Support "x = property(...)" in class body

[JukkaL]

Currently it's not possible to define a property using x = property(...) in the class body.

(Originally from #220.)

[adiroiban]

I am not sure if this should be a separate issue.. I couldn't find the issue for properties outside of class body..

I am leaving this comment here, maybe it will help with testing of a future mypy implementation

def WritableNumber(name, default=None):
    """
    This is a generator of properties.

    Number configuration which can be written.

    A number is an integer or a float. It can be negative.
    """
    def getter(self):
        result = self._proxy.getString(self._section_name, name)
        if not result and default is not None:
            return default

        result = self._proxy.getFloat(self._section_name, name)
        if not result and default is not None:
            return default

        return result

    def setter(self, value):
        return self._proxy.setFloat(self._section_name, name, value)

    return property(getter, setter)

class MyConfig(object):
    """Class using the property generator. The class will initiate the `_proxy` member."""
    some_value = WritableNumber('config_name', default=1)

I see that you can define properties outside of a class body.

Python 3.8.2 (default, Apr 27 2020, 15:53:34) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> ca = property(lambda _: 1)
>>> class A:
...   a = ca
... 
>>> a = A()
>>> a.a
1 

[IgnacioJPickering]

Is there any known workaround for this?

[rmorshea]

@IgnacioJPickering see: #8440 (comment)