[INFO] fetching crate rlibcex 0.1.2...
[INFO] testing rlibcex-0.1.2 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate rlibcex 0.1.2 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate rlibcex 0.1.2 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 rlibcex 0.1.2
[INFO] finished tweaking crates.io crate rlibcex 0.1.2
[INFO] tweaked toml for crates.io crate rlibcex 0.1.2 written to /workspace/builds/worker-0/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] 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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", 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] 27836a582e2b14aef6374eaf2d7c67425bdfc338ba5082a634dc62dad3732653
[INFO] running `Command { std: "docker" "start" "-a" "27836a582e2b14aef6374eaf2d7c67425bdfc338ba5082a634dc62dad3732653", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "27836a582e2b14aef6374eaf2d7c67425bdfc338ba5082a634dc62dad3732653", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "27836a582e2b14aef6374eaf2d7c67425bdfc338ba5082a634dc62dad3732653", kill_on_drop: false }`
[INFO] [stdout] 27836a582e2b14aef6374eaf2d7c67425bdfc338ba5082a634dc62dad3732653
[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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/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] 612316dc003761364c97cafec4e11daa08e46a39c97a139bcaf60b5e8b24e25a
[INFO] running `Command { std: "docker" "start" "-a" "612316dc003761364c97cafec4e11daa08e46a39c97a139bcaf60b5e8b24e25a", kill_on_drop: false }`
[INFO] [stderr]    Compiling rlibcex v0.1.2 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.53s
[INFO] running `Command { std: "docker" "inspect" "612316dc003761364c97cafec4e11daa08e46a39c97a139bcaf60b5e8b24e25a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "612316dc003761364c97cafec4e11daa08e46a39c97a139bcaf60b5e8b24e25a", kill_on_drop: false }`
[INFO] [stdout] 612316dc003761364c97cafec4e11daa08e46a39c97a139bcaf60b5e8b24e25a
[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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 04f1f958fda994df8506ab798cbdf3445b18fb160133b508d9f535451c0f1fd7
[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" "04f1f958fda994df8506ab798cbdf3445b18fb160133b508d9f535451c0f1fd7", kill_on_drop: false }`
[INFO] [stderr]    Compiling rlibcex v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:3:19
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![cfg_attr(test, feature(test))]
[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 `rlibcex`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "04f1f958fda994df8506ab798cbdf3445b18fb160133b508d9f535451c0f1fd7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "04f1f958fda994df8506ab798cbdf3445b18fb160133b508d9f535451c0f1fd7", kill_on_drop: false }`
[INFO] [stdout] 04f1f958fda994df8506ab798cbdf3445b18fb160133b508d9f535451c0f1fd7