#8461: Panic (on woefully incorrect code) -----------------------------------+--------------------------------------- Reporter: srhb | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time crash Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -----------------------------------+--------------------------------------- The following (very wrong) code causes a panic. The haskeline hackage package is required. {{{ import System.Console.Haskeline import Control.Monad.State.Strict main = runStateT (runInputT settings loop) 0 where loop = do minput <- lift getInputLine "% " loop settings :: Settings (StateT Int IO) settings = setComplete comp defaultSettings comp _ = do n <- get put (n+1) return ("", [Completion (show n) "" True]) }}} The error: {{{ [1 of 1] Compiling Main ( test.hs, test.o ) test.hs:7:20: Couldn't match kind `* -> *' with `*' Expected type: [Char] -> InputT m0 (Maybe String) Actual type: [Char] -> InputT m0 (Maybe String) Kind incompatibility when matching types: [Char] :: * -> * [Char] :: * The function `lift'ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for x86_64-unknown-linux): kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d} Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} PS: It was not clear to me whether to call this a compile-time crash or not. All I know is that the 'impossible' happened. :) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8461 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler