[INFO] fetching crate syndicate 0.23.0...
[INFO] documenting syndicate-0.23.0 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate syndicate 0.23.0 into /workspace/builds/worker-17/source
[INFO] validating manifest of crates.io crate syndicate 0.23.0 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 syndicate 0.23.0
[INFO] finished tweaking crates.io crate syndicate 0.23.0
[INFO] tweaked toml for crates.io crate syndicate 0.23.0 written to /workspace/builds/worker-17/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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-17/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-17/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] 882fadb347c65a546690130b700f7fb83621281c1085363ec6b6b7df1d8c4a77
[INFO] running `Command { std: "docker" "start" "-a" "882fadb347c65a546690130b700f7fb83621281c1085363ec6b6b7df1d8c4a77", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "882fadb347c65a546690130b700f7fb83621281c1085363ec6b6b7df1d8c4a77", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "882fadb347c65a546690130b700f7fb83621281c1085363ec6b6b7df1d8c4a77", kill_on_drop: false }`
[INFO] [stdout] 882fadb347c65a546690130b700f7fb83621281c1085363ec6b6b7df1d8c4a77
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-17/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-17/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] 135f3db2741da8415f34da4e672941192bd2d13c8fbd1421773797b272571bfb
[INFO] running `Command { std: "docker" "start" "-a" "135f3db2741da8415f34da4e672941192bd2d13c8fbd1421773797b272571bfb", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.39
[INFO] [stderr]    Compiling unicode-ident v1.0.0
[INFO] [stderr]    Compiling syn v1.0.95
[INFO] [stderr]    Compiling libc v0.2.126
[INFO] [stderr]    Compiling memchr v2.5.0
[INFO] [stderr]    Compiling serde_derive v1.0.137
[INFO] [stderr]    Compiling serde v1.0.137
[INFO] [stderr]    Compiling unicode-segmentation v1.9.0
[INFO] [stderr]     Checking pin-project-lite v0.2.9
[INFO] [stderr]    Compiling futures-core v0.3.21
[INFO] [stderr]     Checking regex-syntax v0.6.26
[INFO] [stderr]     Checking futures-sink v0.3.21
[INFO] [stderr]    Compiling log v0.4.17
[INFO] [stderr]    Compiling vec_map v0.8.2
[INFO] [stderr]    Compiling strsim v0.8.0
[INFO] [stderr]    Compiling ansi_term v0.12.1
[INFO] [stderr]    Compiling futures-channel v0.3.21
[INFO] [stderr]    Compiling futures-task v0.3.21
[INFO] [stderr]    Compiling base64 v0.13.0
[INFO] [stderr]    Compiling futures-util v0.3.21
[INFO] [stderr]    Compiling dtoa v0.4.8
[INFO] [stderr]     Checking once_cell v1.12.0
[INFO] [stderr]     Checking slab v0.4.6
[INFO] [stderr]     Checking futures-io v0.3.21
[INFO] [stderr]    Compiling serde_json v1.0.81
[INFO] [stderr]    Compiling convert_case v0.4.0
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]    Compiling glob v0.3.0
[INFO] [stderr]    Compiling parking_lot_core v0.8.5
[INFO] [stderr]     Checking ryu v1.0.10
[INFO] [stderr]     Checking itoa v1.0.2
[INFO] [stderr]     Checking bytes v1.1.0
[INFO] [stderr]     Checking subtle v2.4.1
[INFO] [stderr]    Compiling num-traits v0.2.15
[INFO] [stderr]    Compiling num-integer v0.1.45
[INFO] [stderr]    Compiling num-bigint v0.4.3
[INFO] [stderr]    Compiling num-iter v0.1.43
[INFO] [stderr]    Compiling num-rational v0.4.0
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr]     Checking tracing-core v0.1.26
[INFO] [stderr]     Checking instant v0.1.12
[INFO] [stderr]     Checking sharded-slab v0.1.4
[INFO] [stderr]     Checking crypto-mac v0.11.1
[INFO] [stderr]     Checking hmac v0.11.0
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]     Checking thread_local v1.1.4
[INFO] [stderr]    Compiling quote v1.0.18
[INFO] [stderr]     Checking regex-automata v0.1.10
[INFO] [stderr]     Checking tracing-log v0.1.3
[INFO] [stderr]    Compiling aho-corasick v0.7.18
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]     Checking num_cpus v1.13.1
[INFO] [stderr]     Checking getrandom v0.2.6
[INFO] [stderr]     Checking matchers v0.0.1
[INFO] [stderr]    Compiling num-complex v0.4.1
[INFO] [stderr]    Compiling clap v2.34.0
[INFO] [stderr]     Checking parking_lot v0.11.2
[INFO] [stderr]     Checking chrono v0.4.19
[INFO] [stderr]     Checking regex v1.5.6
[INFO] [stderr]     Checking num v0.4.0
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]    Compiling structopt-derive v0.4.18
[INFO] [stderr]    Compiling thiserror-impl v1.0.31
[INFO] [stderr]    Compiling tracing-attributes v0.1.21
[INFO] [stderr]    Compiling futures-macro v0.3.21
[INFO] [stderr]    Compiling tokio-macros v1.7.0
[INFO] [stderr]    Compiling pin-project-internal v1.0.10
[INFO] [stderr]     Checking tokio v1.18.2
[INFO] [stderr]     Checking pin-project v1.0.10
[INFO] [stderr]    Compiling thiserror v1.0.31
[INFO] [stderr]     Checking tracing v0.1.34
[INFO] [stderr]    Compiling structopt v0.3.26
[INFO] [stderr]     Checking tracing-futures v0.2.5
[INFO] [stderr]     Checking tokio-util v0.6.10
[INFO] [stderr]     Checking futures-executor v0.3.21
[INFO] [stderr]     Checking futures v0.3.21
[INFO] [stderr]     Checking serde_bytes v0.11.6
[INFO] [stderr]     Checking tracing-serde v0.1.3
[INFO] [stderr]     Checking preserves v2.3.0
[INFO] [stderr]     Checking tracing-subscriber v0.2.25
[INFO] [stderr]     Checking preserves-schema v2.4.0
[INFO] [stderr]    Compiling syndicate v0.23.0 (/opt/rustwide/workdir)
[INFO] [stderr]  Documenting syndicate v0.23.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(min_specialization)]
[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 `syndicate`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name syndicate src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=fa18cd80cb8e81a2 -L dependency=/opt/rustwide/target/debug/deps --extern bytes=/opt/rustwide/target/debug/deps/libbytes-57de1f6d7c9c6f6c.rmeta --extern futures=/opt/rustwide/target/debug/deps/libfutures-d96df781d2bac963.rmeta --extern getrandom=/opt/rustwide/target/debug/deps/libgetrandom-daa06b96ef1fca2e.rmeta --extern hmac=/opt/rustwide/target/debug/deps/libhmac-640528cc6be4709f.rmeta --extern lazy_static=/opt/rustwide/target/debug/deps/liblazy_static-1479f2b7adeaa2b6.rmeta --extern parking_lot=/opt/rustwide/target/debug/deps/libparking_lot-91887e4bb2769102.rmeta --extern preserves=/opt/rustwide/target/debug/deps/libpreserves-7524d65b413de074.rmeta --extern preserves_schema=/opt/rustwide/target/debug/deps/libpreserves_schema-630a63dabb9ebd92.rmeta --extern sha2=/opt/rustwide/target/debug/deps/libsha2-53f15e953fc1e887.rmeta --extern tokio=/opt/rustwide/target/debug/deps/libtokio-150c3cb075a56821.rmeta --extern tokio_util=/opt/rustwide/target/debug/deps/libtokio_util-50f5e21b7a333ee4.rmeta --extern tracing=/opt/rustwide/target/debug/deps/libtracing-50ac2cb6cb63a92f.rmeta --extern tracing_futures=/opt/rustwide/target/debug/deps/libtracing_futures-6822f496280752ce.rmeta --extern tracing_subscriber=/opt/rustwide/target/debug/deps/libtracing_subscriber-d2fc95085b852f80.rmeta --cap-lints=warn --crate-version 0.23.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "135f3db2741da8415f34da4e672941192bd2d13c8fbd1421773797b272571bfb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "135f3db2741da8415f34da4e672941192bd2d13c8fbd1421773797b272571bfb", kill_on_drop: false }`
[INFO] [stdout] 135f3db2741da8415f34da4e672941192bd2d13c8fbd1421773797b272571bfb