That was fast!

The answer to (1) would be to introduce "SelfType", see python/mypy#1212. So I guess we'll have to live with it for now.

As to (2), can you show the code you tried? I am trying something like you mentioned in python/mypy#1529 but I don't get an error:

class P(property):
    pass
class C:
    @P
    def attr(self) -> int:
        return 42
print(C().attr)

I'm also honestly not sure what good all the type variables do -- since you didn't make the property class itself generic, it looks like you just made the methods all generic functions, but since none of the type variables are used more than once per method you might as well have replaced them all with Any.

Finally, the __init__ signatures are rather long -- they probably should be broken up.

The problem with 2 is in the attr.setter syntax. My code for 2 was:

class fooprop(property):
    pass

class Foo:
    @fooprop
    def bar(self) -> int:
        print('returning bar=3')
        return 3

    @bar.setter
    def bar(self, value: int):
        print('tried to set bar={}'.format(value))

Running mypy, I get:

test.py:7: error: 'overload' decorator expected
test.py:12: error: Name 'bar' is not defined
test.py:12: error: 'overload' decorator expected

I'll make the suggested changes in a moment.

I think the fix for making getter/setter/deleter work correctly would be in mypy rather than here and it seems kind of tricky. It seems you'd have to change the check for property-ness in semanal.py, line 1559. Currently it's part of a long if-elif chain matching against those two names, that would have to become something more complicated.