#9222: Unexpected DataKind Panic -------------------------------------------+------------------------------- Reporter: ekmett | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type checker) | Version: 7.8.2 Keywords: | Operating System: Architecture: Unknown/Multiple | Unknown/Multiple Difficulty: Unknown | Type of failure: Blocked By: | None/Unknown Related Tickets: | Test Case: | Blocking: -------------------------------------------+------------------------------- Here's a simplified version of a panic I'm getting: {{{ {-# LANGUAGE RankNTypes, GADTs, DataKinds, PolyKinds, TypeOperators, TypeFamilies #-} import Data.Proxy data Want :: (i,j) -> * where Want :: (a ~ '(b,c) => Proxy b) -> Want a }}} {{{ GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. ghc: panic! (the 'impossible' happened) (GHC version 7.8.2 for x86_64-apple-darwin): tcTyVarDetails k{tv aAv} [tv] Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9222 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler