#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 aaronvargo): To clarify, this also compiles: {{{#!hs class Functor (f :: * -> *) where type Dom f type Cod f liftOb :: ( Functor f, cod ~ Cod f , forall a. Ob (Dom f) a => Ob cod (f a) , Ob (Dom f) a ) => Dict (Ob cod (f a)) liftOb = Dict }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15347#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler