(1) as unreachable, with regression coverage for the reproduced case.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- compilers, devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 38/100