[INFO] crate cargo_meta 0.1.4 is already in cache
[INFO] extracting crate cargo_meta 0.1.4 into work/ex/beta-1.38-1/sources/1.37.0/reg/cargo_meta/0.1.4
[INFO] extracting crate cargo_meta 0.1.4 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/cargo_meta/0.1.4
[INFO] validating manifest of cargo_meta-0.1.4 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 cargo_meta-0.1.4 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 cargo_meta-0.1.4
[INFO] finished frobbing cargo_meta-0.1.4
[INFO] frobbed toml for cargo_meta-0.1.4 written to work/ex/beta-1.38-1/sources/1.37.0/reg/cargo_meta/0.1.4/Cargo.toml
[INFO] started frobbing cargo_meta-0.1.4
[INFO] finished frobbing cargo_meta-0.1.4
[INFO] frobbed toml for cargo_meta-0.1.4 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/cargo_meta/0.1.4/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] [stderr]     Blocking waiting for file lock on package cache
[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 cargo_meta-0.1.4 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-1/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/cargo_meta/0.1.4:/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] ef2fc4b61c4d38803e67e7ff0242dda325ee06f3ee24a7d1e81605cc2982cd93
[INFO] running `"docker" "start" "-a" "ef2fc4b61c4d38803e67e7ff0242dda325ee06f3ee24a7d1e81605cc2982cd93"`
[INFO] [stderr]    Compiling cargo_meta_proc v0.1.4
[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/cargo_meta_proc-0.1.4/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(proc_macro_diagnostic)]
[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 `cargo_meta_proc`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "ef2fc4b61c4d38803e67e7ff0242dda325ee06f3ee24a7d1e81605cc2982cd93"`
[INFO] running `"docker" "rm" "-f" "ef2fc4b61c4d38803e67e7ff0242dda325ee06f3ee24a7d1e81605cc2982cd93"`
[INFO] [stdout] ef2fc4b61c4d38803e67e7ff0242dda325ee06f3ee24a7d1e81605cc2982cd93