[INFO] fetching crate kll-core 0.1.8...
[INFO] documenting kll-core-0.1.8 against 1.76.0 for beta-1.77-rustdoc-1
[INFO] extracting crate kll-core 0.1.8 into /workspace/builds/worker-7-tc1/source
[INFO] validating manifest of crates.io crate kll-core 0.1.8 on toolchain 1.76.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.76.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate kll-core 0.1.8
[INFO] finished tweaking crates.io crate kll-core 0.1.8
[INFO] tweaked toml for crates.io crate kll-core 0.1.8 written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.76.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.76.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded nu-ansi-term v0.49.0
[INFO] [stderr]   Downloaded flexi_logger v0.25.6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.76.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3d5f145acf515cae52e7b9c3f114b31a9a990e21335b278a603cdf3f4351cfc3
[INFO] running `Command { std: "docker" "start" "-a" "3d5f145acf515cae52e7b9c3f114b31a9a990e21335b278a603cdf3f4351cfc3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3d5f145acf515cae52e7b9c3f114b31a9a990e21335b278a603cdf3f4351cfc3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3d5f145acf515cae52e7b9c3f114b31a9a990e21335b278a603cdf3f4351cfc3", kill_on_drop: false }`
[INFO] [stdout] 3d5f145acf515cae52e7b9c3f114b31a9a990e21335b278a603cdf3f4351cfc3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/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" "RUSTFLAGS=--cap-lints=warn" "-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.76.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3b7d3ab9f352529c22389c146f1c5c48f55f31eafd65bd90cfab4540bc840ff0
[INFO] running `Command { std: "docker" "start" "-a" "3b7d3ab9f352529c22389c146f1c5c48f55f31eafd65bd90cfab4540bc840ff0", kill_on_drop: false }`
[INFO] [stderr]     Checking kll-hid v0.1.2
[INFO] [stderr]     Checking log v0.4.20
[INFO] [stderr]    Compiling kll-macros v0.1.2
[INFO] [stderr]    Compiling num-traits v0.2.18
[INFO] [stderr]    Compiling heapless v0.7.17
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling enum-primitive-derive v0.2.2
[INFO] [stderr]  Documenting kll-core v0.1.8 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:9:1
[INFO] [stdout]   |
[INFO] [stdout] 9 | #![feature(let_chains)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 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 `kll-core`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/rustwide/rustup-home/toolchains/1.76.0-x86_64-unknown-linux-gnu/bin/rustdoc --edition=2021 --crate-type lib --crate-name kll_core src/lib.rs -o /opt/rustwide/target/doc --cfg 'feature="default"' --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=efb7245eff960824 -L dependency=/opt/rustwide/target/debug/deps --extern byteorder=/opt/rustwide/target/debug/deps/libbyteorder-18cc870496569bfa.rmeta --extern enum_primitive_derive=/opt/rustwide/target/debug/deps/libenum_primitive_derive-fdbddfcd7faed574.so --extern heapless=/opt/rustwide/target/debug/deps/libheapless-65cb458c8b70ea37.rmeta --extern kll_hid=/opt/rustwide/target/debug/deps/libkll_hid-c85e038665ed6515.rmeta --extern kll_macros=/opt/rustwide/target/debug/deps/libkll_macros-56bee375bd7a692d.so --extern log=/opt/rustwide/target/debug/deps/liblog-7fe0807640814e58.rmeta --extern num_traits=/opt/rustwide/target/debug/deps/libnum_traits-dbe094dd22ea9e5e.rmeta --extern static_assertions=/opt/rustwide/target/debug/deps/libstatic_assertions-2c71fdf3ee9f9afe.rmeta --cap-lints=warn --crate-version 0.1.8` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "3b7d3ab9f352529c22389c146f1c5c48f55f31eafd65bd90cfab4540bc840ff0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3b7d3ab9f352529c22389c146f1c5c48f55f31eafd65bd90cfab4540bc840ff0", kill_on_drop: false }`
[INFO] [stdout] 3b7d3ab9f352529c22389c146f1c5c48f55f31eafd65bd90cfab4540bc840ff0
