>So LSP just says “predicates are contravariant”

Maybe just leave out the "just" for a pleasant journey?

Since the interesting part of Barbara's uh, guideline, as "almost" pointed out by your link, is "almost" the opposite of "almost" trivial..

Don't mind me, I'm imbecilic :)

(See your link's comments, at least those imbeciles "almost" get it)