[INFO] cloning repository https://github.com/hdoordt/four-wheel-drive-demo
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/hdoordt/four-wheel-drive-demo" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhdoordt%2Ffour-wheel-drive-demo", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhdoordt%2Ffour-wheel-drive-demo'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 53a48d91b18c96d9f30fcf4ea35326cf25832d50
[INFO] documenting hdoordt/four-wheel-drive-demo against 1.61.0 for beta-1.62-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhdoordt%2Ffour-wheel-drive-demo" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/hdoordt/four-wheel-drive-demo 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] removed /workspace/builds/worker-7/source/.cargo/config
[INFO] started tweaking git repo https://github.com/hdoordt/four-wheel-drive-demo
[INFO] finished tweaking git repo https://github.com/hdoordt/four-wheel-drive-demo
[INFO] tweaked toml for git repo https://github.com/hdoordt/four-wheel-drive-demo written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/hdoordt/four-wheel-drive-demo 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] [stderr]     Updating git repository `https://github.com/hdoordt/ring-buf-rs.git`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded cortex-m-rt-macros v0.1.8
[INFO] [stderr]   Downloaded usb-device v0.2.5
[INFO] [stderr]   Downloaded stm32-usbd v0.5.1
[INFO] [stderr]   Downloaded embedded-hal v0.2.3
[INFO] [stderr]   Downloaded cortex-m-rt v0.6.12
[INFO] [stderr]   Downloaded r0 v0.2.2
[INFO] [stderr]   Downloaded heapless v0.3.7
[INFO] [stderr]   Downloaded stm32f3 v0.9.0
[INFO] [stderr]   Downloaded m v0.1.1
[INFO] [stderr]   Downloaded cortex-m-semihosting v0.3.5
[INFO] [stderr]   Downloaded stm32f3xx-hal v0.4.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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] 4491140e077378daa103dea799bf91154d44190483b04c7e77492820e52400d0
[INFO] running `Command { std: "docker" "start" "-a" "4491140e077378daa103dea799bf91154d44190483b04c7e77492820e52400d0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4491140e077378daa103dea799bf91154d44190483b04c7e77492820e52400d0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4491140e077378daa103dea799bf91154d44190483b04c7e77492820e52400d0", kill_on_drop: false }`
[INFO] [stdout] 4491140e077378daa103dea799bf91154d44190483b04c7e77492820e52400d0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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] [stdout] 4c85b9414b83424740cf2f98212cb805c2b0e212d8754c566433c18c454d5b6d
[INFO] running `Command { std: "docker" "start" "-a" "4c85b9414b83424740cf2f98212cb805c2b0e212d8754c566433c18c454d5b6d", kill_on_drop: false }`
[INFO] [stderr]    Compiling typenum v1.11.2
[INFO] [stderr]    Compiling cortex-m v0.6.2
[INFO] [stderr]     Checking stable_deref_trait v1.1.1
[INFO] [stderr]    Compiling proc-macro2 v1.0.9
[INFO] [stderr]    Compiling unicode-xid v0.2.0
[INFO] [stderr]     Checking vcell v0.1.2
[INFO] [stderr]    Compiling syn v1.0.16
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling cortex-m-rt v0.6.12
[INFO] [stderr]     Checking nb v0.1.2
[INFO] [stderr]    Compiling stm32f3 v0.9.0
[INFO] [stderr]     Checking r0 v0.2.2
[INFO] [stderr]    Compiling stm32-usbd v0.5.1
[INFO] [stderr]    Compiling cortex-m-semihosting v0.3.5
[INFO] [stderr]     Checking usb-device v0.2.5
[INFO] [stderr]     Checking void v1.0.2
[INFO] [stderr]     Checking m v0.1.1
[INFO] [stderr]    Compiling bare-metal v0.2.5
[INFO] [stderr]    Compiling cast v0.2.3
[INFO] [stderr]     Checking volatile-register v0.2.0
[INFO] [stderr]     Checking embedded-hal v0.2.3
[INFO] [stderr]     Checking hash32 v0.1.1
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]     Checking generic-array v0.12.3
[INFO] [stderr]     Checking generic-array v0.13.2
[INFO] [stderr]     Checking generic-array v0.11.1
[INFO] [stderr]     Checking heapless v0.3.7
[INFO] [stderr]     Checking as-slice v0.1.3
[INFO] [stderr]     Checking aligned v0.3.2
[INFO] [stderr]     Checking ring_buf v0.1.0 (https://github.com/hdoordt/ring-buf-rs.git?branch=master#c6f7feb0)
[INFO] [stderr]    Compiling cortex-m-rt-macros v0.1.8
[INFO] [stderr]     Checking stm32f3xx-hal v0.4.1
[INFO] [stderr]  Documenting four-wd-demo 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:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(never_type)]
[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 `four-wd-demo`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name four_wd_demo src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=45298334d252927e -L dependency=/opt/rustwide/target/debug/deps --extern bare_metal=/opt/rustwide/target/debug/deps/libbare_metal-68ccca286c5ae07d.rmeta --extern cortex_m=/opt/rustwide/target/debug/deps/libcortex_m-524a4355845278f0.rmeta --extern cortex_m_rt=/opt/rustwide/target/debug/deps/libcortex_m_rt-06a9fa2d9042ee36.rmeta --extern cortex_m_semihosting=/opt/rustwide/target/debug/deps/libcortex_m_semihosting-cf8a2c6fe03fd61f.rmeta --extern embedded_hal=/opt/rustwide/target/debug/deps/libembedded_hal-7d2e4236461c8c2a.rmeta --extern heapless=/opt/rustwide/target/debug/deps/libheapless-859984269d35e035.rmeta --extern m=/opt/rustwide/target/debug/deps/libm-81f4c99e97e523d5.rmeta --extern nb=/opt/rustwide/target/debug/deps/libnb-7211536e8dee8ba9.rmeta --extern ring_buf=/opt/rustwide/target/debug/deps/libring_buf-5d33b39f39bf45b7.rmeta --extern stm32f3xx_hal=/opt/rustwide/target/debug/deps/libstm32f3xx_hal-860aa8b445515983.rmeta --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "4c85b9414b83424740cf2f98212cb805c2b0e212d8754c566433c18c454d5b6d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4c85b9414b83424740cf2f98212cb805c2b0e212d8754c566433c18c454d5b6d", kill_on_drop: false }`
[INFO] [stdout] 4c85b9414b83424740cf2f98212cb805c2b0e212d8754c566433c18c454d5b6d