When I load my program, GHC spits these messages at me, but doesn't fail Any idea what might be causing this or how to figure that out? Var/Type length mismatch: [] [a{tv aGIf} [tau]] ... Var/Type length mismatch: [] [a{tv aGN8} [tv]] ... I found the responsible code in GHC's darcs, but the context didn't lend any help my feeble non-GHC hacker brain. My program is kind of big and I'm using personal libraries that exercise the type system a lot, but I'll wait to see if anyone is interested or if this has been handled before I share the gory details. This tidbit might help: I have a couple of usages of undefined in my program b/c I'm just starting to code and if I replace a particular undefined of this with some typed dummy code, it removes the second set of mismatches, but not the first. I tried also replacing the other undefined, but the first set of mismatches remained. Glasgow Haskell Compiler, Version 6.7.20070214, for Haskell 98, compiled by GHC version 6.7.20070214 Also, is there a better list for this question? I half-heartedly tried haskell.org's list of mailing lists for an appropriate place for GHC bugs but didn't find one. Thanks for your time, Nick