Add docs for --local-partial-types option #8201
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JukkaL
reviewed
Jan 9, 2020
JukkaL
reviewed
Jan 13, 2020
docs/source/command_line.rst
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| @@ -482,6 +482,32 @@ of the above sections. | |||
| # 'items' now has type List[List[str]] | |||
| ... | |||
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| .. option:: --local-partial-types | |||
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| By default, mypy won't check partial types spanning module top level or class top level. | |||
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This sentence is pretty vague. It would be better to also introduce the concept "partial types" before discussing it.
This is an important case where this option makes a difference:
class A:
x = None # Need type annotation here if using --local-partial-types
def __init__(self) -> None:
self.x = 1
reveal_type(A().x) # Union[int, None] without --local-partial-typesThis example also makes it easier to see why this is called "local partial types" -- it disallows inferring variable type from two assignments in different scopes (for example, in class body and inside a method).
docs/source/command_line.rst
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| l2 = [] # type: List[int] | ||
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| class Foo: | ||
| bar = None # error |
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Similar to above -- --local-partial-types causes this to be an error.
JukkaL
approved these changes
Jan 17, 2020
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Thanks for the review! |
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resolves #8046, document the
--local-partial-typescommand line option