#8953: Reifying poly-kinded type families misses kind annotations -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Template | Version: 7.9 Haskell | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: | Related Tickets: None/Unknown | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by goldfire): Urgh. This gets even worse. Look at this: {{{ {-# LANGUAGE DataKinds, PolyKinds, TypeFamilies, TemplateHaskell #-} import Language.Haskell.TH import Data.Proxy type family Silly :: k -> * type instance Silly = (Proxy :: * -> *) type instance Silly = (Proxy :: (* -> *) -> *) $( do info <- reify ''Silly runIO $ putStrLn $ pprint info return [] ) }}} This produces {{{ type family Main.Silly :: k_0 -> * type instance Main.Silly = Data.Proxy.Proxy type instance Main.Silly = Data.Proxy.Proxy }}} Now, there's no variables to annotate! I think the thing to do is to kind- annotate every poly-kinded tycon application, ''and'' every variable on the LHS whose kind includes a kind variable. I guess this conclusion is a bare-bones attempt at the "inference" described in comment:1, but it seems straightforward enough to implement. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8953#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler