OK, so here's an interesting problem... I've been coding away all day, but now my program is doing something slightly weird. For a specific input, it summarily terminates. The registered exception handler does not fire. There is no output to stdout or stderr indicating what the problem is. It just *stops* half way through the printout. Weirder: If I run it in GHCi, then GHCi itself terminates. (I didn't think you could *do* that!) It's not as if my program is anything unusual. There are no unsafe functions. No FFI. Nothing. Just regular high-level Haskell. Is this a known bug in GHC 6.10.1? Will upgrading fix it? (Obviously, it's quite a lot of work to change GHC.) Suffice it to say that my program is quite big and complicated; it worked fine when it was still small and simple. ;-)