[INFO] crate tectonicdb 0.2.3 is already in cache
[INFO] extracting crate tectonicdb 0.2.3 into work/ex/beta-1.37-6/sources/1.36.0/reg/tectonicdb/0.2.3
[INFO] extracting crate tectonicdb 0.2.3 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/tectonicdb/0.2.3
[INFO] validating manifest of tectonicdb-0.2.3 on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of tectonicdb-0.2.3 on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing tectonicdb-0.2.3
[INFO] finished frobbing tectonicdb-0.2.3
[INFO] frobbed toml for tectonicdb-0.2.3 written to work/ex/beta-1.37-6/sources/1.36.0/reg/tectonicdb/0.2.3/Cargo.toml
[INFO] started frobbing tectonicdb-0.2.3
[INFO] finished frobbing tectonicdb-0.2.3
[INFO] frobbed toml for tectonicdb-0.2.3 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/tectonicdb/0.2.3/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing tectonicdb-0.2.3 against 1.36.0 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-3/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/reg/tectonicdb/0.2.3:/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" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] b031d49627947a45380082d1024efeb49ea704fd3a51ffaaba22375ee1a1b13b
[INFO] running `"docker" "start" "-a" "b031d49627947a45380082d1024efeb49ea704fd3a51ffaaba22375ee1a1b13b"`
[INFO] [stderr]    Compiling circular-queue v0.2.0
[INFO] [stderr]    Compiling term_size v0.3.1
[INFO] [stderr]    Compiling fern v0.5.8
[INFO] [stderr]    Compiling uuid v0.5.1
[INFO] [stderr]    Compiling config v0.6.0
[INFO] [stderr]    Compiling tokio-signal v0.2.7
[INFO] [stderr]    Compiling textwrap v0.8.0
[INFO] [stderr]    Compiling clap v2.26.2
[INFO] [stderr]    Compiling tectonicdb v0.2.3 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/lib/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(libc)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/lib/lib.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![feature(rustc_private)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `tectonicdb`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "b031d49627947a45380082d1024efeb49ea704fd3a51ffaaba22375ee1a1b13b"`
[INFO] running `"docker" "rm" "-f" "b031d49627947a45380082d1024efeb49ea704fd3a51ffaaba22375ee1a1b13b"`
[INFO] [stdout] b031d49627947a45380082d1024efeb49ea704fd3a51ffaaba22375ee1a1b13b