> I feel like I'm being a pain in the ass

Nah, not at all. I'm sorry if I sounded annoyed or anything like that — that's the internet's poor ability to convey tone.

That latest test is interesting. I didn't know about that behavior, and I don't think it's documented anywhere.

> If this behavior were to ever change, we would need to know, and -rac_signalForSelector: would need to start explicitly looking up signatures on protocols to actively avoid incompatibility.

I don't think so. The documentation explicitly says that unimplemented methods will have a specific type signature. It's up to the user to ensure that the desired protocol method would match that, or use `-rac_signalForSelector:fromProtocol:` instead.