property fail on fget, fset

Please provide more information to help us understand the issue:

• Are you reporting a bug, or opening a feature request?
  Bug
• Please insert below the code you are checking with mypy,
  or a mock-up repro if the source is private. We would appreciate
  if you try to simplify your case to a minimal repro.

class A():
    @property
    def a(self) -> float:
        return 0.5

class B():
    @property
    def a(self) -> float:
        return 1.5

class C(A, B):
    is_a:bool = True
    @property
    def a(self) -> float:
        if self.is_a:
            return A.a.fget(self)
        else:
            return B.a.fget(self)


if __name__ == '__main__':
    c = C()
    assert c.a ==0.5
    c.is_a = False
    assert c.a == 1.5

• What is the actual behavior/output?

warning: Returning Any from function declared to return "float"
error: "Callable[[A], float]" has no attribute "fget"
warning: Returning Any from function declared to return "float"
error: "Callable[[B], float]" has no attribute "fget"

• What is the behavior/output you expect?
  mypy should pass

• What are the versions of mypy and Python you are using?
  mypy 0.650
Python 3.6.5

  Do you see the same issue after installing mypy from Git master?
  Yes

• What are the mypy flags you are using? (For example --strict-optional)
  no flags.

• If mypy crashed with a traceback, please paste
  the full traceback below.

(You can freely edit this text, please remove all the lines
you believe are unnecessary.)

Comienza ejecutando mypy en la reproducción mínima del issue y compara cómo trata el acceso a propiedades mediante A.a.fget y B.a.fget. Traza el recorrido de comprobación de tipos para los descriptores de propiedades y los atributos invocables; se considera terminado cuando el ejemplo pasa con los tipos de retorno float esperados.