@bors r+ rollup

📌 Commit 139ef75 has been approved by Mark-Simulacrum

Will this mean that there's no way to just clean the library/compiler artifacts? ./x.py clean && ./x.py check will now take a lot longer if it has to entirely re-build bootstrap first...

Hm, I'd expect bootstrap to compile in around a minute, but I guess maybe it's grown over time. Probably we want some kind of flags or something...

A minute is a lot, since x.py check is rather fast.

Will this mean that there's no way to just clean the library/compiler artifacts?

@RalfJung you could run rm -r build/$TARGET/stage1* (or any other folders you want to clean), would that work? I would rather not make clean too complicated.

That said I guess a reasonable question might be - why do we want to clean bootstrap? It should be very reliably recompiled (unlike other artifacts some times)

@jyn514 yeah that's what I used to do; `x.py clean is much shorter though. ;)

@Mark-Simulacrum one good reason to clean bootstrap is to remove outdated artifacts. When the beta compiler gets bumped, the old files remain, so the bootstrap folder keeps growing and I sometims remove it manually. I do that much less often than x.py clean, though.

It seems like we could delete the bootstrap build directory when the bootstrap compiler changes without too much trouble. If that's the only reason to want to touch it, I think it's better.