question about main and subdomain

hello guys. i just built an adult site on my subdomain to start ,of course it is a blackhat site. and i leave nothing in my main site, and there are no links between the two.so the question is if my subdomain is banned, does my main damain got banned too? thank you in advance!

it's said that the subdomain cannot get the main domain banned unless the main domain links to the subdomain

I have seen it go both ways so I'm not sure there is a simple answer. Since the sub is still part of the main, I think it'll be in danger.