[INFO] fetching crate mlsag 0.3.0...
[INFO] testing mlsag-0.3.0 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate mlsag 0.3.0 into /workspace/builds/worker-13/source
[INFO] validating manifest of crates.io crate mlsag 0.3.0 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 mlsag 0.3.0
[INFO] finished tweaking crates.io crate mlsag 0.3.0
[INFO] tweaked toml for crates.io crate mlsag 0.3.0 written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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] defb755c6beae2279d8be6881e868f3399d3ecea5ae65f8b9adc4e0c3d29e343
[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" "defb755c6beae2279d8be6881e868f3399d3ecea5ae65f8b9adc4e0c3d29e343", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "defb755c6beae2279d8be6881e868f3399d3ecea5ae65f8b9adc4e0c3d29e343", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "defb755c6beae2279d8be6881e868f3399d3ecea5ae65f8b9adc4e0c3d29e343", kill_on_drop: false }`
[INFO] [stdout] defb755c6beae2279d8be6881e868f3399d3ecea5ae65f8b9adc4e0c3d29e343
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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] 672893e14292981da049861079a1f09413d1fa03dedd18f7c1ea97f17e477eb4
[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" "672893e14292981da049861079a1f09413d1fa03dedd18f7c1ea97f17e477eb4", kill_on_drop: false }`
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling subtle v2.4.0
[INFO] [stderr]    Compiling keccak v0.1.0
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling clear_on_drop v0.2.4
[INFO] [stderr]    Compiling zeroize_derive v1.0.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[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/subtle-2.4.0/src/lib.rs:12:34
[INFO] [stdout]    |
[INFO] [stdout] 12 | #![cfg_attr(feature = "nightly", feature(external_doc))]
[INFO] [stdout]    |                                  ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[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 `subtle`
[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" "672893e14292981da049861079a1f09413d1fa03dedd18f7c1ea97f17e477eb4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "672893e14292981da049861079a1f09413d1fa03dedd18f7c1ea97f17e477eb4", kill_on_drop: false }`
[INFO] [stdout] 672893e14292981da049861079a1f09413d1fa03dedd18f7c1ea97f17e477eb4