[INFO] fetching crate monotron-synth 0.2.0...
[INFO] documenting monotron-synth-0.2.0 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate monotron-synth 0.2.0 into /workspace/builds/worker-23/source
[INFO] validating manifest of crates.io crate monotron-synth 0.2.0 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 crates.io crate monotron-synth 0.2.0
[INFO] finished tweaking crates.io crate monotron-synth 0.2.0
[INFO] tweaked toml for crates.io crate monotron-synth 0.2.0 written to /workspace/builds/worker-23/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] [stderr]     Blocking waiting for file lock on package cache
[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 libpulse-binding v2.26.0
[INFO] [stderr]   Downloaded libpulse-sys v1.19.3
[INFO] [stderr]   Downloaded libpulse-simple-binding v2.25.0
[INFO] [stderr]   Downloaded num-derive v0.3.3
[INFO] [stderr]   Downloaded libpulse-simple-sys v1.19.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-23/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-23/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] 5352c3d3b5f801c600dc96edf202ff84ef38388c7ab7b0e766c3c8cb0429f640
[INFO] running `Command { std: "docker" "start" "-a" "5352c3d3b5f801c600dc96edf202ff84ef38388c7ab7b0e766c3c8cb0429f640", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5352c3d3b5f801c600dc96edf202ff84ef38388c7ab7b0e766c3c8cb0429f640", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5352c3d3b5f801c600dc96edf202ff84ef38388c7ab7b0e766c3c8cb0429f640", kill_on_drop: false }`
[INFO] [stdout] 5352c3d3b5f801c600dc96edf202ff84ef38388c7ab7b0e766c3c8cb0429f640
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-23/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-23/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] 9773de2efbd34e3944c247c240dfd7200a68c3c9c22264ba0c81a4b1d898c4bb
[INFO] running `Command { std: "docker" "start" "-a" "9773de2efbd34e3944c247c240dfd7200a68c3c9c22264ba0c81a4b1d898c4bb", kill_on_drop: false }`
[INFO] [stderr]  Documenting monotron-synth v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]  --> src/lib.rs:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(const_fn)]
[INFO] [stdout]   |            ^^^^^^^^ feature has been removed
[INFO] [stdout]   |
[INFO] [stdout]   = note: split into finer-grained feature gates
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:359:9
[INFO] [stdout]     |
[INFO] [stdout] 359 |         (intermediate as u8)
[INFO] [stdout]     |         ^                  ^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 359 -         (intermediate as u8)
[INFO] [stdout] 359 +         intermediate as u8
[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; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0557`.
[INFO] [stdout] 
[INFO] [stderr] error: could not document `monotron-synth`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name monotron_synth src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=1af37f74d514a056 -L dependency=/opt/rustwide/target/debug/deps --cap-lints=warn --crate-version 0.2.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "9773de2efbd34e3944c247c240dfd7200a68c3c9c22264ba0c81a4b1d898c4bb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9773de2efbd34e3944c247c240dfd7200a68c3c9c22264ba0c81a4b1d898c4bb", kill_on_drop: false }`
[INFO] [stdout] 9773de2efbd34e3944c247c240dfd7200a68c3c9c22264ba0c81a4b1d898c4bb