Now type(None) is more consistent, refs #11550
#11552
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sobolevn
commented
Nov 14, 2021
| @@ -2686,6 +2686,8 @@ def check_and_set_up_type_alias(self, s: AssignmentStmt) -> bool: | |||
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| res: Optional[Type] = None | |||
| if self.is_none_alias(rvalue): | |||
| # This is really `Type[None]`, not just `None`, but we use | |||
| # this as a backwards compatible solution. See #11550 | |||
| res = NoneType() | |||
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This can still cause issues, for example:
none = type(None)
print(none()) # E: error: Cannot instantiate type "Type[None]"But, I've decided to keep this as-is (and do not change this to res = TypeType(NoneType())), because I'm affraid this can cause issues to our old users, who use type(None) for annotations.
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If we decide to change this, we can try to make Type[None] and None compatible. So, this will work:
n = type(None)
var: n = None # will still be ok!
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I think types that are none should be annotated None. If someone tries to annotate something that is none as type(None) we should give an error and tell them to annotate it as : None (though I also expect this to be rather rare).
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Related #11551 |
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Closes #11550
This might fail in some unexpected cases.