2012/2/20 José Pedro Magalhães
One last issue: Say I have a type like: "data T = C !Int" Currently GHC Generics can't express the strictness annotation. This means that your deepseq will unnecessarily evaluate the Int (since it will always be evaluated already). It would be nice if the strictness information could be added to the K1 type. (José, would it be hard to add this to GHC.Generics?)
I don't think so; I think the right place to put it is as a method of the Selector class, though.
But, I'm wondering, for your example, wouldn't/couldn't GHC optimize away `seq` calls to strict arguments?
Isn't it also an issue that bang patterns only guarantee WHNF, but there might be unevaluated data "further inside"? Obviously not a problem for !Int; I don't know if the logic is there to tell the difference.