[INFO] crate autoperf 0.9.4 is already in cache
[INFO] extracting crate autoperf 0.9.4 into work/ex/beta-1.38-1/sources/1.37.0/reg/autoperf/0.9.4
[INFO] extracting crate autoperf 0.9.4 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/autoperf/0.9.4
[INFO] validating manifest of autoperf-0.9.4 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 autoperf-0.9.4 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 autoperf-0.9.4
[INFO] finished frobbing autoperf-0.9.4
[INFO] frobbed toml for autoperf-0.9.4 written to work/ex/beta-1.38-1/sources/1.37.0/reg/autoperf/0.9.4/Cargo.toml
[INFO] started frobbing autoperf-0.9.4
[INFO] finished frobbing autoperf-0.9.4
[INFO] frobbed toml for autoperf-0.9.4 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/autoperf/0.9.4/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] [stderr]     Blocking waiting for file lock on package cache
[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] [stderr]     Blocking waiting for file lock on package cache
[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 autoperf-0.9.4 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-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/autoperf/0.9.4:/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] fb14bb7c374aed67ac32601f4d795101de17f3d7412487b1c6b57f1ad2e00360
[INFO] running `"docker" "start" "-a" "fb14bb7c374aed67ac32601f4d795101de17f3d7412487b1c6b57f1ad2e00360"`
[INFO] [stderr]    Compiling phf_shared v0.7.24
[INFO] [stderr]    Compiling itertools v0.5.10
[INFO] [stderr]    Compiling wait-timeout v0.1.5
[INFO] [stderr]    Compiling mmap v0.1.1
[INFO] [stderr]    Compiling num-rational v0.1.42
[INFO] [stderr]    Compiling env_logger v0.6.2
[INFO] [stderr]    Compiling phf_generator v0.7.24
[INFO] [stderr]    Compiling phf v0.7.24
[INFO] [stderr]    Compiling phf_codegen v0.7.24
[INFO] [stderr]    Compiling num v0.1.42
[INFO] [stderr]    Compiling serde v0.6.15
[INFO] [stderr]    Compiling serde_json v0.6.1
[INFO] [stderr]    Compiling x86 v0.16.3
[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/x86-0.16.3/src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(const_fn, asm, repr_transparent)]
[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 `x86`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "fb14bb7c374aed67ac32601f4d795101de17f3d7412487b1c6b57f1ad2e00360"`
[INFO] running `"docker" "rm" "-f" "fb14bb7c374aed67ac32601f4d795101de17f3d7412487b1c6b57f1ad2e00360"`
[INFO] [stdout] fb14bb7c374aed67ac32601f4d795101de17f3d7412487b1c6b57f1ad2e00360