id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
737,Pattern match failure in coreSyn/CoreUtils.lhs,ekarttun@…,,"This seems to fail with 6.4.1, and 6.5 too, works fine in ghci.

{{{
e@yui:~/CONFI/nir$ ghc -c -no-recomp bug.hs 
ghc-6.4.2.20060328: panic! (the `impossible' happened, GHC version 6.4.2.20060328):
        coreSyn/CoreUtils.lhs:(617,36)-(618,71): Non-exhaustive patterns in case


Please report this as a compiler bug.  See:
  http://www.haskell.org/ghc/reportabug
}}}


{{{
{-# OPTIONS -fglasgow-exts -O2 #-}

data IHandler st where
    IHandler :: Serialize (TxContext ev) => String -> IO ev -> (res -> IO ()) -> Ev st ev res -> IHandler st

data Ev st ev res  = Ev
data TxContext evt = TxContext
data TxConfig      = TxConfig
data M    a        = M a

class Serialize a where
instance Serialize a => Serialize (TxContext a)
instance Serialize Int
instance Serialize ()

data IHR st = forall res ev. Serialize (TxContext ev) => IHR (TxContext ev) 


runHandler :: M (IHR st) ->  IHandler st -> IO ()
runHandler queue ih@(IHandler tstring inp out run) = do
  runHandler queue ih

main = runHandler undefined $ IHandler ""foo"" (return ()) undefined undefined

}}}",bug,closed,normal,,Compiler,6.4.1,fixed,,,Unknown/Multiple,Unknown/Multiple,,Unknown,,,,