[INFO] crate x86_64 0.7.4 is already in cache
[INFO] extracting crate x86_64 0.7.4 into work/ex/beta-1.38-1/sources/1.37.0/reg/x86_64/0.7.4
[INFO] extracting crate x86_64 0.7.4 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/x86_64/0.7.4
[INFO] validating manifest of x86_64-0.7.4 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 x86_64-0.7.4 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 x86_64-0.7.4
[INFO] finished frobbing x86_64-0.7.4
[INFO] frobbed toml for x86_64-0.7.4 written to work/ex/beta-1.38-1/sources/1.37.0/reg/x86_64/0.7.4/Cargo.toml
[INFO] started frobbing x86_64-0.7.4
[INFO] finished frobbing x86_64-0.7.4
[INFO] frobbed toml for x86_64-0.7.4 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/x86_64/0.7.4/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] 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 x86_64-0.7.4 against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-4/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/x86_64/0.7.4:/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" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] ab86e515b7a13cf99e03119887fafcf54fcca22dd881bea8ed8956066ed76df6
[INFO] running `"docker" "start" "-a" "ab86e515b7a13cf99e03119887fafcf54fcca22dd881bea8ed8956066ed76df6"`
[INFO] [stderr]    Compiling ux v0.1.3
[INFO] [stderr]    Compiling bit_field v0.9.0
[INFO] [stderr]    Compiling x86_64 v0.7.4 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![feature(const_fn)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:5:1
[INFO] [stderr]   |
[INFO] [stderr] 5 | #![feature(asm)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:6:1
[INFO] [stderr]   |
[INFO] [stderr] 6 | #![feature(abi_x86_interrupt)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `x86_64`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "ab86e515b7a13cf99e03119887fafcf54fcca22dd881bea8ed8956066ed76df6"`
[INFO] running `"docker" "rm" "-f" "ab86e515b7a13cf99e03119887fafcf54fcca22dd881bea8ed8956066ed76df6"`
[INFO] [stdout] ab86e515b7a13cf99e03119887fafcf54fcca22dd881bea8ed8956066ed76df6