ghc-6.8.1 panics compiling regex-tdfa-0.93
This was reported to me by thomas.hartman@db.com
Short summary: The file that dies indicated that use of "mdo" may be the problem, since the file is quite ordinary otherwise.
There is no cut down test case yet. The regex-base and regex-tdfa were pulled from http://darcs.haskell.org/packages/regex-unstable/
> I darcs got the newest regex-tdfa (0.93 iirc) and made all the obvious changes involving LANGUAGE/OPTION_GHC pragmas to get this to work on ghc-6.8.1
>
> prereq regex_base 0.93 installs ok
> regex-tdfa panics with
> hartthoma@linuxpt:~/installs/regexstuff/regex-newest/regex-tdfa>runghc Setup.hs build
> Preprocessing library regex-tdfa-0.93...
> Building regex-tdfa-0.93...
> [ 1 of 21] Compiling Data.IntMap.CharMap ( Data/IntMap/CharMap.hs, dist/build/Data/IntMap/CharMap.o )
>
> Data/IntMap/CharMap.hs:9:27:
> Warning: Imported from `Data.Char' but not used: `chr'
> [ 2 of 21] Compiling Data.IntSet.EnumSet ( Data/IntSet/EnumSet.hs, dist/build/Data/IntSet/EnumSet.o )
> [ 3 of 21] Compiling Data.IntMap.EnumMap ( Data/IntMap/EnumMap.hs, dist/build/Data/IntMap/EnumMap.o )
> [ 4 of 21] Compiling Text.Regex.TDFA.IntArrTrieSet ( Text/Regex/TDFA/IntArrTrieSet.hs, dist/build/Text/Regex/TDFA/IntArrTrieSet.o )
> [ 5 of 21] Compiling Text.Regex.TDFA.Common ( Text/Regex/TDFA/Common.hs, dist/build/Text/Regex/TDFA/Common.o )
> [ 6 of 21] Compiling Text.Regex.TDFA.Pattern ( Text/Regex/TDFA/Pattern.hs, dist/build/Text/Regex/TDFA/Pattern.o )
> [ 7 of 21] Compiling Text.Regex.TDFA.ReadRegex ( Text/Regex/TDFA/ReadRegex.hs, dist/build/Text/Regex/TDFA/ReadRegex.o )
> [ 8 of 21] Compiling Text.Regex.TDFA.CorePattern ( Text/Regex/TDFA/CorePattern.hs, dist/build/Text/Regex/TDFA/CorePattern.o )
> ghc-6.8.1: panic! (the 'impossible' happened)
> (GHC version 6.8.1 for i386-unknown-linux):
> splitFunTy
> <nt>mtl-1.1.0.0:Control.Monad.RWS.Lazy.RWS{tc rsRo}
> (base:Data.Maybe.Maybe{tc r6}
> regex-tdfa-0.93:Text.Regex.TDFA.Common.GroupIndex{tc raaa})
> [base:Data.Either.Either{tc 344}
> regex-tdfa-0.93:Text.Regex.TDFA.Common.Tag{tc raai}
> regex-tdfa-0.93:Text.Regex.TDFA.Common.GroupInfo{tc raa4}]
> ([regex-tdfa-0.93:Text.Regex.TDFA.Common.OP{tc raae}]
> -> [regex-tdfa-0.93:Text.Regex.TDFA.Common.OP{tc raae}],
> regex-tdfa-0.93:Text.Regex.TDFA.Common.Tag{tc raai})
> (base:GHC.Prim.Any{(w) tc 31N},
> [regex-tdfa-0.93:Text.Regex.TDFA.Common.Tag{tc raai}])
>
> Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug