[INFO] cloning repository https://github.com/twitchax/sudoku_solver
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/twitchax/sudoku_solver" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftwitchax%2Fsudoku_solver", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftwitchax%2Fsudoku_solver'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] dde99062fe11ecedc05036db3ef7b0ea0cef930c
[INFO] documenting twitchax/sudoku_solver 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%2Ftwitchax%2Fsudoku_solver" "/workspace/builds/worker-11/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/twitchax/sudoku_solver 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 git repo https://github.com/twitchax/sudoku_solver
[INFO] finished tweaking git repo https://github.com/twitchax/sudoku_solver
[INFO] tweaked toml for git repo https://github.com/twitchax/sudoku_solver written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate git repo https://github.com/twitchax/sudoku_solver 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-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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] 707dedcf365c01c7adccf2dd61906ccd05dba2d42404e896ee2fa9a89ff9cdd6
[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" "707dedcf365c01c7adccf2dd61906ccd05dba2d42404e896ee2fa9a89ff9cdd6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "707dedcf365c01c7adccf2dd61906ccd05dba2d42404e896ee2fa9a89ff9cdd6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "707dedcf365c01c7adccf2dd61906ccd05dba2d42404e896ee2fa9a89ff9cdd6", kill_on_drop: false }`
[INFO] [stdout] 707dedcf365c01c7adccf2dd61906ccd05dba2d42404e896ee2fa9a89ff9cdd6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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] df2178363a9cd3776c236e5401771340549a5f582816d83c6b68b57b8dbe750f
[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" "df2178363a9cd3776c236e5401771340549a5f582816d83c6b68b57b8dbe750f", kill_on_drop: false }`
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking core_affinity v0.5.10
[INFO] [stderr]     Checking chrono v0.4.13
[INFO] [stderr]     Checking crossbeam-utils v0.7.2
[INFO] [stderr]     Checking colored v1.9.3
[INFO] [stderr]     Checking crossbeam-epoch v0.8.2
[INFO] [stderr]     Checking crossbeam-queue v0.2.3
[INFO] [stderr]     Checking crossbeam-channel v0.4.2
[INFO] [stderr]     Checking simple_logger v1.6.0
[INFO] [stderr]     Checking crossbeam-deque v0.7.3
[INFO] [stderr]     Checking crossbeam v0.7.3
[INFO] [stderr]  Documenting sudoku_solver v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:3:12
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(test)]
[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 `sudoku_solver`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type bin --crate-name sudoku_solver src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=e906410bf8951fae -L dependency=/opt/rustwide/target/debug/deps --extern core_affinity=/opt/rustwide/target/debug/deps/libcore_affinity-ea8e70b9a8cc3cfc.rmeta --extern crossbeam=/opt/rustwide/target/debug/deps/libcrossbeam-fcc81c8b41d65bc2.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-75e05042539405e4.rmeta --extern once_cell=/opt/rustwide/target/debug/deps/libonce_cell-abb986e67b5169ab.rmeta --extern simple_logger=/opt/rustwide/target/debug/deps/libsimple_logger-c49a8e754f78ac61.rmeta --cap-lints=warn --crate-version 0.0.1` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "df2178363a9cd3776c236e5401771340549a5f582816d83c6b68b57b8dbe750f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "df2178363a9cd3776c236e5401771340549a5f582816d83c6b68b57b8dbe750f", kill_on_drop: false }`
[INFO] [stdout] df2178363a9cd3776c236e5401771340549a5f582816d83c6b68b57b8dbe750f