serde_codegen fails to compile on recent nightly with -Z orbit

[alexbool]

When I compile serde_codegen 0.7.8 with -Z orbit on Windows 32-bit, I get this error:

Assertion failed: isa<X>(Val) && "cast<Ty>() argument of incompatible type!", file C:\bot\slave\nightly-dist-rustc-win-msvc-32\build\src\llvm\include\llvm/Support/Casting.h, line 223
Build failed, waiting for other jobs to finish...
error: Could not compile `serde_codegen`.

Meta:

Alexander@VAIO-FZ13 MINGW64 ~
$ rustc -vV
rustc 1.11.0-nightly (1c975eafa 2016-06-05)
binary: rustc
commit-hash: 1c975eafa934e291e4f94b7252faae767de17313
commit-date: 2016-06-05
host: i686-pc-windows-msvc
release: 1.11.0-nightly

The build succeeds at least on OS X.

[retep998]

The biggest codegen difference between -msvc and other targets is the SEH exception stuff, which may be causing this, possibly.

[eddyb]

Hang on, that includes the changes which broke syntex_syntax and which I fixed in #34128.

@alexbool What version did you try on OSX?

[alexbool]

@eddyb version on OS X is:

alexbool@alexbool-osx ~/D/I/serde-codegen-failure> rustc -vV
rustc 1.11.0-nightly (1c975eafa 2016-06-05)
binary: rustc
commit-hash: 1c975eafa934e291e4f94b7252faae767de17313
commit-date: 2016-06-05
host: x86_64-apple-darwin
release: 1.11.0-nightly

[eddyb]

@alexbool Hmm, that's the same version, it shouldn't be able to compile syntex_syntax with RUSTFLAGS=-Zorbit.
Unless version 0.7 is old enough that it doesn't sport struct Name(u32); (that definition used to be type Name = u32; which would explain why it works).

@retep998 started a windows build of #34128, so we might find out soon, one way or another.

[alexbool]

@eddyb I am trying to make a minimal example now, seems that it isn't so easy

[eddyb]

@alexbool A backtrace or the last hundred or so lines from RUST_LOG=rustc_trans::mir could reveal the problem but I doubt either is possible on the MSVC nightly.

[alexbool]

@eddyb UPD only happens on release builds. Minimal example on the way

[alexbool]

Cargo.toml

[package]
name = "serde-codegen-failure"
version = "0.1.0"
authors = ["Alexander Bulaev <alexbool@yandex-team.ru>"]

[dependencies]
serde = "*"
serde_macros = "*"

src/lib.rs

#![feature(custom_derive, plugin)]
#![plugin(serde_macros)]

extern crate serde;

~/.cargo/config

[build]
rustflags = ["-Ctarget-cpu=native", "-Zorbit"]

(removing -Ctarget-cpu=native doesn't help)

Alexander@VAIO-FZ13 MINGW64 ~/serde-codegen-failure (master)
$ cargo build --verbose --release
   Compiling aster v0.17.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\aster-0.17.0\\src\\lib.rs --crate-name aster --crate-type lib -C opt-level=3 -C metadata=8cc5f970a844ae51 -C extra-filename=-8cc5f970a844ae51 --out-dir C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit`
   Compiling quasi v0.11.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\quasi-0.11.0\\src\\lib.rs --crate-name quasi --crate-type lib -C opt-level=3 -C metadata=f0f90e4a9a9f69ab -C extra-filename=-f0f90e4a9a9f69ab --out-dir C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit`
   Compiling serde v0.7.8
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde-0.7.8\\src\\lib.rs --crate-name serde --crate-type lib -C opt-level=3 --cfg feature=\"std\" --cfg feature=\"default\" -C metadata=90f0afafc2b6e513 -C extra-filename=-90f0afafc2b6e513 --out-dir C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit`
   Compiling serde_codegen v0.7.8
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\build.rs --crate-name build_script_build --crate-type bin -C opt-level=3 --cfg feature=\"quasi_macros\" --cfg feature=\"nightly\" --out-dir C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\build\\serde_codegen-9f41a709c17aa9aa --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit`
     Running `C:\Users\Alexander\serde-codegen-failure\target\release\build\serde_codegen-9f41a709c17aa9aa\build-script-build`
   Compiling quasi_codegen v0.11.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\quasi_codegen-0.11.0\\src\\lib.rs --crate-name quasi_codegen --crate-type lib -C opt-level=3 -C metadata=d15a779fc360468f -C extra-filename=-d15a779fc360468f --out-dir C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --extern aster=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps\\libaster-8cc5f970a844ae51.rlib --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit`
   Compiling quasi_macros v0.11.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\quasi_macros-0.11.0\\src\\lib.rs --crate-name quasi_macros --crate-type dylib -C prefer-dynamic -C opt-level=3 -C metadata=30f11f7edf6a7bdc -C extra-filename=-30f11f7edf6a7bdc --out-dir C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --extern quasi_codegen=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps\\libquasi_codegen-d15a779fc360468f.rlib --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit`
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\src\\lib.rs --crate-name serde_codegen --crate-type lib -C opt-level=3 --cfg feature=\"quasi_macros\" --cfg feature=\"nightly\" -C metadata=17040f1a2091a93f -C extra-filename=-17040f1a2091a93f --out-dir C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps --extern quasi=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps\\libquasi-f0f90e4a9a9f69ab.rlib --extern quasi_macros=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps\\quasi_macros-30f11f7edf6a7bdc.dll --extern aster=C:\\Users\\Alexander\\serde-codegen-failure\\target\\release\\deps\\libaster-8cc5f970a844ae51.rlib --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit`
Assertion failed: isa<X>(Val) && "cast<Ty>() argument of incompatible type!", file C:\bot\slave\nightly-dist-rustc-win-msvc-32\build\src\llvm\include\llvm/Support/Casting.h, line 223
error: Could not compile `serde_codegen`.

Caused by:
  Process didn't exit successfully: `rustc C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\src\lib.rs --crate-name serde_codegen --crate-type lib -C opt-level=3 --cfg feature="quasi_macros" --cfg feature="nightly" -C metadata=17040f1a2091a93f -C extra-filename=-17040f1a2091a93f --out-dir C:\Users\Alexander\serde-codegen-failure\target\release\deps --emit=dep-info,link -L dependency=C:\Users\Alexander\serde-codegen-failure\target\release\deps -L dependency=C:\Users\Alexander\serde-codegen-failure\target\release\deps --extern quasi=C:\Users\Alexander\serde-codegen-failure\target\release\deps\libquasi-f0f90e4a9a9f69ab.rlib --extern quasi_macros=C:\Users\Alexander\serde-codegen-failure\target\release\deps\quasi_macros-30f11f7edf6a7bdc.dll --extern aster=C:\Users\Alexander\serde-codegen-failure\target\release\deps\libaster-8cc5f970a844ae51.rlib --cap-lints allow -Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit` (exit code: 3221226505)

[alexbool]

Also build options (-Ctarget-cpu=native -Zorbit -Ctarget-cpu=native -Zorbit) are somehow passed twice, seems like there's also a cargo bug

[eddyb]

@alexbool Isn't it easier to just run RUSTFLAGS=-Zorbit cargo build in serde_codegen's source dir?

[alexbool]

@eddyb Yep, something like this works:

Alexander@VAIO-FZ13 MINGW64 ~/.cargo/registry/src/github.com-1ecc6299db9ec823/serde_codegen-0.7.8
$ cargo build --release --verbose --no-default-features --features "nightly"
   Compiling aster v0.17.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\aster-0.17.0\\src\\lib.rs --crate-name aster --crate-type lib -C opt-level=3 -C metadata=8cc5f970a844ae51 -C extra-filename=-8cc5f970a844ae51 --out-dir C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --cap-lints allow -Ctarget-cpu=native -Zorbit`
   Compiling serde_codegen v0.7.8 (file:///C:/Users/Alexander/.cargo/registry/src/github.com-1ecc6299db9ec823/serde_codegen-0.7.8)
     Running `rustc build.rs --crate-name build_script_build --crate-type bin -C opt-level=3 --cfg feature=\"nightly\" --cfg feature=\"quasi_macros\" --out-dir C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\build\\serde_codegen-da094a7fbaf20dd5 --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps -Ctarget-cpu=native -Zorbit`
   Compiling quasi v0.11.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\quasi-0.11.0\\src\\lib.rs --crate-name quasi --crate-type lib -C opt-level=3 -C metadata=f0f90e4a9a9f69ab -C extra-filename=-f0f90e4a9a9f69ab --out-dir C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --cap-lints allow -Ctarget-cpu=native -Zorbit`
     Running `C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\target\release\build\serde_codegen-da094a7fbaf20dd5\build-script-build`
   Compiling quasi_codegen v0.11.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\quasi_codegen-0.11.0\\src\\lib.rs --crate-name quasi_codegen --crate-type lib -C opt-level=3 -C metadata=d15a779fc360468f -C extra-filename=-d15a779fc360468f --out-dir C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --extern aster=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps\\libaster-8cc5f970a844ae51.rlib --cap-lints allow -Ctarget-cpu=native -Zorbit`
   Compiling quasi_macros v0.11.0
     Running `rustc C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\quasi_macros-0.11.0\\src\\lib.rs --crate-name quasi_macros --crate-type dylib -C prefer-dynamic -C opt-level=3 -C metadata=30f11f7edf6a7bdc -C extra-filename=-30f11f7edf6a7bdc --out-dir C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --extern quasi_codegen=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps\\libquasi_codegen-d15a779fc360468f.rlib --cap-lints allow -Ctarget-cpu=native -Zorbit`
     Running `rustc src\\lib.rs --crate-name serde_codegen --crate-type lib -C opt-level=3 --cfg feature=\"nightly\" --cfg feature=\"quasi_macros\" --out-dir C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release --emit=dep-info,link -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release -L dependency=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps --extern quasi_macros=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps\\quasi_macros-30f11f7edf6a7bdc.dll --extern aster=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps\\libaster-8cc5f970a844ae51.rlib --extern quasi=C:\\Users\\Alexander\\.cargo\\registry\\src\\github.com-1ecc6299db9ec823\\serde_codegen-0.7.8\\target\\release\\deps\\libquasi-f0f90e4a9a9f69ab.rlib -Ctarget-cpu=native -Zorbit`
Assertion failed: isa<X>(Val) && "cast<Ty>() argument of incompatible type!", file C:\bot\slave\nightly-dist-rustc-win-msvc-32\build\src\llvm\include\llvm/Support/Casting.h, line 223
error: Could not compile `serde_codegen`.

Caused by:
  Process didn't exit successfully: `rustc src\lib.rs --crate-name serde_codegen --crate-type lib -C opt-level=3 --cfg feature="nightly" --cfg feature="quasi_macros" --out-dir C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\target\release --emit=dep-info,link -L dependency=C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\target\release -L dependency=C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\target\release\deps --extern quasi_macros=C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\target\release\deps\quasi_macros-30f11f7edf6a7bdc.dll --extern aster=C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\target\release\deps\libaster-8cc5f970a844ae51.rlib --extern quasi=C:\Users\Alexander\.cargo\registry\src\github.com-1ecc6299db9ec823\serde_codegen-0.7.8\target\release\deps\libquasi-f0f90e4a9a9f69ab.rlib -Ctarget-cpu=native -Zorbit` (exit code: 3221226505)

[eddyb]

@alexbool Does this still happen on the latest nightly?

[alexbool]

@eddyb latest nightly broke aster, so nope. I will recheck when it's fixed

[alexbool]

Still reproduces on latest nightly and serde-codegen 0.7.10

[eddyb]

@alexbool Is a debugger's backtrace in this case useless?

[alexbool]

@eddyb What do yo mean with debugger's backtrace?
Also RUST_LOG=rustc_trans::mir seems to do nothing.

[eddyb]

@alexbool I mean gdb or Visual Studio. RUST_BACKTRACE won't do no good because this is not a panic, it's an abort from LLVM.
RUST_LOG doesn't work because debug assertions are not enabled on nightly (cc @alexcrichton 😢).

[retep998]

gdb won't work because it is -msvc. Visual Studio is the best option for getting a backtrace.

[alexbool]

So what should I precisely do? Launch rustc under Visual Studio and then put a breakpoint? Where? Is nightly compiler shipped with debug symbols?

[eddyb]

@alexbool It's not about breakpoints, the debugger will automatically catch the abort. The lack of debug symbols is why I asked whether it's useless.

[alexbool]

OK, I try this later today

[retep998]

Well, since rustc links to dylib versions of the standard library and friends, it actually means that those symbols which are exported from the dylibs can be sometimes found by the debugger when generating a backtrace. Granted proper debug symbols via PDB files are always better but nobody's decided on how to provide a debuginfo package for Rust yet.

[alexbool]

So the backtrace looks like this...

[eddyb]

@alexbool Yeah, that's what I was afraid of :(. Thanks anyway, although I don't have a windows setup to figure this out on.
cc @nikomatsakis

[alexcrichton]

Ok, built a custom compiler with debuginfo and got a stack trace:

I wonder if this is fixed in upstream LLVM...

[alexcrichton]

Oh also oddly enough, for me this was faulting in syntex_syntax rather than serde_codegen, but this was also 64-bit rather than 32-bit which may have changed something.

[eddyb]

@alexcrichton That's really useful, thanks!
Judging from that stack trace, it's likely this cast called from inside SimplifyCFG.
LLVM's Verifier actually checks that the cast would succeed, so either SimplifyCFG is running before the Verifier (in which case trans could be generating bad IR that's not checked on creation) or SimplifyCFG is replacing uses of cleanuppad with something else.

@alexbool @alexcrichton The next step would be to get the last function from the (very verbose!) log produced by compiling with RUSTFLAGS="-Zorbit -Cllvm-args=-print-before-all" (do not set this for any other crate than the failing one, it would probably slow everything down).

[alexbool]

@eddyb It's already compiling for 20 minutes and doesn't want to end. I see you are doing quite a lot of work in the compiler 😄
I'll post the results as soon they are ready

[eddyb]

@alexbool Most of it is just all of the passes that are being ran on all of the LLVM functions, so there's a lot of stuff, and it slows down LLVM, too, sadly. @alexcrichton mentioned on IRC a few hours ago that he started the same thing, but I haven't heard back since.

[alexcrichton]

@eddyb I may miss you on IRC, but I ran with -C llvm-args=-print-before-all yesterday and after running for ~24 hours now it's produced nearly 5GB of output and is still going. I think you can customize which passes you print before, right? Perhaps I should just try printing before the verifier pass if you think that's the one crashing?

[eddyb]

@alexcrichton That's terrible, I'm sorry 😞.
RUSTFLAGS="-Zorbit -Cllvm-args=-print-before=simplifycfg" seems to print what I'm after (judging by the stack trace containing SimplifyCFG in it).

[alexbool]

I'll try it either.

[alexbool]

This is my log compile.log.gz

[eddyb]

@alexbool Thanks! Relevant part: https://gist.github.com/eddyb/ab2e6b1604897e1033f51badb4c4b9fb.

[eddyb]

So it doesn't look like that function is invalid, which means that the function might have significantly changed due to the (possibly incorrect) SimplifyCFG pass.

[eddyb]

@alexbool @alexcrichton Think I found the fix upstream: llvm-mirror/llvm@47bc554.

[alexcrichton]

Ok, @brson and I will work on #34055, and once that's landed we can try to land an LLVM update, and hopefully that'll just magically fix this!

[alexcrichton]

I've added this to the "Launch MIR into Orbit" milestone, but feel free to correct me if that was in error!

[eddyb]

@alexbool Sounds good. What's the status of the LLVM update?

[alexcrichton]

I'm not personally actively working on it, but @brson has posted about it here and here. We may want a little bit of extra coordinate to support both emscripten and AVR, but may just want to coordinate in this thread

[nikomatsakis]

@alexcrichton seems like it qualifies for milestone to me.

[nikomatsakis]

Do we believe that this is platform specific? The original comment mentions that it fails on Windows 32-bit, but not Mac -- what about linux? Other versions of Windows?

[alexbool]

I cannot repriduce this on Linux. Did not try Windows 64 bit

[eddyb]

@alexbool Next nightly (~20h from now) should be fixed. Will close when we have confirmation.

[alexbool]

OK, I'll try

[eddyb]

@alexbool FWIW both @alexcrichton and me and have tried and can't reproduce on beta or nightly.
I also can't reproduce on a local build that includes the LLVM upgrade, so this is most likely fixed now.

[alexbool]

@eddyb I can confirm that with the latest nightly it doesn't reproduce