`mypy` fails to correctly understand some iterable type in `*args`
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bug
- Dominant language
- Python
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Description
class MyList(list[int]): ...
def test(x: MyList, y: list[int]) -> None:
reveal_type( [*x] ) # list[Any] ❌
reveal_type( [*y] ) # list[int] ✅
[*x] should infer as list[int].
https://mypy-play.net/?mypy=latest&python=3.12&gist=5ed11116bf41c5aa803adc3f9333a125
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Research direction
Start with the linked mypy playground and reproduce the reveal_type([*x]) result for the MyList example. Trace iterable unpacking type inference and add a regression test in the relevant mypy test area; done means the expression is revealed as list[int] without regressing the existing list[int] case.
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
- 48/100