Hi. I just got the collections package from http://darcs.haskell.org/packages/collections-ghc6.6 When trying to build it with GHC 6.6 on an amd64 linux machine using Cabal I got the following: [12 of 57] Compiling Data.Tree.AVL.IntMap.Internals.HSet ( Data.Tree.AVL.IntMap/Data/Tree/AVL/IntMap/Internals/HSet.hs, dist/build/Data/Tree/AVL/IntMap/Internals/HSet.o ) ghc-6.6: panic! (the 'impossible' happened) (GHC version 6.6 for x86_64-unknown-linux): cgPanic tpl{v s2zg} [lid] static binds for: collections-0.3:Data.Tree.AVL.IntMap.Internals.HSet.intersectionMaybeH{v rji} [gid] collections-0.3:Data.Tree.AVL.IntMap.Internals.HSet.$Lr2jfforkL{v r2jf} [gid] collections-0.3:Data.Tree.AVL.IntMap.Internals.HSet.$Lr2jhforkR{v r2jh} [gid] local binds for: SRT label collections-0.3:Data.Tree.AVL.IntMap.Internals.HSet.intersectionWithH'{v rjg}_srt Anyone seen this before? A real GHC bug, a problem with my GHC installation, or a problem with the collections package? Cheers Daniel