[INFO] fetching crate jn 0.1.0...
[INFO] documenting jn-0.1.0 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate jn 0.1.0 into /workspace/builds/worker-14/source
[INFO] validating manifest of crates.io crate jn 0.1.0 on toolchain 1.46.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate jn 0.1.0
[INFO] finished tweaking crates.io crate jn 0.1.0
[INFO] tweaked toml for crates.io crate jn 0.1.0 written to /workspace/builds/worker-14/source/Cargo.toml
[INFO] crate crates.io crate jn 0.1.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5c4a3de4007f38352946c3ee7b9defc3b5df92517f4ec114eaf4060e1f59da16
[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" "5c4a3de4007f38352946c3ee7b9defc3b5df92517f4ec114eaf4060e1f59da16", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5c4a3de4007f38352946c3ee7b9defc3b5df92517f4ec114eaf4060e1f59da16", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5c4a3de4007f38352946c3ee7b9defc3b5df92517f4ec114eaf4060e1f59da16", kill_on_drop: false }`
[INFO] [stdout] 5c4a3de4007f38352946c3ee7b9defc3b5df92517f4ec114eaf4060e1f59da16
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "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] a09cd8fcf32a52a0e33beff0116be3a2eb73660efbae13f54deae48cf4e08c3c
[INFO] running `Command { std: "docker" "start" "-a" "a09cd8fcf32a52a0e33beff0116be3a2eb73660efbae13f54deae48cf4e08c3c", kill_on_drop: false }`
[INFO] [stderr]     Checking dirs-sys v0.3.4
[INFO] [stderr]     Checking hostname v0.3.0
[INFO] [stderr]     Checking serde v1.0.104
[INFO] [stderr]     Checking dirs v2.0.2
[INFO] [stderr]     Checking serde_json v1.0.48
[INFO] [stderr]     Checking chrono v0.4.10
[INFO] [stderr]  Documenting jn v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(map_first_last)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[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 document `jn`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name jn src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern chrono=/opt/rustwide/target/debug/deps/libchrono-f7871200be29030e.rmeta --extern clap=/opt/rustwide/target/debug/deps/libclap-75ea384b1f7f2595.rmeta --extern dirs=/opt/rustwide/target/debug/deps/libdirs-05d656eaec448d28.rmeta --extern hostname=/opt/rustwide/target/debug/deps/libhostname-7721d9b0d0e76256.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-e96c571c97517ae0.rmeta --extern serde_json=/opt/rustwide/target/debug/deps/libserde_json-4df0aebb9aea9c5c.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "a09cd8fcf32a52a0e33beff0116be3a2eb73660efbae13f54deae48cf4e08c3c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a09cd8fcf32a52a0e33beff0116be3a2eb73660efbae13f54deae48cf4e08c3c", kill_on_drop: false }`
[INFO] [stdout] a09cd8fcf32a52a0e33beff0116be3a2eb73660efbae13f54deae48cf4e08c3c