[project @ 2000-06-09 15:53:12 by simonpj]
GHC gets upset if you have types like Eq a => a->a where 'a' is *not* universally quantified. By "upset" I mean that the typechecker generates rather bogus code, that subsequently kills Lint. Such types used to be rejected in the renamer, but Jeff removed that in favour of an ambiguity check in TcMonoType. I remember agreeing to move the renamer check to the type checker, and Jeff did this, but the check in TcMonoType was only checking for *ambiguity*, which isn't quite the same. I've restored the missing check and commented it better in TcMonoType. Jeff: if this isn't right for you, let's dicuss. Incidentally, I also generalise the ambiguity check to detect forall a. ?x::a => Int which is ambiguous. I did a few formatting changes too.