Document change in implicit quantification
Simon's big wildcard refactor (1e041b73) changed the way GHC does implicit quantification. I don't see documentation for this, however. (That patch doesn't touch the manual, and there are no release notes, at least.)
This report was prompted by this Haskell-Café post, where Tom Ellis asks why we need
-data PackMap a b s t = PackMap (Applicative f => (a -> f b) -> s -> f t) +data PackMap a b s t = PackMap (forall f. Applicative f => (a -> f b) -> s -> f t)
to update for 8.0.