[INFO] crate mech 0.0.5 is already in cache
[INFO] testing mech-0.0.5 against beta-2020-07-24 for beta-1.46-1
[INFO] extracting crate mech 0.0.5 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate mech 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 0.0.5
[INFO] finished tweaking crates.io crate mech 0.0.5
[INFO] tweaked toml for crates.io crate mech 0.0.5 written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate crates.io crate mech 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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] fa16a4a717b0db83865b64ca106123e0d33e683b250dc9af9bfc4184a9469b0f
[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" "fa16a4a717b0db83865b64ca106123e0d33e683b250dc9af9bfc4184a9469b0f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "fa16a4a717b0db83865b64ca106123e0d33e683b250dc9af9bfc4184a9469b0f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fa16a4a717b0db83865b64ca106123e0d33e683b250dc9af9bfc4184a9469b0f", kill_on_drop: false }`
[INFO] [stdout] fa16a4a717b0db83865b64ca106123e0d33e683b250dc9af9bfc4184a9469b0f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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] e0c1db0c0737b8eece630716f1ec3feed337874f5852084a560cfb9e1d6f7302
[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" "e0c1db0c0737b8eece630716f1ec3feed337874f5852084a560cfb9e1d6f7302", kill_on_drop: false }`
[INFO] [stderr]    Compiling arc-swap v0.4.6
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling copyless v0.1.4
[INFO] [stderr]    Compiling once_cell v1.3.1
[INFO] [stderr]    Compiling ahash v0.3.4
[INFO] [stderr]    Compiling v_htmlescape v0.4.5
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]    Compiling brotli-sys v0.3.2
[INFO] [stderr]    Compiling ring v0.16.13
[INFO] [stderr]    Compiling bytestring v0.1.5
[INFO] [stderr]    Compiling input_buffer v0.3.1
[INFO] [stderr]    Compiling nom v5.1.1
[INFO] [stderr]    Compiling openssl-sys v0.9.55
[INFO] [stderr]    Compiling nom v4.2.3
[INFO] [stderr]    Compiling net2 v0.2.34
[INFO] [stderr]    Compiling hostname v0.3.1
[INFO] [stderr]    Compiling lexical-core v0.6.2
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling threadpool v1.8.0
[INFO] [stderr]    Compiling colored v1.9.3
[INFO] [stderr]    Compiling clap v2.33.0
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling resolv-conf v0.6.3
[INFO] [stderr]    Compiling mio v0.6.22
[INFO] [stderr]    Compiling chrono v0.4.11
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling signal-hook-registry v1.2.0
[INFO] [stderr]    Compiling publicsuffix v1.5.4
[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 tokio-threadpool v0.1.18
[INFO] [stderr]    Compiling tokio-io v0.1.13
[INFO] [stderr]    Compiling http v0.1.21
[INFO] [stderr]    Compiling tokio-buf v0.1.1
[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" "e0c1db0c0737b8eece630716f1ec3feed337874f5852084a560cfb9e1d6f7302", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e0c1db0c0737b8eece630716f1ec3feed337874f5852084a560cfb9e1d6f7302", kill_on_drop: false }`
[INFO] [stdout] e0c1db0c0737b8eece630716f1ec3feed337874f5852084a560cfb9e1d6f7302