[Haskell] Re: Using implicit parameter constraints in data decl

[Simon Peyton-Jones]

| (While experimenting with this, I discovered to my surprise that GHCi
| accepts the type "IO ((Num a) => a)", and describes it as "forall a.
IO
| ({Num a} => a)". However it rejects "return 12 :: IO ((Num a) => a)",
| saying that it can't deduce (Num ({Num a} => a)). Is this a bug?)

Yes, it's a bug.  I'm fixing it as we speak. Thanks for pointing it out.

Simon