coverage checker iteration flag isn't documented outside of release notes!
as per #11195 (closed)##11996 (closed) and the ghc 8.0rc release notes,
-fmax-pmcheck-iterations is now a flag! its not listed as a documented flag, aside from mention in the release notes (though a search for pattern or matching will have a hard time turning it up)
is this deliberate or not? (nb: not that i've used it, but making note of that subtlety)