#14887: Explicitly quantifying a kind variable causes a type family to fail to typecheck -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.2.2 checker) | Keywords: TypeFamilies, Resolution: | TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): The #12919 patch has landed. Interestingly, the program in comment:1 now gives a different error: {{{ $ ~/Software/ghc/inplace/bin/ghc-stage2 --interactive Bug.hs GHCi, version 8.5.20180403: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug.hs, interpreted ) Bug.hs:10:43: error: • Expected kind ‘k’, but ‘a’ has kind ‘k0’ • In the first argument of ‘Proxy’, namely ‘(a :: k)’ In the kind ‘Proxy (a :: k)’ | 10 | type family Foo2 (k :: Type) (e :: Proxy (a :: k)) :: Type where {} | ^ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14887#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler