OK I've fixed this. Thanks for identifying it Simon
| -----Original Message----- | From: Samuel Bronson [mailto:[EMAIL PROTECTED] | Sent: 04 November 2006 23:55 | To: [EMAIL PROTECTED]; Simon Peyton-Jones | Subject: obscure impossible problem with simplifier | | I think the simplifier is doing something iffy with types, because | when I try to call exprType from SimplUtils.interestingArg, I get | this: | | ghc-6.5: panic! (the 'impossible' happened) | (GHC version 6.5 for i386-unknown-linux): | applyTypeToArgs | a98{v a1eB} [lid] ex{v aqZ} [lid] | a{tv a1et} [tv] | | Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug | | make: *** [GHC/TopHandler.o] Error 1 | | I think you only need to add this code: | | interestingArg expr | pprTrace "interestingArg" (ppr expr) $ | isUnLiftedType (exprType expr) = | -- Unlifted args are only ever interesting if we know what | they are | case expr of | Lit lit -> True | _ -> False | | at the top of the "interestingArg" function to get this error. | The call chain looks like: | completeCall -> interestingArg -> exprType -> applyTypeToArgs | | I think somehow an ill-typed variable has been stuffed into the | SimplCont? Or perhaps contArgs isn't substituting right? Anyway I | can't find anything in the immediate area to indicate what the problem | might be caused by... and I really hope it *is* a bug. | | Btw, here is some relevant trace info: | | completeCall | var: base:GHC.IOBase.>>{v rgF} [gid] | cont: ApplyTo nodup TYPE base:GHC.Base.(){(w) tc 40} | ApplyTo nodup TYPE a{tv a13f} [sk] | ApplyTo nodup handler{v ar2} [lid] ex{v aqZ} [lid] | ApplyTo nodup lvl_s1dT{v} [lid] @ a{tv a13f} [sk] | CoerceIt (base:GHC.IOBase.:CoIO{tc r3v}) a{tv a13f} [sk] | ApplyTo nodup new_s{v a1eg} [lid] | Stop[arg] (# base:GHC.Prim.State#{(w) tc 32q} | base:GHC.Prim.RealWorld{(w) tc 31E}, | a{tv a13f} [sk] #) | contArgs | -> ([TYPE base:GHC.Base.(){(w) tc 40}, TYPE a{tv a13f} [sk], | a98{v a1eh} [lid] ex{v aqZ} [lid], | lvl_s1dT{v} [lid] @ a{tv a13f} [sk]], | CoerceIt (base:GHC.IOBase.:CoIO{tc r3v}) a{tv a13f} [sk] | ApplyTo nodup new_s{v a1eg} [lid] | Stop[arg] (# base:GHC.Prim.State#{(w) tc 32q} | base:GHC.Prim.RealWorld{(w) tc 31E}, | a{tv a13f} [sk] #)) | | If you can guess what that might mean, great. If not, well, you could | do your own tracing. Now if you'll excuse me I have a headache :-(. | Potentially related to trying to follow the simplifier. | | This definately didn't happen before the recent simplifier changes. _______________________________________________ Cvs-ghc mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/cvs-ghc
