IMHO, really there are no options for this idea other than to be disappointing. C++ is already a monster, way too complex and complicated, and unless one decides to revamp it from the ground up, effectively coming up with a different language that is no longer C++, the only way to improve the safety is to make C++ even more complex and complicated. I think in 202x's it's time to let it go, to stop layering complications and inconsistencies on top of one another. To continue trying to "fix" C++ is to continue to feed the sunk cost fallacy.