[INFO] cloning repository https://github.com/DaAitch/sul
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/DaAitch/sul" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FDaAitch%2Fsul", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FDaAitch%2Fsul'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e628984544d0335eb11f74cabbd36996eafe54a9
[INFO] documenting DaAitch/sul 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%2FDaAitch%2Fsul" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/DaAitch/sul 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/DaAitch/sul
[INFO] finished tweaking git repo https://github.com/DaAitch/sul
[INFO] tweaked toml for git repo https://github.com/DaAitch/sul written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/DaAitch/sul 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]  Downloading crates ...
[INFO] [stderr]   Downloaded serde_yaml v0.8.21
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 263bdba17dd852ab9969ebc3a450e386f405ab55986dfb446c402f6aea3e95e1
[INFO] running `Command { std: "docker" "start" "-a" "263bdba17dd852ab9969ebc3a450e386f405ab55986dfb446c402f6aea3e95e1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "263bdba17dd852ab9969ebc3a450e386f405ab55986dfb446c402f6aea3e95e1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "263bdba17dd852ab9969ebc3a450e386f405ab55986dfb446c402f6aea3e95e1", kill_on_drop: false }`
[INFO] [stdout] 263bdba17dd852ab9969ebc3a450e386f405ab55986dfb446c402f6aea3e95e1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] b40ca9cb216612f5e410df61657c07717c4034ae4e3ae12d2b2413ab0ff3f5f7
[INFO] running `Command { std: "docker" "start" "-a" "b40ca9cb216612f5e410df61657c07717c4034ae4e3ae12d2b2413ab0ff3f5f7", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.32
[INFO] [stderr]    Compiling syn v1.0.81
[INFO] [stderr]    Compiling libc v0.2.107
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]    Compiling futures-core v0.3.17
[INFO] [stderr]    Compiling futures-channel v0.3.17
[INFO] [stderr]    Compiling futures-task v0.3.17
[INFO] [stderr]    Compiling pin-project-lite v0.2.7
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling scopeguard v1.1.0
[INFO] [stderr]     Checking smallvec v1.7.0
[INFO] [stderr]    Compiling futures-sink v0.3.17
[INFO] [stderr]     Checking futures-io v0.3.17
[INFO] [stderr]    Compiling hashbrown v0.11.2
[INFO] [stderr]    Compiling once_cell v1.8.0
[INFO] [stderr]    Compiling pin-utils v0.1.0
[INFO] [stderr]    Compiling slab v0.4.5
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]     Checking linked-hash-map v0.5.4
[INFO] [stderr]     Checking unicode-xid v0.2.2
[INFO] [stderr]    Compiling try-lock v0.2.3
[INFO] [stderr]    Compiling serde_json v1.0.71
[INFO] [stderr]    Compiling dtoa v0.4.8
[INFO] [stderr]    Compiling tower-service v0.3.1
[INFO] [stderr]    Compiling httpdate v1.0.2
[INFO] [stderr]    Compiling parking_lot_core v0.8.5
[INFO] [stderr]    Compiling futures-macro v0.3.17
[INFO] [stderr]    Compiling proc-macro-nested v0.1.7
[INFO] [stderr]    Compiling futures-util v0.3.17
[INFO] [stderr]    Compiling tokio v1.14.0
[INFO] [stderr]    Compiling indexmap v1.7.0
[INFO] [stderr]    Compiling serde_derive v1.0.130
[INFO] [stderr]     Checking instant v0.1.12
[INFO] [stderr]     Checking lock_api v0.4.5
[INFO] [stderr]    Compiling httparse v1.5.1
[INFO] [stderr]    Compiling tracing-core v0.1.21
[INFO] [stderr]    Compiling http v0.2.5
[INFO] [stderr]     Checking yaml-rust v0.4.5
[INFO] [stderr]    Compiling tracing v0.1.29
[INFO] [stderr]     Checking want v0.3.0
[INFO] [stderr]     Checking quote v1.0.10
[INFO] [stderr]    Compiling signal-hook-registry v1.4.0
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling mio v0.7.14
[INFO] [stderr]    Compiling socket2 v0.4.2
[INFO] [stderr]    Compiling http-body v0.4.4
[INFO] [stderr]    Compiling parking_lot v0.11.2
[INFO] [stderr]    Compiling tokio-macros v1.6.0
[INFO] [stderr]     Checking tokio-util v0.6.9
[INFO] [stderr]     Checking h2 v0.3.7
[INFO] [stderr]     Checking futures-executor v0.3.17
[INFO] [stderr]     Checking futures v0.3.17
[INFO] [stderr]     Checking serde_yaml v0.8.21
[INFO] [stderr]     Checking hyper v0.14.15
[INFO] [stderr]  Documenting sul v0.0.0 (/opt/rustwide/workdir/sul)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> sul/src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(proc_macro_span)]
[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 `sul`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type proc-macro --crate-name sul sul/src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=f22d3c7ebd71b8f7 -L dependency=/opt/rustwide/target/debug/deps --extern hyper=/opt/rustwide/target/debug/deps/libhyper-fd34feebb9828fef.rmeta --extern proc_macro2=/opt/rustwide/target/debug/deps/libproc_macro2-9d70977442b39594.rmeta --extern quote=/opt/rustwide/target/debug/deps/libquote-39df57aa5bfcb361.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-4aef6d342d335a18.rmeta --extern serde_yaml=/opt/rustwide/target/debug/deps/libserde_yaml-44a22ed7c11ad390.rmeta --extern syn=/opt/rustwide/target/debug/deps/libsyn-93c30f06ce3ebfa7.rmeta --extern proc_macro --cap-lints=warn --crate-version 0.0.0` (exit status: 1)
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "b40ca9cb216612f5e410df61657c07717c4034ae4e3ae12d2b2413ab0ff3f5f7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b40ca9cb216612f5e410df61657c07717c4034ae4e3ae12d2b2413ab0ff3f5f7", kill_on_drop: false }`
[INFO] [stdout] b40ca9cb216612f5e410df61657c07717c4034ae4e3ae12d2b2413ab0ff3f5f7