[Haskell-cafe] Confused about type seen in the wild
dagitj at gmail.com
Thu Apr 10 17:12:14 UTC 2014
On Thu, Apr 10, 2014 at 9:27 AM, Albert Y. C. Lai <trebla at vex.net> wrote:
Yes, GHC accepts "X => Y => Z" and makes it "(X, Y) => Z". In fact, go
> whee :: Show a => Eq a => a => Bool
> whee x = x == x && null (show x)
> It is valid and it means (Show a, Eq a) => a -> Bool. Try it!
What extensions do you have turned on? I'm trying this is ghci (7.6.3) and
I can't get it to work even with DataKinds and ConstraintKinds.
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