Kind of GHC.Exts.FUN, using -> instead of forall->
Prelude> import GHC.Exts (FUN)
Prelude GHC.Exts> :k FUN
FUN :: forall (n :: GHC.Types.Multiplicity) -> * -> * -> *
the kind of FUN
is given with an irrelevant quantifier, it is dependent but n
is never used. Should this not be printed GHC.Types.Multiplicity -> Type -> Type -> Type
?
It even works to define it like that, but I'm not 100% that they're same
type FUN2 :: Multiplicity -> Type -> Type -> Type
type FUN2 m a b = FUN m a b