[INFO] cloning repository https://github.com/JosephFerano/rust_os
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/JosephFerano/rust_os" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJosephFerano%2Frust_os", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJosephFerano%2Frust_os'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0502adec20e78e6019d68a023520c0c30f3fcff8
[INFO] documenting JosephFerano/rust_os against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FJosephFerano%2Frust_os" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/JosephFerano/rust_os on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/JosephFerano/rust_os
[INFO] finished tweaking git repo https://github.com/JosephFerano/rust_os
[INFO] tweaked toml for git repo https://github.com/JosephFerano/rust_os written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/JosephFerano/rust_os already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded volatile v0.2.4
[INFO] [stderr]   Downloaded multiboot2 v0.7.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "+beta-2020-08-29" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a6cf1869d583e684adab176eee7a2bfe27630fa4fccab09c2d2916c453e4af99
[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" "a6cf1869d583e684adab176eee7a2bfe27630fa4fccab09c2d2916c453e4af99", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a6cf1869d583e684adab176eee7a2bfe27630fa4fccab09c2d2916c453e4af99", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a6cf1869d583e684adab176eee7a2bfe27630fa4fccab09c2d2916c453e4af99", kill_on_drop: false }`
[INFO] [stdout] a6cf1869d583e684adab176eee7a2bfe27630fa4fccab09c2d2916c453e4af99
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] fbd527fb8e3a741ebd09a3726ba171d6067ddaebdd5f5d8afc2430ca1de934c7
[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" "fbd527fb8e3a741ebd09a3726ba171d6067ddaebdd5f5d8afc2430ca1de934c7", kill_on_drop: false }`
[INFO] [stderr]     Checking bitflags v1.0.4
[INFO] [stderr]     Checking volatile v0.2.4
[INFO] [stderr]     Checking multiboot2 v0.7.1
[INFO] [stderr]  Documenting first_os v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(lang_items)]
[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 `first_os`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type staticlib --crate-name first_os src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern multiboot2=/opt/rustwide/target/debug/deps/libmultiboot2-c4ce652ef073a510.rmeta --extern volatile=/opt/rustwide/target/debug/deps/libvolatile-6dafccef9d0f549a.rmeta --cap-lints=warn --crate-version 0.1.0` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "fbd527fb8e3a741ebd09a3726ba171d6067ddaebdd5f5d8afc2430ca1de934c7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fbd527fb8e3a741ebd09a3726ba171d6067ddaebdd5f5d8afc2430ca1de934c7", kill_on_drop: false }`
[INFO] [stdout] fbd527fb8e3a741ebd09a3726ba171d6067ddaebdd5f5d8afc2430ca1de934c7