#11719: Cannot use higher-rank kinds with type families -------------------------------------+------------------------------------- Reporter: ocharles | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler (Type | Version: 8.0.1-rc2 checker) | Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: GHC rejects | Test Case: valid program | dependent/should_compile/T11719 Blocked By: | Blocking: Related Tickets: #13913 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): Something to consider (I don't know if I got the typing right, but allowing higher rank kinds in splitting type application) {{{#!hs type RudeWord a = forall xx. xx -> a type family Split (a :: res) :: forall arg. Maybe (RudeWord res, arg) where Split ((f :: RudeWord res) (a :: k)) = 'Just '(f, a) Split _ = 'Nothing }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11719#comment:21 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler