id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
2820,GADT code from RepLib causes panic!,ben.kavanagh,,"While compiling RepLib generics library I encountered a ghc panic. I have isolated the failure to very small example that does some simple computation over a heterogenous list. I have attached the following files 

RepMinimal.hs. This is the problem reduced to small example. The function that seems to cause the problem is ""badFunction"". If I remove this function the file compiles.

RepSmall.hs. This is a trimmed down core of RepLib where the original problem occurs. I only include it if someone looking at the bug wants to know what this code was used for.


below is the output of ghc run.
----------------------
[ben@lapdog RepLib]$ ghc -v RepCombined3.hs
Glasgow Haskell Compiler, Version 6.10.1, for Haskell 98, stage 2 booted by GHC version 6.10.1
Using package config file: /usr/lib/ghc-6.10.1/./package.conf
hiding package base-3.0.3.0 to avoid conflict with later version base-4.0.0.0
wired-in package ghc-prim mapped to ghc-prim-0.1.0.0
wired-in package integer mapped to integer-0.1.0.0
wired-in package base mapped to base-4.0.0.0
wired-in package rts mapped to rts-1.0
wired-in package haskell98 mapped to haskell98-1.0.1.0
wired-in package syb mapped to syb-0.1.0.0
wired-in package template-haskell mapped to template-haskell-2.3.0.0
wired-in package dph-seq mapped to dph-seq-0.3
wired-in package dph-par mapped to dph-par-0.3
Hsc static flags: -static
Created temporary directory: /tmp/ghc3284_0
*** Checking old interface for main:Data.RepLib.RepCombined:
*** Parser:
*** Renamer/typechecker:
*** Desugar:
    Result size = 176
*** Simplify:
    Result size = 283
    Result size = 283
*** Tidy Core:
    Result size = 283
*** CorePrep:
    Result size = 465
*** Stg2Stg:
*** CodeGen:
*** CodeOutput:
*** Deleting temp files:
Deleting: /tmp/ghc3284_0/ghc3284_0.s
*** Deleting temp dirs:
Deleting: /tmp/ghc3284_0
ghc: panic! (the 'impossible' happened)
  (GHC version 6.10.1 for i386-unknown-linux):
	initC: srt_lbl

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
----------------------------------
",bug,closed,normal,,Compiler,6.10.1,duplicate,"panic, GADT",,Linux,x86,,Unknown,,,,