#10503: The impossible happened (no skolem info) - untouchable kind variable -------------------------------------+------------------------------------- Reporter: | Owner: AlekseyKliger | Status: new Type: bug | Milestone: Priority: normal | Version: 7.10.1 Component: Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: Compile-time Architecture: | crash Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE RankNTypes, PolyKinds, DataKinds, TypeFamilies #-} module GHCBug where data Proxy p = Proxy data KProxy (a :: *) = KProxy h :: forall r . (Proxy ('KProxy :: KProxy k) ~ Proxy ('KProxy :: KProxy *) => r) -> r h = undefined }}} GHC reports {{{ GHCBug.hs:8:6: Couldn't match kind ‘k’ with ‘*’ ‘k’ is untouchable inside the constraints (Proxy 'KProxy ~ Proxy 'KProxy) bound by the type signature for h :: (Proxy 'KProxy ~ Proxy 'KProxy) => r at GHCBug.hs:8:6-87ghc: panic! (the 'impossible' happened) (GHC version 7.10.1 for x86_64-unknown-linux): No skolem info: k_amc[sk] }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10503 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler