[INFO] cloning repository https://github.com/guoguojin/rust-example-cli
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/guoguojin/rust-example-cli" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fguoguojin%2Frust-example-cli", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fguoguojin%2Frust-example-cli'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 84d6f22d39c56f4145d3f52407dae83808be4213
[INFO] documenting guoguojin/rust-example-cli against 1.54.0 for beta-1.55-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fguoguojin%2Frust-example-cli" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/guoguojin/rust-example-cli on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/guoguojin/rust-example-cli
[INFO] finished tweaking git repo https://github.com/guoguojin/rust-example-cli
[INFO] tweaked toml for git repo https://github.com/guoguojin/rust-example-cli written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/guoguojin/rust-example-cli already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5d2f5a5abe6bf1bc662e79dc7ddd8d38397c0ddc99c527114911daa7e39996d8
[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" "5d2f5a5abe6bf1bc662e79dc7ddd8d38397c0ddc99c527114911daa7e39996d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5d2f5a5abe6bf1bc662e79dc7ddd8d38397c0ddc99c527114911daa7e39996d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5d2f5a5abe6bf1bc662e79dc7ddd8d38397c0ddc99c527114911daa7e39996d8", kill_on_drop: false }`
[INFO] [stdout] 5d2f5a5abe6bf1bc662e79dc7ddd8d38397c0ddc99c527114911daa7e39996d8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7ce626a14e09b4429302f39057cc4566bcccf66c22cce5e77a06580a1c00d7cf
[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" "7ce626a14e09b4429302f39057cc4566bcccf66c22cce5e77a06580a1c00d7cf", kill_on_drop: false }`
[INFO] [stderr]     Checking memchr v2.0.1
[INFO] [stderr]    Compiling syn v0.14.4
[INFO] [stderr]     Checking serde_json v1.0.22
[INFO] [stderr]     Checking nom v4.0.0
[INFO] [stderr]     Checking config v0.9.0
[INFO] [stderr]    Compiling structopt-derive v0.2.10
[INFO] [stderr]    Compiling serde_derive v1.0.70
[INFO] [stderr]     Checking structopt v0.2.10
[INFO] [stderr]  Documenting example-cli-app 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:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(extern_prelude)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `extern_prelude` has been stable since 1.30.0 and no longer requires an attribute to enable
[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 `example-cli-app`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type bin --crate-name example_cli_app 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 config=/opt/rustwide/target/debug/deps/libconfig-4cc671f8745bb8e2.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-9f94caa99ec71100.rmeta --extern serde_derive=/opt/rustwide/target/debug/deps/libserde_derive-63bc75b60727eccd.so --extern structopt=/opt/rustwide/target/debug/deps/libstructopt-2ba9487544b802de.rmeta --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "7ce626a14e09b4429302f39057cc4566bcccf66c22cce5e77a06580a1c00d7cf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7ce626a14e09b4429302f39057cc4566bcccf66c22cce5e77a06580a1c00d7cf", kill_on_drop: false }`
[INFO] [stdout] 7ce626a14e09b4429302f39057cc4566bcccf66c22cce5e77a06580a1c00d7cf
