Current beta breaks my build that works on stable

[Xaeroxe]

Current beta compiler is segfaulting when attempting to build my project that previously worked on stable: https://travis-ci.org/Xaeroxe/nitro-game-engine/builds/211212522

[Xaeroxe]

It's also worth noting: This only happens on Linux and OSX. My Windows build works fine still.

[Xaeroxe]

Same commit on AppVeyor: https://ci.appveyor.com/project/Xaeroxe/nitro-game-engine/build/1.0.45

[nagisa]

Stack overflow building MIR. Looking into it more.

[Xaeroxe]

This project is pretty reliant on generics and auto-generated code so I'm not entirely surprised that's the cause.

[nagisa]

Does not reproduce on a nightly build of my own, but reproduces just fine on the most recent nightly from bots. Ugh!

That does suggest some stupid decisions being made by the optimiser. I feel like at this point just marking a bunch of functions in mir build no-inline would fix a lot of our problems wrt this.

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The workaround is to set RUST_MIN_STACK environment variable to some large value (such as 32MiB (worked for me), currently stack defaults to 16MIB). Due to release happening today, this regression will slip into stable.

[nagisa]

To compare, my local build easily handles 3000 frames on 8MiB stack, whereas with our binary distribution builds there’s approx 500 stack frames on a 16MiB stack.

(8MiB here is comparison point because that’s what overflow stacks locally for me as well)

[Xaeroxe]

Well thanks for the workaround. Evidently I didn't report this fast enough, so my bad there.

[Xaeroxe]

So some notes: It seems I did this build in the middle of today's release.

Rust 1.15 yesterday's stable - works
Rust 1.16 today's stable - works
Rust 1.17 today's beta - doesn't work

Meaning we still have another 6 weeks before this bug would hit stable.

[nikomatsakis]

triage: P-high