id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
3801,ghc-6.10.4: internal error: PAP object entered,patrikja,,"Running the compiled code for a simple program using WX Haskell + QuickCheck gives ""internal error: PAP object entered"". (I cannot submit the source code openly right now  because it is a solution to course homework in the course I'm teaching Jan-March, but I could send it to whoever is assigned to this bug. Just ask patrikja+ghc AT gmail .)

The error appeared after adding a dependency on QuickCheck (in base) and the Control.Monad.Writer (in mtl) - before that it compiled and worked fine. 

Searching the trac history most PAP object entered seem to refer to http://hackage.haskell.org/trac/ghc/ticket/1372 but I'm not sure how to make sure no ""mismatched library versions"" are around. I'd be happy to rebuild / reinstall my whole cabal library setup if there is an easy way to do that.

Another clue may be the libstdc++.so.6 warning I get after each compile - see below. (That warning has been there also for all the working versions of the code so I'm not sure if it is relevant here.)
{{{
patrikj@hel:~/src/gitroot/edu/AFP/Lab1_turtle$ make test
ghc -package wx --make Lab1_Part2_Task2
[1 of 3] Compiling Turtle           ( Turtle.lhs, Turtle.o )
[2 of 3] Compiling Spiral           ( Spiral.lhs, Spiral.o )
[3 of 3] Compiling Main             ( Lab1_Part2_Task2.lhs, Lab1_Part2_Task2.o )
Linking Lab1_Part2_Task2 ...
/usr/bin/ld: warning: libstdc++.so.6, needed by /usr/lib/libwx_baseu-2.8.so, may conflict with libstdc++.so.7
./Lab1_Part2_Task2 0 91
Lab1_Part2_Task2: internal error: PAP object entered!
    (GHC version 6.10.4 for i386_unknown_linux)
    Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
make: *** [test] Avbruten (SIGABRT)

patrikj@hel:~/src/gitroot/edu/AFP/Lab1_turtle$ uname -a
Linux hel 2.6.31-16-generic #53-Ubuntu SMP Tue Dec 8 04:01:29 UTC 2009 i686 GNU/Linux
}}}
",bug,closed,normal,,Compiler,6.10.4,invalid,,,Linux,x86,Runtime crash,,,,,