[INFO] crate arendur 0.0.5 is already in cache
[INFO] extracting crate arendur 0.0.5 into work/ex/beta-1.37-6/sources/1.36.0/reg/arendur/0.0.5
[INFO] extracting crate arendur 0.0.5 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/arendur/0.0.5
[INFO] validating manifest of arendur-0.0.5 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 arendur-0.0.5 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 arendur-0.0.5
[INFO] removed 0 missing examples
[INFO] finished frobbing arendur-0.0.5
[INFO] frobbed toml for arendur-0.0.5 written to work/ex/beta-1.37-6/sources/1.36.0/reg/arendur/0.0.5/Cargo.toml
[INFO] started frobbing arendur-0.0.5
[INFO] removed 0 missing examples
[INFO] finished frobbing arendur-0.0.5
[INFO] frobbed toml for arendur-0.0.5 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/arendur/0.0.5/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 arendur-0.0.5 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-7/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/reg/arendur/0.0.5:/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" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] 649299d0800a7aba605e4fbffa16c9950c14c0eeb21080c7aca553fc06baec98
[INFO] running `"docker" "start" "-a" "649299d0800a7aba605e4fbffa16c9950c14c0eeb21080c7aca553fc06baec98"`
[INFO] [stderr]    Compiling copy_arena v0.1.1
[INFO] [stderr]    Compiling tobj v0.1.8
[INFO] [stderr]    Compiling aren_alloc v0.2.1
[INFO] [stderr]    Compiling gif v0.9.2
[INFO] [stderr]    Compiling num-rational v0.1.42
[INFO] [stderr]    Compiling png v0.6.2
[INFO] [stderr]    Compiling cgmath v0.14.1
[INFO] [stderr]    Compiling rayon v0.7.1
[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/aren_alloc-0.2.1/src/lib.rs:31:1
[INFO] [stderr]    |
[INFO] [stderr] 31 | #![feature(coerce_unsized)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[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/aren_alloc-0.2.1/src/lib.rs:32:1
[INFO] [stderr]    |
[INFO] [stderr] 32 | #![feature(unsize)]
[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 `aren_alloc`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "649299d0800a7aba605e4fbffa16c9950c14c0eeb21080c7aca553fc06baec98"`
[INFO] running `"docker" "rm" "-f" "649299d0800a7aba605e4fbffa16c9950c14c0eeb21080c7aca553fc06baec98"`
[INFO] [stdout] 649299d0800a7aba605e4fbffa16c9950c14c0eeb21080c7aca553fc06baec98