#12708: RFC: Representation polymorphic Num -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): With the upcoming `UnboxedSums` {{{#!hs instance (Eq a, Eq b) => Eq (# a | b #) where (==) :: (# a | b #) -> (# a | b #) -> Bool (# a | #) == (# a' | #) = a == a' (# | b #) == (# | b' #) = b == b' _ == _ = False }}} In GHCi, version 8.1.20160930 it seems like you cannot partially apply unboxed sums `(# | #)` so I can't write {{{#!hs instance Functor ((# | #) a) instance Applicative ((# | #) a) instance Foldable ((# | #) a) ... }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12708#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler