Allow comparisons to refine Optional types without strict-optional #4523
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(Let's hold off on this a bit, we've discovered some problems with it in our own codebase.) |
Please let me know when the problems are solved, so that I can proceed with a review. |
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IIUC that's in @msullivan's court. |
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Before this can land, we need to fix #3526, since this change exposes a bunch of instances of it. |
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The bad news is that I went and fixed #3526 and it turns out that wasn't actually what was causing trouble internally. |
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@ilevkivskyi this is ready for review now |
mypy/binder.py
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| @@ -271,11 +271,10 @@ def assign_type(self, expr: Expression, | |||
| and not restrict_any): | |||
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This doesn't need to be on a separate line.
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This causes a small handful of errors in internal codebases that will be easy to fix. A couple were weird second-order effects in which doing the refinement meant that a type was no longer a Union and so behaved differently when computing types in a ternary expression. Sigh. |
Fixes #4520.