[INFO] crate exar-client 0.1.0 is already in cache
[INFO] extracting crate exar-client 0.1.0 into work/ex/beta-1.38-1/sources/1.37.0/reg/exar-client/0.1.0
[INFO] extracting crate exar-client 0.1.0 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/exar-client/0.1.0
[INFO] validating manifest of exar-client-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-client-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-client-0.1.0
[INFO] removed path dependency exar from exar-client-0.1.0
[INFO] removed path dependency exar-net from exar-client-0.1.0
[INFO] removed path dependency exar-testkit from exar-client-0.1.0
[INFO] finished frobbing exar-client-0.1.0
[INFO] frobbed toml for exar-client-0.1.0 written to work/ex/beta-1.38-1/sources/1.37.0/reg/exar-client/0.1.0/Cargo.toml
[INFO] started frobbing exar-client-0.1.0
[INFO] removed path dependency exar from exar-client-0.1.0
[INFO] removed path dependency exar-net from exar-client-0.1.0
[INFO] removed path dependency exar-testkit from exar-client-0.1.0
[INFO] finished frobbing exar-client-0.1.0
[INFO] frobbed toml for exar-client-0.1.0 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/exar-client/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-client-0.1.0 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-7/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/exar-client/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 99991341a46dd7b52f91c3fd8ae398930f74c9843a13c0fa2dbecc44cf365931
[INFO] running `"docker" "start" "-a" "99991341a46dd7b52f91c3fd8ae398930f74c9843a13c0fa2dbecc44cf365931"`
[INFO] [stderr]    Compiling exar-net v0.1.0
[INFO] [stderr]    Compiling exar-client v0.1.0 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.51s
[INFO] running `"docker" "inspect" "99991341a46dd7b52f91c3fd8ae398930f74c9843a13c0fa2dbecc44cf365931"`
[INFO] running `"docker" "rm" "-f" "99991341a46dd7b52f91c3fd8ae398930f74c9843a13c0fa2dbecc44cf365931"`
[INFO] [stdout] 99991341a46dd7b52f91c3fd8ae398930f74c9843a13c0fa2dbecc44cf365931
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-7/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/exar-client/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" "+1.37.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] 31fd0420629065bec714f0855166419b09957aa6c2e2db6d92148af74ee620a5
[INFO] running `"docker" "start" "-a" "31fd0420629065bec714f0855166419b09957aa6c2e2db6d92148af74ee620a5"`
[INFO] [stderr]    Compiling exar-testkit v0.1.0
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable 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] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "31fd0420629065bec714f0855166419b09957aa6c2e2db6d92148af74ee620a5"`
[INFO] running `"docker" "rm" "-f" "31fd0420629065bec714f0855166419b09957aa6c2e2db6d92148af74ee620a5"`
[INFO] [stdout] 31fd0420629065bec714f0855166419b09957aa6c2e2db6d92148af74ee620a5