#9258: Type inference fails with closed type families -------------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by jstolarek): I'm not an expert here, but it looks like you expect GHC to infer the arguments of s type family based on its result. I believe that's not possible in general and my guess is that GHC doesn't even try, even for a trivial case such as yours. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9258#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler