reportInvalidCast for cast(None, object()): "convert the expression to object first"

[jorenham]

https://basedpyright.com/?code=JYWwDg9gTgLgBDAnmYA7A5nAhgZwQKBgDoBjXGACgDkJUBTAGjggCMArOkygSm6A

So a couple of months ago I tried to do

import typing as t
t.cast(None, object())

which gave

Conversion of type `object` to type `None` may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to `object` first.  (reportInvalidCast)

So I decided to follow the advice, i.e.:

convert the expression to object first.

... but after I did that, it said it again. So it was obvious to me that I should keep at it for a while.

Then after I had cast object to object for the 3000th time, my brain raised a RecursionError!
So now I'm wondering if maybe there's a chance that there's a bug involved here, or if I should brain.setrecursionlimit(1 << 20) and give it another shot 🤔.
Any thoughts?

[DetachHead]

must be some annoying special casing with None causing this. thanks for reporting

[jorenham]

It's not a problem to e.g. cast(Never, object()) or cast(Any, object()).

But this issue also appears to be the case for cast(type[T], object()) with T e.g. Any, object, or int. The only except I managed to find was cast(type[Never], object()), which is allowed.

[jorenham]

I also found a workaround:

cast(None, cast(Never, object()))