The bug I think I've spent most time on was when my Racket program would run for a while and then segfault randomly. Core dumps showed a stack overflow, but uns

The bug I think I've spent most time on was when my Racket program would run for a while and then segfault randomly. Core dumps showed a stack overflow, but unsurprisingly, examining the racket source code didn't enlighten me. I had to git bisect through a number of commits, running them on several instances and tentatively marking them 'good' if I didn't find anything after a few hours. (One time I was too quick to mark a commit 'good'...) The guilty commit seemed fairly innocent, but it prompted me to try running `(loop (thread (const null)))`, which immediately segfaulted. `(loop (thread (thunk null)))` didn't. At this point we handed off to the racket devs, and replaced our `(const null)` callbacks with `(thunk null)`. After a few days they worked out what was going on and fixed it.