[INFO] fetching crate singleton-manager 0.1.3...
[INFO] documenting singleton-manager-0.1.3 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate singleton-manager 0.1.3 into /workspace/builds/worker-28/source
[INFO] validating manifest of crates.io crate singleton-manager 0.1.3 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-28/source/rust-toolchain
[INFO] started tweaking crates.io crate singleton-manager 0.1.3
[INFO] finished tweaking crates.io crate singleton-manager 0.1.3
[INFO] tweaked toml for crates.io crate singleton-manager 0.1.3 written to /workspace/builds/worker-28/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[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-28/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-28/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] ae601faab89dd7fa3bfcd21047d56ed452144469a6bd47e61ddb6e182333de89
[INFO] running `Command { std: "docker" "start" "-a" "ae601faab89dd7fa3bfcd21047d56ed452144469a6bd47e61ddb6e182333de89", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ae601faab89dd7fa3bfcd21047d56ed452144469a6bd47e61ddb6e182333de89", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ae601faab89dd7fa3bfcd21047d56ed452144469a6bd47e61ddb6e182333de89", kill_on_drop: false }`
[INFO] [stdout] ae601faab89dd7fa3bfcd21047d56ed452144469a6bd47e61ddb6e182333de89
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-28/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-28/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] 88946f662e164b1eef4ace40ac5aa88c99780e731769efec81b14a651c007d6f
[INFO] running `Command { std: "docker" "start" "-a" "88946f662e164b1eef4ace40ac5aa88c99780e731769efec81b14a651c007d6f", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.126
[INFO] [stderr]     Checking getrandom v0.2.6
[INFO] [stderr]     Checking uuid v0.8.2
[INFO] [stderr]  Documenting singleton-manager v0.1.3 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(fn_traits)]
[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 `singleton-manager`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name singleton_manager src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=08d5c576420a22dc -L dependency=/opt/rustwide/target/debug/deps --extern uuid=/opt/rustwide/target/debug/deps/libuuid-077f891454cb842a.rmeta --cap-lints=warn --crate-version 0.1.3` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "88946f662e164b1eef4ace40ac5aa88c99780e731769efec81b14a651c007d6f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "88946f662e164b1eef4ace40ac5aa88c99780e731769efec81b14a651c007d6f", kill_on_drop: false }`
[INFO] [stdout] 88946f662e164b1eef4ace40ac5aa88c99780e731769efec81b14a651c007d6f