[INFO] fetching crate concgc 0.1.1...
[INFO] documenting concgc-0.1.1 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate concgc 0.1.1 into /workspace/builds/worker-79/source
[INFO] validating manifest of crates.io crate concgc 0.1.1 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 concgc 0.1.1
[INFO] finished tweaking crates.io crate concgc 0.1.1
[INFO] tweaked toml for crates.io crate concgc 0.1.1 written to /workspace/builds/worker-79/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]  Downloading crates ...
[INFO] [stderr]   Downloaded hashbrown v0.7.2
[INFO] [stderr]   Downloaded derive_deref v1.1.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/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] 8208d573f1c5b7b720ba5a1c5aa82b8f17dca35d9c85e3f2c7f3fc79fb04e02f
[INFO] running `Command { std: "docker" "start" "-a" "8208d573f1c5b7b720ba5a1c5aa82b8f17dca35d9c85e3f2c7f3fc79fb04e02f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8208d573f1c5b7b720ba5a1c5aa82b8f17dca35d9c85e3f2c7f3fc79fb04e02f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8208d573f1c5b7b720ba5a1c5aa82b8f17dca35d9c85e3f2c7f3fc79fb04e02f", kill_on_drop: false }`
[INFO] [stdout] 8208d573f1c5b7b720ba5a1c5aa82b8f17dca35d9c85e3f2c7f3fc79fb04e02f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/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] 7edce7b2fdb3300806744dc1de8a1881abe1465c4b539897174bead9d7b145d8
[INFO] running `Command { std: "docker" "start" "-a" "7edce7b2fdb3300806744dc1de8a1881abe1465c4b539897174bead9d7b145d8", 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 autocfg v1.1.0
[INFO] [stderr]     Checking ahash v0.3.8
[INFO] [stderr]    Compiling hashbrown v0.7.2
[INFO] [stderr]    Compiling quote v1.0.18
[INFO] [stderr]    Compiling derive_deref v1.1.1
[INFO] [stderr]  Documenting concgc v0.1.1 (/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(box_syntax)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(box_into_raw_non_null)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(map_first_last)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 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 `concgc`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name concgc src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=0a2e8ba285ece72c -L dependency=/opt/rustwide/target/debug/deps --extern derive_deref=/opt/rustwide/target/debug/deps/libderive_deref-cdd0282d80d70908.so --extern hashbrown=/opt/rustwide/target/debug/deps/libhashbrown-7be602de7cc468a3.rmeta --extern spin=/opt/rustwide/target/debug/deps/libspin-f07759e3f4294fd6.rmeta --cap-lints=warn --crate-version 0.1.1` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "7edce7b2fdb3300806744dc1de8a1881abe1465c4b539897174bead9d7b145d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7edce7b2fdb3300806744dc1de8a1881abe1465c4b539897174bead9d7b145d8", kill_on_drop: false }`
[INFO] [stdout] 7edce7b2fdb3300806744dc1de8a1881abe1465c4b539897174bead9d7b145d8