[INFO] crate pkg 2.0.1 is already in cache
[INFO] extracting crate pkg 2.0.1 into work/ex/beta-1.38-1/sources/1.37.0/reg/pkg/2.0.1
[INFO] extracting crate pkg 2.0.1 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/pkg/2.0.1
[INFO] validating manifest of pkg-2.0.1 on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of pkg-2.0.1 on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing pkg-2.0.1
[INFO] finished frobbing pkg-2.0.1
[INFO] frobbed toml for pkg-2.0.1 written to work/ex/beta-1.38-1/sources/1.37.0/reg/pkg/2.0.1/Cargo.toml
[INFO] started frobbing pkg-2.0.1
[INFO] finished frobbing pkg-2.0.1
[INFO] frobbed toml for pkg-2.0.1 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/pkg/2.0.1/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing pkg-2.0.1 against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-0/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/pkg/2.0.1:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] f1fc014220411e2cbd5282387a1899a73005d8190a6d657dbeb12148e0f72c65
[INFO] running `"docker" "start" "-a" "f1fc014220411e2cbd5282387a1899a73005d8190a6d657dbeb12148e0f72c65"`
[INFO] [stderr]    Compiling lazy_static v1.2.0
[INFO] [stderr]    Compiling pkg_impl v2.0.0
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/pkg_impl-2.0.0/src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(proc_macro)]
[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 `pkg_impl`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "f1fc014220411e2cbd5282387a1899a73005d8190a6d657dbeb12148e0f72c65"`
[INFO] running `"docker" "rm" "-f" "f1fc014220411e2cbd5282387a1899a73005d8190a6d657dbeb12148e0f72c65"`
[INFO] [stdout] f1fc014220411e2cbd5282387a1899a73005d8190a6d657dbeb12148e0f72c65