The documentation doesn't mention ``__set_name__``, but it does say that cached_property is useful for properties which are "effectively immutable".

The ``__set_name__`` error message is pretty cryptic, that seems to have something to do with this PEP:

https://www.python.org/dev/peps/pep-0487/

but why it is relevant here, I don't know. I would expect that cached_property should apply only to read-only properties.

So I think that at the very least, this needs better documentation and a better error message.