[INFO] updating cached repository eochat/client
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/eochat/client
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/eochat/client" "work/ex/beta-1.38-1/sources/1.37.0/gh/eochat/client"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/eochat/client'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/eochat/client" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/eochat/client"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/eochat/client'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 0f9769a43bfba1cb8c4890ce487fec2d3a22297e
[INFO] sha for GitHub repo eochat/client: 0f9769a43bfba1cb8c4890ce487fec2d3a22297e
[INFO] validating manifest of eochat/client 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 eochat/client 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 eochat/client
[INFO] finished frobbing eochat/client
[INFO] frobbed toml for eochat/client written to work/ex/beta-1.38-1/sources/1.37.0/gh/eochat/client/Cargo.toml
[INFO] started frobbing eochat/client
[INFO] finished frobbing eochat/client
[INFO] frobbed toml for eochat/client written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/eochat/client/Cargo.toml
[INFO] crate eochat/client already has a lockfile, it will not be regenerated
[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 eochat/client 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-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/eochat/client:/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] 9b7f96b4e72bc3f2c583bb9a9d7c936e9102a33ea9d0c9d8b4a5a1f97e163fd3
[INFO] running `"docker" "start" "-a" "9b7f96b4e72bc3f2c583bb9a9d7c936e9102a33ea9d0c9d8b4a5a1f97e163fd3"`
[INFO] [stderr]    Compiling quote v0.3.10
[INFO] [stderr]    Compiling unicode-xid v0.0.3
[INFO] [stderr]    Compiling serde v0.8.19
[INFO] [stderr]    Compiling syn v0.10.3
[INFO] [stderr]    Compiling serde_codegen_internals v0.11.1
[INFO] [stderr]    Compiling serde_codegen v0.8.19
[INFO] [stderr]    Compiling serde_json v0.8.4
[INFO] [stderr]    Compiling serde_derive v0.8.19
[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/serde_derive-0.8.19/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(proc_macro, proc_macro_lib)]
[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 `serde_derive`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "9b7f96b4e72bc3f2c583bb9a9d7c936e9102a33ea9d0c9d8b4a5a1f97e163fd3"`
[INFO] running `"docker" "rm" "-f" "9b7f96b4e72bc3f2c583bb9a9d7c936e9102a33ea9d0c9d8b4a5a1f97e163fd3"`
[INFO] [stdout] 9b7f96b4e72bc3f2c583bb9a9d7c936e9102a33ea9d0c9d8b4a5a1f97e163fd3