Strange behavior in GHC-compiled code

Malcolm Wallace malcolm.wallace at
Fri May 25 18:53:52 CEST 2012

Unless you show us the code, any answers will be guesses in the dark.  Does your program use unsafePerformIO unsafely perhaps?  Or a version of a library that happens to have a known bug?

On 25/05/2012, at 14:33, Mark Conway Wirt <MarkCWirt at> wrote:

> I have a piece of Haskell code that's been laying around on my computer
> for about a year, and I recently decided to dust it off.
> The problem is that it used to work fine, but in the interim (in which
> I both upgraded OS versions/GHC versions and went from 32 bit to 64 bit)
> the code stopped working reliably.  [...]
> Any guidance/pointers would be very much appreciated.

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