FWIW, I feel that it's worth just expecting failures with an *optimized* build: with an optimizing compiler, there's likely to always be some program counter location where the debugger is going to get confused for some variables.  Given umpteen different compiler variants, debugger variants etc, this is never going to be perfect.

So IMHO we should run the test on a --pydebug build, but accept that there will be some failures when optimization is on.