While exploring #1086, I realized that tracing had degraded to the point of only working in the interpreter again, even though logic exists to be able to trace in compiled code. The primary reason for this is due to the fact that compiled code has never gained the ability to update our artificial backtrace.

This is not a great deal of work, but it will be a little fiddly. At minimum, the following need to happen:

• The wrappers for compiled methods and blocks need to do c_call (and b_call for blocks). This may still be working, but it depends on backtrace being up to date.
• Compiled wrappers must push and pop backtrace when tracing is enabled.
• Compiled code must update line number as the line progresses.

With these in place I believe it's possible to have compiled tracing work properly.

Of course, if we just wrote our own debugger, this might be a moot point.