Is it possible to generate this automatically using conformance tests?

There are a handful of commercial offerings of C++ conformance test suites. They're all generally around 40000 euro for an evaluation copy (more for an actual full licensed copy), none are 100% complete, and we continually find bugs in tests.

You're not going to find some hobbyist coming up with a useful conformance or coverage test suite for free. It's intensive, expensive, and arduous.

Such things are mandatory, however, if you are a C++ vendor targeting ISO 26262 or IEC 61508 or similar -- basically, software that could kill you if it's done wrong. It's a niche with money and motivation.

Having something like WPT [1] for C++ would be really nice.

[1] https://github.com/web-platform-tests/wpt

Hi! That's certainly possible, and also what I'm already doing. However, it's very time-consuming to do it for every single feature. The compiler vendors already provide their feature-support tables for most features, which I've made a small bot for that watches for conformance changes. For feature support that is unclear or not provided by the vendors, I write conformance tests to verify. In my experience, this mix works best.