[INFO] fetching crate brack 0.2.0...
[INFO] documenting brack-0.2.0 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate brack 0.2.0 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate brack 0.2.0 on toolchain 1.61.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate brack 0.2.0
[INFO] finished tweaking crates.io crate brack 0.2.0
[INFO] tweaked toml for crates.io crate brack 0.2.0 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate crates.io crate brack 0.2.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "fetch" "--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-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8839515eb22235fc623d0116197273dbfc5877e319041813a78158b8e27411be
[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" "8839515eb22235fc623d0116197273dbfc5877e319041813a78158b8e27411be", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8839515eb22235fc623d0116197273dbfc5877e319041813a78158b8e27411be", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8839515eb22235fc623d0116197273dbfc5877e319041813a78158b8e27411be", kill_on_drop: false }`
[INFO] [stdout] 8839515eb22235fc623d0116197273dbfc5877e319041813a78158b8e27411be
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d190cb871061d98bc6d0581d85cb2ecb09a0f8a142ba5463de30be9999fc3251" "/opt/rustwide/cargo-home/bin/cargo" "+1.61.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--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] 48b26897b4bb52c0bb8cbf49593c989595dd298f9a42c99b4d0cf6f7c87ebd78
[INFO] running `Command { std: "docker" "start" "-a" "48b26897b4bb52c0bb8cbf49593c989595dd298f9a42c99b4d0cf6f7c87ebd78", kill_on_drop: false }`
[INFO] [stderr]    Compiling anyhow v1.0.41
[INFO] [stderr]  Documenting brack v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(assert_matches)]
[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 document `brack`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name brack src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=a350401261f1c4eb -L dependency=/opt/rustwide/target/debug/deps --extern anyhow=/opt/rustwide/target/debug/deps/libanyhow-d04bc6234597c37f.rmeta --extern glob=/opt/rustwide/target/debug/deps/libglob-ad7a2bc260eeb594.rmeta --cap-lints=warn --crate-version 0.2.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "48b26897b4bb52c0bb8cbf49593c989595dd298f9a42c99b4d0cf6f7c87ebd78", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "48b26897b4bb52c0bb8cbf49593c989595dd298f9a42c99b4d0cf6f7c87ebd78", kill_on_drop: false }`
[INFO] [stdout] 48b26897b4bb52c0bb8cbf49593c989595dd298f9a42c99b4d0cf6f7c87ebd78