This is from cargo test, apparently due to the generator crate, brought in via loom. Example CI failure. This is because asm! is being renamed to llvm_asm! (tracking issue).
Possible solutions:
generator cratecfg away the asm! code. I'm not sure if loom even uses that stuff.loom on nightlyWe should probably file it to the generator crate, unless it's filed already.
Fair enough. I made PR https://github.com/Xudong-Huang/generator-rs/pull/20 to fix the issue, so hopefully it should be a matter of waiting until that change is merged and propagated upwards.
Now that generator has released 0.6.21, this is fixed. 馃憤