6 Feb
2016
6 Feb
'16
7:33 a.m.
On Sat, Feb 06, 2016 at 01:31:14PM +0100, Marcin Mrotek wrote:
maybe :: forall (r :: RuntimeRep) (a :: *) (b :: TYPE r). b -> (a -> b) -> Maybe a -> b
`b` also is a type of an argument in that function, so I think being levity polymorphic on it in is excluded by "GC going haywire chasing values as if they were pointers" as described here: https://mail.haskell.org/pipermail/ghc-devs/2016-February/011269.html
Ah, "The levity polymorphic type never appears directly to the left of an arrow.". Thanks.