#10960: Closed type families don't reduce on data family instances -------------------------------------+------------------------------------- Reporter: exFalso | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: duplicate | Keywords: closed type | family data Operating System: Linux | Architecture: x86_64 Type of failure: GHC rejects | (amd64) valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by exFalso): A note to anyone encountering this same problem: There is a weird workaround, at least for the above problem: {{{#!hs type family T a where T () = () T (f a) = Char -- (D ()) reduces here T a = Char }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10960#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler