When a problem with stepping is detected there are two choices:
-> try to keep going
+ sometimes the stepper recovers (making things look better than they are)
- sometimes it doesn't (instead program is stepped into the weeds making things
look buggy) -> no possible recovery
-> stop immediately and report problem
- can leave the program in strange locations (making things look more buggy than
they are) -> recovery is to "step -i"
+ can't over-step or run into the weeds
While it is possible to work-around a stepping engine that stops early, it is
difficult to work-around one that keeps running into the weeds.