GHC 6.6 panics when compiling HSet from collections package

Adrian Hey ahey at
Wed Jun 13 04:05:52 EDT 2007

Daniel McAllansmith wrote:
> Hi.
> I just got the collections package from 
> 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?

It's a known bug in in ghc 6.6, you need to upgrade to ghc 6.6.1.

BTW, beware of using some of the stuff that I've written for this :-)

The Data.Tree.AVL part (including Data.Map.AVL and Data.Set.AVL)
should be fairly safe as it's been heavily tested.

But the Data.Trie.General part is still under active development,
volatile, unfinished and completely untested.

Also, don't use the Data.Tree.AVL.IntMap stuff either if you can
avoid it. I believe it works fine, but I've decided it would be
best to obsolete this and subsume it within Data.Trie.General
as Data.Trie.General.IntGT

Adrian Hey

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