[INFO] cloning repository https://github.com/Avemeno/captcha-splitter
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Avemeno/captcha-splitter" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAvemeno%2Fcaptcha-splitter", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAvemeno%2Fcaptcha-splitter'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ff475eeab887fc9d6bc39f681ed235932b5d1274
[INFO] documenting Avemeno/captcha-splitter 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%2FAvemeno%2Fcaptcha-splitter" "/workspace/builds/worker-30/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-30/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Avemeno/captcha-splitter 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/Avemeno/captcha-splitter
[INFO] finished tweaking git repo https://github.com/Avemeno/captcha-splitter
[INFO] tweaked toml for git repo https://github.com/Avemeno/captcha-splitter written to /workspace/builds/worker-30/source/Cargo.toml
[INFO] crate git repo https://github.com/Avemeno/captcha-splitter 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]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded clap_derive v3.0.0-rc.8
[INFO] [stderr]   Downloaded clap v3.0.0-rc.8
[INFO] [stderr]   Downloaded capturing-glob v0.1.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-30/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-30/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] 6e65e188557a23166319e17887ca5fc3d768985b325c67d2a26cd81ab22febbe
[INFO] running `Command { std: "docker" "start" "-a" "6e65e188557a23166319e17887ca5fc3d768985b325c67d2a26cd81ab22febbe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6e65e188557a23166319e17887ca5fc3d768985b325c67d2a26cd81ab22febbe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6e65e188557a23166319e17887ca5fc3d768985b325c67d2a26cd81ab22febbe", kill_on_drop: false }`
[INFO] [stdout] 6e65e188557a23166319e17887ca5fc3d768985b325c67d2a26cd81ab22febbe
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-30/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-30/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] f22c22d765caae866b0522a87554a94f227e54da993ce2cbd31707f6fc361d53
[INFO] running `Command { std: "docker" "start" "-a" "f22c22d765caae866b0522a87554a94f227e54da993ce2cbd31707f6fc361d53", kill_on_drop: false }`
[INFO] [stderr]    Compiling crossbeam-utils v0.8.5
[INFO] [stderr]    Compiling crossbeam-epoch v0.9.5
[INFO] [stderr]    Compiling version_check v0.9.3
[INFO] [stderr]    Compiling proc-macro2 v1.0.34
[INFO] [stderr]    Compiling rayon-core v1.9.1
[INFO] [stderr]    Compiling syn v1.0.83
[INFO] [stderr]     Checking either v1.6.1
[INFO] [stderr]     Checking adler32 v1.2.0
[INFO] [stderr]     Checking weezl v0.1.5
[INFO] [stderr]     Checking hashbrown v0.11.2
[INFO] [stderr]     Checking color_quant v1.1.0
[INFO] [stderr]     Checking termcolor v1.1.2
[INFO] [stderr]     Checking bytemuck v1.7.3
[INFO] [stderr]     Checking textwrap v0.14.2
[INFO] [stderr]     Checking strsim v0.10.0
[INFO] [stderr]     Checking scoped_threadpool v0.1.9
[INFO] [stderr]     Checking capturing-glob v0.1.1
[INFO] [stderr]    Compiling memoffset v0.6.5
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling rayon v1.5.1
[INFO] [stderr]    Compiling miniz_oxide v0.4.4
[INFO] [stderr]    Compiling indexmap v1.7.0
[INFO] [stderr]    Compiling num-rational v0.3.2
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]     Checking num_cpus v1.13.1
[INFO] [stderr]     Checking os_str_bytes v6.0.0
[INFO] [stderr]     Checking miniz_oxide v0.3.7
[INFO] [stderr]     Checking deflate v0.8.6
[INFO] [stderr]     Checking gif v0.11.3
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]     Checking png v0.16.8
[INFO] [stderr]     Checking crossbeam-channel v0.5.1
[INFO] [stderr]    Compiling quote v1.0.10
[INFO] [stderr]     Checking crossbeam-deque v0.8.1
[INFO] [stderr]    Compiling clap_derive v3.0.0-rc.8
[INFO] [stderr]     Checking jpeg-decoder v0.1.22
[INFO] [stderr]     Checking tiff v0.6.1
[INFO] [stderr]     Checking clap v3.0.0-rc.8
[INFO] [stderr]     Checking image v0.23.14
[INFO] [stderr]  Documenting margo-captcha-splitter 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(let_else)]
[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 `margo-captcha-splitter`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2021 --crate-type bin --crate-name margo_captcha_splitter src/main.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=61a80a12b321f6f6 -L dependency=/opt/rustwide/target/debug/deps --extern capturing_glob=/opt/rustwide/target/debug/deps/libcapturing_glob-3476439ca192284f.rmeta --extern clap=/opt/rustwide/target/debug/deps/libclap-3b6c0f889ec099f2.rmeta --extern image=/opt/rustwide/target/debug/deps/libimage-2ffcc739ae11b65d.rmeta --extern rayon=/opt/rustwide/target/debug/deps/librayon-845b00f2140dffdd.rmeta --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "f22c22d765caae866b0522a87554a94f227e54da993ce2cbd31707f6fc361d53", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f22c22d765caae866b0522a87554a94f227e54da993ce2cbd31707f6fc361d53", kill_on_drop: false }`
[INFO] [stdout] f22c22d765caae866b0522a87554a94f227e54da993ce2cbd31707f6fc361d53