I yearn for compilers that can break backwards-compatiblity and strictly enforce best practices. This should be a achieved with a relatively simple command line flag to the compiler (instead of hunting for the right combination of dozens of -Werror=*, which then still let a lot of unclean code through)
Won't see widespread usage outside of learning because you can no longer trust any compiler upgrade not requiring a rewrite to your code, as it arbitrarily decides what the latest best practice.
What might be useful though is something like -wall printing all flags representing current best practices, so you can have a snapshot of it when writing new code (the problem with current -wall is again potentially arbitrary changes on compiler updates as new warnings get added, if it actually did warn on everything)
Then you can choose when you want to update to whatever modern best practices
That would be fine! Although, I also don't think "best practices" would be something that changes every 6 months (maybe every 5 years), and being forced by the compiler to rewrite code to keep up with best practices is absolutely a good thing!
I've been the lead on a fairly large Fortran project, and we make a point to run our test suite on as many compilers as possible, with the strictest flags to avoid any kind of "undefined" behavior (which is rarer in Fortran than in C). I believe it's the only way to ensure long term maintainability.
