Invalid type for redefined variable inside nested function
Open
Nobody has claimed this yet.
bug
false-positive
priority-0-high
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
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Description
The revealed type in this example is int, even though it should be str:
# mypy: allow-redefinition
def f() -> None:
x = 0
print(x)
x = 'x'
def g() -> None:
reveal_type(x) # int, but should be str
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 mypy example and confirming that reveal_type(x) reports int instead of str. Trace the handling of allow-redefinition across the nested function boundary; done means the revealed type in g is str while the example remains valid.
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
- Mostly clear
- Newbie friendliness
- 45/100