C++ compilers had warnings about infinite recursion for years now (since at least 2015 for clang)

Fair. That's actually crazy - I dug into this more and found the chosen Boost package fails tests on the chosen compiler, and so if they'd done even a cursory check to see if what they're doing could make sense there'd be red flags everywhere.

So the overall story is mostly "Our QA is garbage".

If it's at the "we never compile with -Wall -Werror" level of non-existent QA, I feel like that's an insult to garbage.

-Wall -Werror means that instead of being able to be used as a ratchet the set of "all" warnings in C and C++ became rusted in place. I sympathise with the instinct to write this in your compiler flags, but alas thanks to Hyrum's law this makes the future worse and so today people ask that you -Wextra and no doubt I'll eventually read of how C is fine so long as you -Wall -Wextra -Wevenmore -Wyetmore -Wandthese