[INFO] fetching crate jkcenum_derive 0.2.0...
[INFO] documenting jkcenum_derive-0.2.0 against 1.75.0 for beta-1.76-rustdoc-1
[INFO] extracting crate jkcenum_derive 0.2.0 into /workspace/builds/worker-4-tc1/source
[INFO] validating manifest of crates.io crate jkcenum_derive 0.2.0 on toolchain 1.75.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate jkcenum_derive 0.2.0
[INFO] finished tweaking crates.io crate jkcenum_derive 0.2.0
[INFO] tweaked toml for crates.io crate jkcenum_derive 0.2.0 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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" "+1.75.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded virtue v0.0.15
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "+1.75.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1972a59783ea1b2d0efe2d1c17e8f644717449b047add6ce814b5724aec812b5
[INFO] running `Command { std: "docker" "start" "-a" "1972a59783ea1b2d0efe2d1c17e8f644717449b047add6ce814b5724aec812b5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1972a59783ea1b2d0efe2d1c17e8f644717449b047add6ce814b5724aec812b5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1972a59783ea1b2d0efe2d1c17e8f644717449b047add6ce814b5724aec812b5", kill_on_drop: false }`
[INFO] [stdout] 1972a59783ea1b2d0efe2d1c17e8f644717449b047add6ce814b5724aec812b5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "+1.75.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a87af053f3982e11678014b70de8ad0dbcfd3b6785e3b78aaa96c62bfcc34321
[INFO] running `Command { std: "docker" "start" "-a" "a87af053f3982e11678014b70de8ad0dbcfd3b6785e3b78aaa96c62bfcc34321", kill_on_drop: false }`
[INFO] [stderr]     Checking virtue v0.0.15
[INFO] [stderr]  Documenting jkcenum_derive v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(let_chains)]
[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 `jkcenum_derive`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/rustwide/rustup-home/toolchains/1.75.0-x86_64-unknown-linux-gnu/bin/rustdoc --edition=2021 --crate-type proc-macro --crate-name jkcenum_derive src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=82ef1fe2502d804e -L dependency=/opt/rustwide/target/debug/deps --extern virtue=/opt/rustwide/target/debug/deps/libvirtue-5ccddd6a4db59223.rmeta --extern proc_macro --cap-lints=warn --crate-version 0.2.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "a87af053f3982e11678014b70de8ad0dbcfd3b6785e3b78aaa96c62bfcc34321", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a87af053f3982e11678014b70de8ad0dbcfd3b6785e3b78aaa96c62bfcc34321", kill_on_drop: false }`
[INFO] [stdout] a87af053f3982e11678014b70de8ad0dbcfd3b6785e3b78aaa96c62bfcc34321
