`__match_args__` must catch non-existent attributes
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feature
topic-match-statement
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
- PR merge metrics
- PR metrics pending
Description
Simple case:
class MyClass:
a: int
__match_args__ = ('a', 'b')
I think that it should generate an error: there's no b attribute.
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
Locate mypy's handling of Python structural pattern matching and the match_args tuple, then inspect how attribute names are validated. Add a regression test using the MyClass example and confirm that referencing the missing b attribute produces the intended diagnostic.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100