[INFO] fetching crate fn_mut 0.1.0...
[INFO] documenting fn_mut-0.1.0 against beta-2022-05-20 for beta-1.62-rustdoc-1
[INFO] extracting crate fn_mut 0.1.0 into /workspace/builds/worker-34/source
[INFO] validating manifest of crates.io crate fn_mut 0.1.0 on toolchain beta-2022-05-20
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2022-05-20" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate fn_mut 0.1.0
[INFO] finished tweaking crates.io crate fn_mut 0.1.0
[INFO] tweaked toml for crates.io crate fn_mut 0.1.0 written to /workspace/builds/worker-34/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2022-05-20" "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" "+beta-2022-05-20" "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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-34/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-34/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" "+beta-2022-05-20" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] eb9bce110d745056a710c93b8f1dc44714e94cdc2e12719754533e7870942bec
[INFO] running `Command { std: "docker" "start" "-a" "eb9bce110d745056a710c93b8f1dc44714e94cdc2e12719754533e7870942bec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "eb9bce110d745056a710c93b8f1dc44714e94cdc2e12719754533e7870942bec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "eb9bce110d745056a710c93b8f1dc44714e94cdc2e12719754533e7870942bec", kill_on_drop: false }`
[INFO] [stdout] eb9bce110d745056a710c93b8f1dc44714e94cdc2e12719754533e7870942bec
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-34/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-34/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" "+beta-2022-05-20" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 89c2367c2b6c009acf6c38c2e745ffb5d8670df4b50b24420d33e4cd874389cb
[INFO] running `Command { std: "docker" "start" "-a" "89c2367c2b6c009acf6c38c2e745ffb5d8670df4b50b24420d33e4cd874389cb", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.5.0
[INFO] [stderr]    Compiling regex v0.2.11
[INFO] [stderr]     Checking ucd-util v0.1.8
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking unicode-xid v0.0.4
[INFO] [stderr]     Checking quote v0.3.15
[INFO] [stderr]     Checking utf8-ranges v1.0.5
[INFO] [stderr]     Checking lazy_static v0.2.11
[INFO] [stderr]     Checking synom v0.11.3
[INFO] [stderr]     Checking regex-syntax v0.5.6
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]     Checking syn v0.11.11
[INFO] [stderr]     Checking aho-corasick v0.6.10
[INFO] [stderr]  Documenting fn_mut v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> src/lib.rs:67:1
[INFO] [stdout]    |
[INFO] [stdout] 67 | #![feature(proc_macro)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]    |
[INFO] [stdout]    = help: the feature `proc_macro` has been stable since 1.29.0 and no longer requires an attribute to enable
[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 `fn_mut`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type proc-macro --crate-name fn_mut src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=617009f67dab4a62 -L dependency=/opt/rustwide/target/debug/deps --extern lazy_static=/opt/rustwide/target/debug/deps/liblazy_static-4f08b60276848c1e.rmeta --extern quote=/opt/rustwide/target/debug/deps/libquote-31d12ee827a928ff.rmeta --extern regex=/opt/rustwide/target/debug/deps/libregex-a419eb0fc5fa968d.rmeta --extern syn=/opt/rustwide/target/debug/deps/libsyn-41cd242beeb6344d.rmeta --extern proc_macro --cap-lints=warn --crate-version 0.1.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "89c2367c2b6c009acf6c38c2e745ffb5d8670df4b50b24420d33e4cd874389cb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "89c2367c2b6c009acf6c38c2e745ffb5d8670df4b50b24420d33e4cd874389cb", kill_on_drop: false }`
[INFO] [stdout] 89c2367c2b6c009acf6c38c2e745ffb5d8670df4b50b24420d33e4cd874389cb