Fix crash when a star expression is used in isinstance #6659
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ilevkivskyi
reviewed
Apr 11, 2019
| @@ -3949,6 +3949,8 @@ def flatten(t: Expression) -> List[Expression]: | |||
| """Flatten a nested sequence of tuples/lists into one list of nodes.""" | |||
| if isinstance(t, TupleExpr) or isinstance(t, ListExpr): | |||
| return [b for a in t.items for b in flatten(a)] | |||
| elif isinstance(t, StarExpr): | |||
| return flatten(t.expr) | |||
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Technically this adds some non-trivial functionality. Could you please add tests that check the behavior (i.e. whether types are narrowed or nor) for situations like:
isinstance(x, *(str, int)) # This should fail IIUC
isinstance(x, (int, *(str, list))) # This should behave the same as (int, str, list)There was a problem hiding this comment.
I did not understand the difference between the second one and my proposed test.
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Basically your test only tests that mypy doesn't crash, while I want:
- check that type narrowing happens when it should, and doesn't happen when it shouldn't
- check both situations where tuple appears in place and where it is referenced by a variable
ilevkivskyi
reviewed
Apr 11, 2019
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Fixes #4986.