#10524: PolyKinds doesn't interact well with DeriveFunctor -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by rwbarton): FWIW this isn't a regression, 7.8 fails with the same error and 7.6 bails out even earlier. And isn't 7.10's behavior in fact the correct one? The instance produced by 7.11 is ill-kinded: {{{ instance [safe] forall (k :: BOX) (f :: k -> *) (g :: * -> k). (Functor f, Functor g) => Functor (Compose f g) }}} `Functor`'s argument must really be of kind `* -> *`. (Though I don't know if this will cause any harm beyond confusing error messages down the line.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10524#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler