Classes with __call__ defined should be a subtype of Callable

def apply(f: Callable[[int], int], x: int) -> int:
  return f(x)

class Add5(object):
  def __call__(self, x: int) -> int:
    return x + 5

apply(Add5(), 5)

This code snippet doesn't type check because Mypy doesn't treat Add5() as a Callable[[int], int]

Moved to 0.5 since this comes up pretty frequently.

I'm going to start looking into this one.

@rwbarton

WIP at https://github.com/margaret/mypy/tree/user_defined_callable (thanks @rwbarton for helping)
Currently debugging broken tests, specifically

class A(type):
    def __init__(self) -> None: pass
def f(x: type): pass
f(A())

Does not work and returns
error: Argument 1 to "f" has incompatible type Callable[[Any, Any], Any]; expected "type"

Have you tried putting a pdb.set_trace() call in errors.Errors.report()
and tracing back to the cause of this message?

I believe type is special in some ways, maybe that's biting you?

On Fri, Jun 3, 2016 at 7:33 PM, Margaret Sy [email protected]
wrote:

WIP at https://github.com/margaret/mypy/tree/user_defined_callable
Currently debugging broken tests, specifically

class A(type):
def init(self) -> None: pass
def f(x: type): pass
f(A())

Does not work and returns
error: Argument 1 to "f" has incompatible type Callable[[Any, Any], Any];
expected "type"

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Moving to an earlier milestone since the partial issue is kind of important.

A related issue is the join of Callable and an instance type that defines __call__ (see #2779).

@ilevkivskyi

@ilevkivskyi Are you still working on this? If not it's better to un-assign.

Protocols #3132 will fix this, no additional work here will be needed when they are merged.

requests: explicitly support AuthBase for Session.auth

This is now fixed by #3132

requests: add more accurate stubs for certain fields of the Session o…

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Classes with call defined should be a subtype of Callable #797

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Classes with __call__ defined should be a subtype of Callable #797

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JukkaL commented on May 5, 2016

margaret commented on Jun 3, 2016

margaret commented on Jun 4, 2016

gvanrossum commented on Jun 4, 2016

gvanrossum commented on Nov 28, 2016

JukkaL commented on Jan 31, 2017

gvanrossum commented on May 5, 2017

ilevkivskyi commented on May 5, 2017

ilevkivskyi commented on Aug 19, 2017

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Classes with call defined should be a subtype of Callable #797