Hi Mark, A while ago, it looked we had a few regressions in the compiler regarding stack consistency: ticket #89 and the issue reported by Alan (PROGV inside AND). The former you ran into when trying to get ASDF2 running on ABCL. As it turned out, these were both were not regressions, but very old bugs. Both are fixed too. For ticket 89, you implemented a work-around, where the compiler would ask the user to replace the compiled form with an interpreted version. Other than this question, are there any side effects of your change? Anything we might want to consider reverting before our next release? Regards, Erik.