[INFO] fetching crate mech-program 0.0.5...
[INFO] testing mech-program-0.0.5 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate mech-program 0.0.5 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate mech-program 0.0.5 on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "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-7/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-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded backtrace v0.3.41
[INFO] [stderr]   Downloaded serde_json v1.0.52
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "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" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3d6d91052285320f86195753b8413f2438d0f3db82b9a55b4c04f07fed4ea451
[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" "3d6d91052285320f86195753b8413f2438d0f3db82b9a55b4c04f07fed4ea451", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3d6d91052285320f86195753b8413f2438d0f3db82b9a55b4c04f07fed4ea451", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3d6d91052285320f86195753b8413f2438d0f3db82b9a55b4c04f07fed4ea451", kill_on_drop: false }`
[INFO] [stdout] 3d6d91052285320f86195753b8413f2438d0f3db82b9a55b4c04f07fed4ea451
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "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" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 50a05a1eff425592db78aebe48ec858a060070b2bdc35823df8730da92782055
[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" "50a05a1eff425592db78aebe48ec858a060070b2bdc35823df8730da92782055", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.69
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]    Compiling futures v0.1.29
[INFO] [stderr]    Compiling cc v1.0.52
[INFO] [stderr]    Compiling version_check v0.9.1
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling either v1.5.3
[INFO] [stderr]    Compiling smallvec v1.4.0
[INFO] [stderr]    Compiling fnv v1.0.6
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling autocfg v0.1.7
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling openssl v0.10.29
[INFO] [stderr]    Compiling byte-tools v0.3.1
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]    Compiling native-tls v0.2.4
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling openssl-probe v0.1.2
[INFO] [stderr]    Compiling ahash v0.3.4
[INFO] [stderr]    Compiling nodrop v0.1.14
[INFO] [stderr]    Compiling regex-syntax v0.6.17
[INFO] [stderr]    Compiling crc32fast v1.2.0
[INFO] [stderr]    Compiling ppv-lite86 v0.2.6
[INFO] [stderr]    Compiling fake-simd v0.1.2
[INFO] [stderr]    Compiling static_assertions v0.3.4
[INFO] [stderr]    Compiling adler32 v1.0.4
[INFO] [stderr]    Compiling opaque-debug v0.2.3
[INFO] [stderr]    Compiling encoding_rs v0.8.22
[INFO] [stderr]    Compiling libloading v0.6.2
[INFO] [stderr]    Compiling base64 v0.11.0
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]    Compiling try_from v0.3.2
[INFO] [stderr]    Compiling block-padding v0.1.5
[INFO] [stderr]    Compiling unicode-normalization v0.1.12
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]    Compiling http v0.2.1
[INFO] [stderr]    Compiling input_buffer v0.3.1
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling miniz_oxide v0.3.6
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling unicase v2.6.0
[INFO] [stderr]    Compiling error-chain v0.12.2
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]    Compiling base64 v0.10.1
[INFO] [stderr]    Compiling lexical-core v0.6.7
[INFO] [stderr]    Compiling hyper v0.12.35
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling generic-array v0.12.3
[INFO] [stderr]    Compiling tokio-sync v0.1.8
[INFO] [stderr]    Compiling want v0.2.0
[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 idna v0.2.0
[INFO] [stderr]    Compiling idna v0.1.5
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling net2 v0.2.34
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling time v0.1.43
[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]    Compiling rand_os v0.1.3
[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" "50a05a1eff425592db78aebe48ec858a060070b2bdc35823df8730da92782055", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "50a05a1eff425592db78aebe48ec858a060070b2bdc35823df8730da92782055", kill_on_drop: false }`
[INFO] [stdout] 50a05a1eff425592db78aebe48ec858a060070b2bdc35823df8730da92782055