#15793: Type family doesn't reduce with visible kind application -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 8.6.1 Resolution: invalid | Keywords: | TypeApplications Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by goldfire): * status: new => closed * resolution: => invalid Comment: This is expected behavior. Your `F2` has an arity of 0 and so takes no argument, visible or otherwise. See related discussion in #11719. We don't yet have the syntax to declare a type family whose argument is both invisible and non-dependent. This would work fine internally, but there's just no way to say it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15793#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler