#14968: QuantifiedConstraints: Can't be RHS of type family instances -------------------------------------+------------------------------------- Reporter: josef | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.5 checker) | Keywords: Resolution: | QuantifiedConstraints Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #9269 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I'm lost. Is there some aspect of quantified constraints that would make this OK: {{{#!hs type instance Functors (t ': ts) = (forall f. Functor f => Functor (t f), Functors ts) }}} But not this (from https://ghc.haskell.org/trac/ghc/ticket/9269#comment:1)? {{{#!hs type instance Foo True = forall a. a -> a -> a }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14968#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler