#15691: Marking Pred(S n) = n as injective -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.6.1 Component: Compiler (Type | Version: 8.6.1 checker) | Keywords: TypeFamilies, Resolution: invalid | InjectiveFamilies 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 goldfire): There are no current plans to implement "Constrained Type Families". The natural way to do it requires dependent types (because it requires the appearance of dictionaries, which are terms, in types). We could hack something together that didn't use dependent types, but it would be a hack. I would love to see Constrained Type Families indeed implemented once we have dependent types. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15691#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler