[INFO] crate mech-program 0.0.5 is already in cache
[INFO] testing mech-program-0.0.5 against beta-2020-07-24 for beta-1.46-1
[INFO] extracting crate mech-program 0.0.5 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate mech-program 0.0.5 on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate mech-program 0.0.5
[INFO] finished tweaking crates.io crate mech-program 0.0.5
[INFO] tweaked toml for crates.io crate mech-program 0.0.5 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] crate crates.io crate mech-program 0.0.5 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 127c5f4b6221e11c5c4180c4dbbc0d81546f99266ef160307054a7e903ebd8b6
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "127c5f4b6221e11c5c4180c4dbbc0d81546f99266ef160307054a7e903ebd8b6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "127c5f4b6221e11c5c4180c4dbbc0d81546f99266ef160307054a7e903ebd8b6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "127c5f4b6221e11c5c4180c4dbbc0d81546f99266ef160307054a7e903ebd8b6", kill_on_drop: false }`
[INFO] [stdout] 127c5f4b6221e11c5c4180c4dbbc0d81546f99266ef160307054a7e903ebd8b6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bddb49bb08f16ff685c66200fa33ed1b0e3afbb6feb9039eb2688aadc944daf2
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "bddb49bb08f16ff685c66200fa33ed1b0e3afbb6feb9039eb2688aadc944daf2", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]    Compiling ahash v0.3.4
[INFO] [stderr]    Compiling static_assertions v0.3.4
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]    Compiling backtrace-sys v0.1.37
[INFO] [stderr]    Compiling regex v1.3.7
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]    Compiling idna v0.1.5
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling net2 v0.2.34
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling lexical-core v0.6.7
[INFO] [stderr]    Compiling flate2 v1.0.14
[INFO] [stderr]    Compiling futures-cpupool v0.1.8
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling colored v1.9.3
[INFO] [stderr]    Compiling openssl v0.10.29
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling want v0.2.0
[INFO] [stderr]    Compiling tokio-executor v0.1.10
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]    Compiling crossbeam-queue v0.2.1
[INFO] [stderr]    Compiling crossbeam-channel v0.4.2
[INFO] [stderr]    Compiling mio v0.6.22
[INFO] [stderr]    Compiling uuid v0.7.4
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling quote v1.0.4
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/hashbrown-0.7.2/src/lib.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 15 | /     feature(
[INFO] [stdout] 16 | |         alloc_layout_extra,
[INFO] [stdout] 17 | |         allocator_api,
[INFO] [stdout] 18 | |         ptr_offset_from,
[INFO] [stdout] ...  |
[INFO] [stdout] 22 | |         specialization,
[INFO] [stdout] 23 | |     )
[INFO] [stdout]    | |_____^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling rand_chacha v0.2.2
[INFO] [stderr]    Compiling tokio-current-thread v0.1.7
[INFO] [stderr]    Compiling tokio-timer v0.2.13
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `hashbrown`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "bddb49bb08f16ff685c66200fa33ed1b0e3afbb6feb9039eb2688aadc944daf2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bddb49bb08f16ff685c66200fa33ed1b0e3afbb6feb9039eb2688aadc944daf2", kill_on_drop: false }`
[INFO] [stdout] bddb49bb08f16ff685c66200fa33ed1b0e3afbb6feb9039eb2688aadc944daf2