[INFO] crate compact 0.2.15 is already in cache
[INFO] extracting crate compact 0.2.15 into work/ex/beta-1.38-1/sources/1.37.0/reg/compact/0.2.15
[INFO] extracting crate compact 0.2.15 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/compact/0.2.15
[INFO] validating manifest of compact-0.2.15 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 compact-0.2.15 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 compact-0.2.15
[INFO] finished frobbing compact-0.2.15
[INFO] frobbed toml for compact-0.2.15 written to work/ex/beta-1.38-1/sources/1.37.0/reg/compact/0.2.15/Cargo.toml
[INFO] started frobbing compact-0.2.15
[INFO] finished frobbing compact-0.2.15
[INFO] frobbed toml for compact-0.2.15 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/compact/0.2.15/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 compact-0.2.15 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-3/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/compact/0.2.15:/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] cb8f35273eef9b190bd1a9375aa11a4fa3a08b334dfdcefcacde6ce7b15ccdd3
[INFO] running `"docker" "start" "-a" "cb8f35273eef9b190bd1a9375aa11a4fa3a08b334dfdcefcacde6ce7b15ccdd3"`
[INFO] [stderr]    Compiling simple_allocator_trait v0.1.0
[INFO] [stderr]    Compiling num-integer v0.1.41
[INFO] [stderr]    Compiling primal-check v0.2.3
[INFO] [stderr]    Compiling primal v0.2.3
[INFO] [stderr]    Compiling compact v0.2.15 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]   --> src/lib.rs:17:1
[INFO] [stderr]    |
[INFO] [stderr] 17 | #![feature(specialization)]
[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 `compact`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "cb8f35273eef9b190bd1a9375aa11a4fa3a08b334dfdcefcacde6ce7b15ccdd3"`
[INFO] running `"docker" "rm" "-f" "cb8f35273eef9b190bd1a9375aa11a4fa3a08b334dfdcefcacde6ce7b15ccdd3"`
[INFO] [stdout] cb8f35273eef9b190bd1a9375aa11a4fa3a08b334dfdcefcacde6ce7b15ccdd3