ghc panic

[jorzo]

ghc-6.8.3: panic! (the 'impossible' happened)

(GHC version 6.8.3 for powerpc-apple-darwin):

parser/Ctype.lhs:(91,13)-(347,35): Non-exhaustive patterns in case

I've been getting intermittent hangs or crashes from GHC such as the error message above. When I restart the build, it successfully compiles. I did not observe this for ghc 6.8.2 on intel. I only observe it for ghc 6.8.3 for ppc which I am running under the Rosetta JIT compiler in order to cross compile to ppc binaries from an intel macintosh.

[jorzo]

Also,

ghc-6.8.3: internal error: resurrectThreads: thread blocked in a strange way

(GHC version 6.8.3 for powerpc_apple_darwin) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug

[simonmar]

It sounds very much like you're experiencing random corruption, such as you might get from bad hardware. Since you're running under an emulator, I'd immediately suspect either the emulator or your hardware. Can you eliminate either of these?

[mokeefe]

On Mac OS 10.5.6 using XCode 3.1.2, when trying to compile the GHC 6.10.1 sources, I get the below error. Note that what prompted me to try to compile the GHC 6.10.1 sources is an error I received when trying to install cabal-install with the GHC 6.10.1 binaries available as a community build. I will report that as a separate issue.

ghc-6.10.1 $ make grep: packages: No such file or directory make -C libraries boot rm -f -rf ifBuildable mkdir ifBuildable cp ifBuildable.hs ifBuildable/ cd ifBuildable && /usr/local/bin/ghc -Wall --make ifBuildable -o ifBuildable [1 of 1] Compiling Main ( ifBuildable.hs, ifBuildable.o ) Linking ifBuildable ... mkdir bootstrapping /usr/local/bin/ghc -Wall -DCABAL_VERSION=1,6,0,1 -odir /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping -hidir /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping -i/Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal -i/Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/filepath -i/Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/hpc --make cabal-bin -o cabal-bin [ 1 of 54] Compiling Distribution.Compat.Permissions ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/Compat/Permissions.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/Compat/Permissions.o ) [ 2 of 54] Compiling System.FilePath?.Windows ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/filepath/System/FilePath/Windows.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/System/FilePath/Windows.o ) [ 3 of 54] Compiling System.FilePath?.Posix ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/filepath/System/FilePath/Posix.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/System/FilePath/Posix.o ) [ 4 of 54] Compiling Distribution.Compat.Exception ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/Compat/Exception.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/Compat/Exception.o ) [ 5 of 54] Compiling Distribution.Compat.TempFile? ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/Compat/TempFile.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/Compat/TempFile.o ) [ 6 of 54] Compiling Distribution.GetOpt? ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/GetOpt.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/GetOpt.o ) [ 7 of 54] Compiling Distribution.Compat.ReadP ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/Compat/ReadP.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/Compat/ReadP.o ) [ 8 of 54] Compiling Distribution.ReadE ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/ReadE.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/ReadE.o ) [ 9 of 54] Compiling Distribution.Simple.PreProcess?.Unlit ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/Simple/PreProcess/Unlit.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/Simple/PreProcess/Unlit.o ) [10 of 54] Compiling Distribution.Simple.GHC.Makefile ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/Simple/GHC/Makefile.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/Simple/GHC/Makefile.o ) [11 of 54] Compiling Distribution.Text ( /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/Cabal/Distribution/Text.hs, /Users/michaelokeefe/Downloads/ghc-6.10.1/libraries/bootstrapping/Distribution/Text.o ) ghc-6.8.3: panic! (the 'impossible' happened)

(GHC version 6.8.3 for powerpc-apple-darwin):

divide by zero

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

[igloo]

I'm closing this ticket, as it seems likely the issues the original reporter faced were due to the emulator, and we've heard nothing for several months.

mokeefe, if you want to report a different issue then please open a new ticket. However, your problem isn't ringing any bells with me, so I'd recommend upgrading to 6.10.1 (using the installer on the download page) and see if the problem happens again.