#8062: Panic "Lookup local fingerprint main:Main.main{v r6xE}" ---------------------------------+------------------------------------ Reporter: tommd | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: fixed | Keywords: Operating System: Linux | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Changes (by tommd): * status: new => closed * resolution: => fixed Comment: This is fixed in head, though the error message is a bit odd. For the curious, a working example is: {{{ {-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeFamilies #-} main = do bench bar :: IO Int return () -- Run the monad, applying the value bench :: Pr c -> IO c bench = undefined -- Protocol monad newtype Pr a = Pr a -- Shared newtype Cont a = Cont a type family S (m :: * -> *) :: * -> * type instance S Pr = Cont bar :: Pr (S Pr a) bar = undefined }}} I'll close the ticket now. Thanks to emertens for working to build the example and test HEAD. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8062#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler