Unify with in-tree compiletest-rs

[Manishearth]

I'd like for us to eventually have a world where rustc simply depends on compiletest-rs, and compiletest-rs lives in rust-lang

Blockers:

• [ ] Remove dependency on test crate https://github.com/Manishearth/compiletest-rs/issues/237

[Munksgaard]

I sorta-kinda tried to address this in #201, but never got around to finishing it. My impression was that rustc had some exotic requirements for its internal compiletest that were hard to generalise for this package.

I don't expect I'll get back to working on that PR anytime soon, and it's probably diverged too far from upstream by now to be of any real use, but it is there, if anyone wants to take a look.

[Manishearth]

Yeah I'm wondering if we can keep those requirements but perhaps behind a flag.

[Manishearth]

I really don't want us to have to maintain this as a fork :smile:

[Manishearth]

Instead of doing a merge, we could potentially try a "fresh start" where we first try moving compiletest out of tree, and if that works, release it as a breaking version bump to this crate, making sure major users (clippy, syn) have everything they need to upgrade.

[Munksgaard]

I really don't want us to have to maintain this as a fork smile

Yeah, we should try to minimize the maintenance burden as much as possible.

[Munksgaard]

Instead of doing a merge, we could potentially try a "fresh start" where we first try moving compiletest out of tree, and if that works, release it as a breaking version bump to this crate, making sure major users (clippy, syn) have everything they need to upgrade.

That may not be a bad idea. At least, it's worth a shot :-)

[Manishearth]

Filed rustc side of this issue in https://github.com/rust-lang/rust/issues/82946