Also yeah, antique things like python-2. Which is like the whole reason why keeping a bootstrapping compiler current/modern is important.
Specially for languages like Haskell where Diverse Double Compiling isn't an option.
@lanodan The original compiler used to compile the GCC GNAT was proprietary, and while you can go back to earlier GNAT versions to compile the chain... the original one is obviously missing for a "from source" bootstrap.
@lispi314 Yeah but if you can get GNAT with current GCC via only relying on source code (this exclude transpiled code, as it's not the best/preferred way of doing modifications), then it bootstraps from source, then end. I feel like you're conflating it with ability to go back in history, which is almost the opposite of what I would want.