[INFO] fetching crate redoxfs 0.3.6...
[INFO] extracting crate redoxfs 0.3.6 into work/ex/beta-1.37-6/sources/1.36.0/reg/redoxfs/0.3.6
[INFO] extracting crate redoxfs 0.3.6 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/redoxfs/0.3.6
[INFO] validating manifest of redoxfs-0.3.6 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 redoxfs-0.3.6 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 redoxfs-0.3.6
[INFO] finished frobbing redoxfs-0.3.6
[INFO] frobbed toml for redoxfs-0.3.6 written to work/ex/beta-1.37-6/sources/1.36.0/reg/redoxfs/0.3.6/Cargo.toml
[INFO] started frobbing redoxfs-0.3.6
[INFO] finished frobbing redoxfs-0.3.6
[INFO] frobbed toml for redoxfs-0.3.6 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/redoxfs/0.3.6/Cargo.toml
[INFO] crate redoxfs-0.3.6 already has a lockfile, it will not be regenerated
[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 redoxfs-0.3.6 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-6/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/reg/redoxfs/0.3.6:/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] 9942ceb2a8d3d906a01b91da829be66c4753de324f84df2a8d3124bd5cc6a0b8
[INFO] running `"docker" "start" "-a" "9942ceb2a8d3d906a01b91da829be66c4753de324f84df2a8d3124bd5cc6a0b8"`
[INFO] [stderr]    Compiling libc v0.2.58
[INFO] [stderr]    Compiling pkg-config v0.3.14
[INFO] [stderr]    Compiling thread-scoped v1.0.2
[INFO] [stderr]    Compiling redox_syscall v0.1.56
[INFO] [stderr]    Compiling log v0.4.6
[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/redox_syscall-0.1.56/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(asm)]
[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/redox_syscall-0.1.56/src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(const_fn)]
[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 `redox_syscall`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "9942ceb2a8d3d906a01b91da829be66c4753de324f84df2a8d3124bd5cc6a0b8"`
[INFO] running `"docker" "rm" "-f" "9942ceb2a8d3d906a01b91da829be66c4753de324f84df2a8d3124bd5cc6a0b8"`
[INFO] [stdout] 9942ceb2a8d3d906a01b91da829be66c4753de324f84df2a8d3124bd5cc6a0b8