[INFO] fetching crate niobium 0.0.0...
[INFO] testing niobium-0.0.0 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate niobium 0.0.0 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate niobium 0.0.0 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 niobium 0.0.0
[INFO] finished tweaking crates.io crate niobium 0.0.0
[INFO] tweaked toml for crates.io crate niobium 0.0.0 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate crates.io crate niobium 0.0.0 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7ec763cebc93c9658270fe8f0e73b0205801a7f2e319241fc40ea825eadaecaa
[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" "7ec763cebc93c9658270fe8f0e73b0205801a7f2e319241fc40ea825eadaecaa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7ec763cebc93c9658270fe8f0e73b0205801a7f2e319241fc40ea825eadaecaa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7ec763cebc93c9658270fe8f0e73b0205801a7f2e319241fc40ea825eadaecaa", kill_on_drop: false }`
[INFO] [stdout] 7ec763cebc93c9658270fe8f0e73b0205801a7f2e319241fc40ea825eadaecaa
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 922f7357632a9c3c99d4ffbdf0538a89df1557d22b897f554148f47d7f0c12a5
[INFO] running `Command { std: "docker" "start" "-a" "922f7357632a9c3c99d4ffbdf0538a89df1557d22b897f554148f47d7f0c12a5", kill_on_drop: false }`
[INFO] [stderr]    Compiling niobium v0.0.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.35s
[INFO] running `Command { std: "docker" "inspect" "922f7357632a9c3c99d4ffbdf0538a89df1557d22b897f554148f47d7f0c12a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "922f7357632a9c3c99d4ffbdf0538a89df1557d22b897f554148f47d7f0c12a5", kill_on_drop: false }`
[INFO] [stdout] 922f7357632a9c3c99d4ffbdf0538a89df1557d22b897f554148f47d7f0c12a5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 52fa46d9aab9292286f09d56599493b2cdc10d621ccf98b95607be158d5ba91e
[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" "52fa46d9aab9292286f09d56599493b2cdc10d621ccf98b95607be158d5ba91e", kill_on_drop: false }`
[INFO] [stderr]    Compiling niobium v0.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> examples/hello_magic.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(start)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: language item required, but not found: `eh_personality`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `niobium`
[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" "52fa46d9aab9292286f09d56599493b2cdc10d621ccf98b95607be158d5ba91e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "52fa46d9aab9292286f09d56599493b2cdc10d621ccf98b95607be158d5ba91e", kill_on_drop: false }`
[INFO] [stdout] 52fa46d9aab9292286f09d56599493b2cdc10d621ccf98b95607be158d5ba91e