#393: functions without implementations -------------------------------------+------------------------------------- Reporter: c_maeder | Owner: Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Compiler (Type | Version: None checker) | Resolution: | Keywords: newcomer 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): Should also work for methods. This currently fails: {{{#!hs class FFunctor p where ffmap :: (forall x. f x -> g x) -> (p f -> p g) instance FFunctor (TList l) where ffmap :: (forall x. f x -> g x) -> (TList l f -> TList l g) ffmap = undefined }}} I would like {{{#!hs class FFunctor p where ffmap :: (forall x. f x -> g x) -> (p f -> p g) instance FFunctor (TList l) where ffmap :: (forall x. f x -> g x) -> (TList l f -> TList l g) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/393#comment:33 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler