[INFO] crate punkt 1.0.5 is already in cache
[INFO] extracting crate punkt 1.0.5 into work/ex/beta-1.38-1/sources/1.37.0/reg/punkt/1.0.5
[INFO] extracting crate punkt 1.0.5 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/punkt/1.0.5
[INFO] validating manifest of punkt-1.0.5 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 punkt-1.0.5 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 punkt-1.0.5
[INFO] finished frobbing punkt-1.0.5
[INFO] frobbed toml for punkt-1.0.5 written to work/ex/beta-1.38-1/sources/1.37.0/reg/punkt/1.0.5/Cargo.toml
[INFO] started frobbing punkt-1.0.5
[INFO] finished frobbing punkt-1.0.5
[INFO] frobbed toml for punkt-1.0.5 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/punkt/1.0.5/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 punkt-1.0.5 against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/punkt/1.0.5:/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 4fab12a819baabd0ee5c9d2067199dde8cfdd961d6c74a8d33b235bd024a61a4
[INFO] running `"docker" "start" "-a" "4fab12a819baabd0ee5c9d2067199dde8cfdd961d6c74a8d33b235bd024a61a4"`
[INFO] [stderr]    Compiling rust-freqdist v0.1.5
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling phf_macros v0.7.24
[INFO] [stderr]    Compiling phf v0.7.24
[INFO] [stderr]    Compiling punkt v1.0.5 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]    --> src/lib.rs:141:1
[INFO] [stderr]     |
[INFO] [stderr] 141 | #![feature(proc_macro_hygiene)]
[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 `punkt`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "4fab12a819baabd0ee5c9d2067199dde8cfdd961d6c74a8d33b235bd024a61a4"`
[INFO] running `"docker" "rm" "-f" "4fab12a819baabd0ee5c9d2067199dde8cfdd961d6c74a8d33b235bd024a61a4"`
[INFO] [stdout] 4fab12a819baabd0ee5c9d2067199dde8cfdd961d6c74a8d33b235bd024a61a4