[INFO] crate exar 0.1.0 is already in cache
[INFO] extracting crate exar 0.1.0 into work/ex/beta-1.38-1/sources/1.37.0/reg/exar/0.1.0
[INFO] extracting crate exar 0.1.0 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/exar/0.1.0
[INFO] validating manifest of exar-0.1.0 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 exar-0.1.0 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 exar-0.1.0
[INFO] removed path dependency exar-testkit from exar-0.1.0
[INFO] finished frobbing exar-0.1.0
[INFO] frobbed toml for exar-0.1.0 written to work/ex/beta-1.38-1/sources/1.37.0/reg/exar/0.1.0/Cargo.toml
[INFO] started frobbing exar-0.1.0
[INFO] removed path dependency exar-testkit from exar-0.1.0
[INFO] finished frobbing exar-0.1.0
[INFO] frobbed toml for exar-0.1.0 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/exar/0.1.0/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 exar-0.1.0 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/exar/0.1.0:/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] 241e70d0c687f996d17eb883159ac31d827e5713938cd216faeb0598d578cd12
[INFO] running `"docker" "start" "-a" "241e70d0c687f996d17eb883159ac31d827e5713938cd216faeb0598d578cd12"`
[INFO] [stderr]    Compiling exar v0.1.0 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.97s
[INFO] running `"docker" "inspect" "241e70d0c687f996d17eb883159ac31d827e5713938cd216faeb0598d578cd12"`
[INFO] running `"docker" "rm" "-f" "241e70d0c687f996d17eb883159ac31d827e5713938cd216faeb0598d578cd12"`
[INFO] [stdout] 241e70d0c687f996d17eb883159ac31d827e5713938cd216faeb0598d578cd12
[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/exar/0.1.0:/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" "test" "--frozen" "--no-run"`
[INFO] [stdout] f465068e7171be6c44cb5749f0710095bdb2c5753e1db8656794f02234978732
[INFO] running `"docker" "start" "-a" "f465068e7171be6c44cb5749f0710095bdb2c5753e1db8656794f02234978732"`
[INFO] [stderr]    Compiling serde v0.7.15
[INFO] [stderr]    Compiling exar-testkit v0.1.0
[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/exar-testkit-0.1.0/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(const_fn)]
[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 `exar-testkit`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "f465068e7171be6c44cb5749f0710095bdb2c5753e1db8656794f02234978732"`
[INFO] running `"docker" "rm" "-f" "f465068e7171be6c44cb5749f0710095bdb2c5753e1db8656794f02234978732"`
[INFO] [stdout] f465068e7171be6c44cb5749f0710095bdb2c5753e1db8656794f02234978732