[INFO] updating cached repository https://github.com/djudd/human-name-rb
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 420e24e115b2bd6d102e073c131725ae55d215dc
[INFO] testing djudd/human-name-rb against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdjudd%2Fhuman-name-rb" "work/builds/worker-4/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/djudd/human-name-rb on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/djudd/human-name-rb
[INFO] finished tweaking git repo https://github.com/djudd/human-name-rb
[INFO] tweaked toml for git repo https://github.com/djudd/human-name-rb written to work/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/djudd/human-name-rb already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] c4a22b5ff4359b4d7072c93b1fd5539f2d969d7cf22601bacbde7a3bcdfbfdc6
[INFO] running `"docker" "start" "-a" "c4a22b5ff4359b4d7072c93b1fd5539f2d969d7cf22601bacbde7a3bcdfbfdc6"`
[INFO] [stderr]    Compiling libcruby-sys v0.6.4
[INFO] [stderr]    Compiling cslice v0.3.0
[INFO] [stderr]    Compiling cstr-macro v0.1.0
[INFO] [stderr]    Compiling smallvec v0.6.8
[INFO] [stderr]    Compiling syn v0.15.26
[INFO] [stderr]    Compiling phf_generator v0.7.24
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/smallvec-0.6.8/lib.rs:33:32
[INFO] [stderr]    |
[INFO] [stderr] 33 | #![cfg_attr(feature = "union", feature(untagged_unions))]
[INFO] [stderr]    |                                ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `smallvec`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "c4a22b5ff4359b4d7072c93b1fd5539f2d969d7cf22601bacbde7a3bcdfbfdc6"`
[INFO] running `"docker" "rm" "-f" "c4a22b5ff4359b4d7072c93b1fd5539f2d969d7cf22601bacbde7a3bcdfbfdc6"`
[INFO] [stdout] c4a22b5ff4359b4d7072c93b1fd5539f2d969d7cf22601bacbde7a3bcdfbfdc6