Re: the impossible happened

On Mon, May 23, 2005 at 09:38:58AM +0100, Simon Peyton-Jones wrote:
> This "fromJust" bug is SourceForge 1177320.
> 
> The trouble is that we've been unable to reproduce it here.  It seems to
> show up when compiling some large thing, like Darcs or WASH.
> 
> If anyone would be willing to snapshot a tree exhibiting the bug, and
> send it to us, we'd love to investigate.  Until then we're a bit stuck.

It seems that there are not that many uses of fromJust in GHC's sources.
I guess that removing them or at least making them report a source
location in case of failure (for example using a CPP macro like in
darcs) would be an good task for a wannabe GHC hacker. Unfortunately,
I can't volunteer at this moment.

Best regards
Tomasz