ghc panic (applyTypeToArgs) building hledger with -O

[simonmic]

$ cabal install -fweb -fvty -fchart --constraint 'template-haskell < 2.4'
Resolving dependencies...
Configuring hledger-0.8...
Preprocessing library hledger-0.8...
Preprocessing executables for hledger-0.8...
Building hledger-0.8...
ar: creating archive dist/build/libHShledger-0.8.a
[29 of 32] Compiling Commands.Convert ( Commands/Convert.hs, dist/build/hledger/hledger-tmp/Commands/Convert.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 6.10.4 for i386-apple-darwin):
	applyTypeToArgs
    parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.a32{v rwo} [gid]
      @ csv-0.1.1:Text.CSV.CSV{tc r2Ve}
      (csv-0.1.1:Text.CSV.a22{v r2Va} [gid]
       `cast` (ghc-prim:GHC.Prim.sym{(w) tc 34v}
                 ((parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.:CoGenParser{tc rhR})
                    ghc-prim:GHC.Types.Char{(w) tc 3o}
                    ghc-prim:GHC.Unit.(){(w) tc 40}
                    csv-0.1.1:Text.CSV.CSV{tc r2Ve})
               :: <pred>parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.State{tc rhV}
                          ghc-prim:GHC.Types.Char{(w) tc 3o} ghc-prim:GHC.Unit.(){(w) tc 40}
                        -> parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.Consumed{tc rit}
                             (parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.Reply{tc ris}
                                ghc-prim:GHC.Types.Char{(w) tc 3o}
                                ghc-prim:GHC.Unit.(){(w) tc 40}
                                csv-0.1.1:Text.CSV.CSV{tc r2Ve})
                          ~
                        parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.GenParser{tc rhk}
                          ghc-prim:GHC.Types.Char{(w) tc 3o}
                          ghc-prim:GHC.Unit.(){(w) tc 40}
                          csv-0.1.1:Text.CSV.CSV{tc r2Ve}))
      csvfile{v s3Vz} [lid]
    forall st{tv i3Im} [tv] a{tv i3In} [tv].
    parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.GenParser{tc rhk}
      csv-0.1.1:Text.CSV.CSV{tc r2Ve} st{tv i3Im} [tv] a{tv i3In} [tv]
    -> [base:GHC.Base.String{tc 36u}]
    -> parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.State{tc rhV}
         csv-0.1.1:Text.CSV.CSV{tc r2Ve} st{tv i3Im} [tv]
    -> parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.Consumed{tc rit}
         (parsec-2.1.0.1:Text.ParserCombinators.Parsec.Prim.Reply{tc ris}
            csv-0.1.1:Text.CSV.CSV{tc r2Ve} st{tv i3Im} [tv] a{tv i3In} [tv])

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

Seen for the first time today. Does not happen when using ghc --make.

[simonmic]

Happens with -O. Another way to reproduce:

$ darcs get --lazy  http://joyful.com/repos/hledger && cd hledger $ ghc --make Commands/Convert.hs -O

[simonpj]

I suspect this is fixed in 6.12 (see eg #3528), but I couldn't try it because I get this when installing dependencies. Maybe HUnit isn't 6.12 compatible.

cabal install --with-ghc=$head1 --user HUnit
Resolving dependencies...
Downloading HUnit-1.2.0.0...
Configuring HUnit-1.2.0.0...
Preprocessing library HUnit-1.2.0.0...
Building HUnit-1.2.0.0...
[1 of 5] Compiling Test.HUnit.Terminal ( Test/HUnit/Terminal.lhs, dist/build/Test/HUnit/Terminal.o )
[2 of 5] Compiling Test.HUnit.Lang  ( Test/HUnit/Lang.lhs, dist/build/Test/HUnit/Lang.o )

Test/HUnit/Lang.lhs:23:43:
    Module `Control.Exception' does not export `throwDyn'
cabal: Error: some packages failed to install:
HUnit-1.2.0.0 failed during the building phase. The exception was:
ExitFailure 1
bash-3.2$ 

Would you like to try with 6.12?

Simon

[simonmic]

Thank you, unfortunately things my app depends on don't yet work in the 6.12 world and I want to do one more 6.10-based release. This started recently so I'll look a bit harder for a workaround.

[simonmic]

Workaround found. I had:

$ ghc-pkg list parsec /opt/local/lib/ghc-6.10.4/./package.conf:

parsec-2.1.0.1

/Users/simon/.ghc/i386-darwin-6.10.4/package.conf:

parsec-2.1.0.1

The issue happens when I have cabal installed parsec in the --user space. Unregistering that one and relying on the parsec that came with the ghc binary installer made the problem go away.

[simonmar]

Ah, so you probably had an inconsistency in your package dependencies. GHC 6.12 would have detected and reported it, probably.

Optimistically closing, in anticipation that 6.12 would give a better error message.