#15347: QuantifiedConstraints: Implication constraints with type families don't work -------------------------------------+------------------------------------- Reporter: aaronvargo | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.5 checker) | Keywords: Resolution: | QuantifiedConstraints Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
In order to float this type family out, we need to add a new parameter to the class,
Really? What wrong with this? {{{ class (ft ~ F t, forall a. Eq a => Eq (ft a)) => C t where }}} No extra parameter. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15347#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler