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Better type for self in untyped functions #4637
Description
Running mypy --check-untyped-defs against the code below will give an error only for method m2():
/tmp/foo.py:6: error: "Dict[str, str]" has no attribute "unknown_method"
When in fact I'd expect a similar error for the self.unknown_method() line.
class Foo:
def m(self):
self.unknown_method()
def m2(self):
d = dict(foo='bar')
d.unknown_method()
However, if I add a type annotation to method m(): def m(self) -> None:, I do get the error I expected:
/tmp/foo.py:3: error: "Foo" has no attribute "unknown_method"
/tmp/foo.py:6: error: "Dict[str, str]" has no attribute "unknown_method"
Activity
JukkaL commentedon Feb 26, 2018
The type of
selfisAnyif you don't have an annotation -- all unannotated arguments are givenAnytypes. However, maybeselfshould be an exception and work similarly to annotated functions. Theclsargument of class methods is also currentlyAnyin unannotated methods even when using--check-unyped-defs.gsalgado commentedon Feb 26, 2018
Hmm, yeah, I think that'd make sense, in the same way that
selfgets assigned the correct type (Foo) when the method has just a return type annotation (def m(self) -> None:)gvanrossum commentedon Feb 26, 2018
[-]Method body not checked even with --check-untyped-defs[/-][+]Better type for self in untyped functions[/+]Give self argument the correct type when using check_untyped_defs (#7530