id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
1718	6.8.0.20070917 ghc.exe: panic! (the 'impossible' happened)	guest	simonpj	"(From Adrian Hey) Here's the error:

{{{
[29 of 53] Compiling Data.Tree.AVL.Join ( Data.Tree.AVL/Data/Tree/AVL/Join.hs, dist\build/Data/Tree/AVL/Join.o )
ghc.exe: panic! (the 'impossible' happened)
  (GHC version 6.8.0.20070917 for i386-unknown-mingw32):
	cgPanic
    a{v sMX} [lid]
    static binds for:
    collections-0.3:Data.Tree.AVL.Join.poly_go{v rse} [gid]
    collections-0.3:Data.Tree.AVL.Join.poly_$wlgo{v rsf} [gid]
    collections-0.3:Data.Tree.AVL.Join.flatConcat{v ryL} [gid]
    local binds for:
    SRT label collections-0.3:Data.Tree.AVL.Join.$LrMelvl{v rMe}_srt

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

This will probably reproduce it, but it's not quite what I did:

1 - darcs get http://darcs.haskell.org/packages/collections-ghc6.6/

2 - Edit collections.cabal so you have:

{{{build-depends:  base >= 2.0, QuickCheck, bytestring, containers, array}}}

3 - runghc Setup.hs configure

4 - runghc Setup.hs build"	bug	closed	high	6.8.1	Compiler	6.8	fixed			Windows	x86_64 (amd64)		Unknown	simpl018