Remove some "if type is None" style checks #7120
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This pull request is a continuation of my quest to make mypy cleanly type-check under the `--warn-unreachable` flag. It removes some unnecessary checks we're performing against Type-related variables. Specifically: 1. We had some old code that checked if `t.accept(TypeJoinVisitor(s))` would return None. I believe this check was added back in 2014: after auditing our type visitors, it no longer seems relevant today. 2. We had a few unnecessary `if some_instance.type is not None` style checks. I believe we always set the TypeInfo when constructing Instance classes these days, so this check also seems unnecessary. 3. Finally, we had a "if TypeInfo.bases does not actually contain Instances" style check around some protocol-related code. I'm not really sure why, but TypeInfo.bases is annotated to be of type `List[Instance]` so it should be fine to remove these checks as well.
JukkaL
approved these changes
Jul 2, 2019
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This pull request is a continuation of my quest to make mypy cleanly type-check under the
--warn-unreachableflag.It removes some unnecessary checks we're performing against Type-related variables. Specifically:
We had some old code that checked if
t.accept(TypeJoinVisitor(s))would return None. I believe this check was added back in 2014: after auditing our type visitors, it no longer seems relevant today.We had a few unnecessary
if some_instance.type is not Nonestyle checks. I believe we always set the TypeInfo when constructing Instance classes these days, so this check also seems unnecessary.Finally, we had a "if TypeInfo.bases does not actually contain Instances" style check around some protocol-related code -- but
TypeInfo.basesis of typeList[Instance].