[INFO] fetching crate iter-skak 0.2.0...
[INFO] documenting iter-skak-0.2.0 against 1.75.0 for beta-1.76-rustdoc-1
[INFO] extracting crate iter-skak 0.2.0 into /workspace/builds/worker-3-tc1/source
[INFO] validating manifest of crates.io crate iter-skak 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 iter-skak 0.2.0
[INFO] finished tweaking crates.io crate iter-skak 0.2.0
[INFO] tweaked toml for crates.io crate iter-skak 0.2.0 written to /workspace/builds/worker-3-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] 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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] 4a25b462e83dddabb9aee03f608f93b7586d007e0461f756e87b7ba4e8a993a7
[INFO] running `Command { std: "docker" "start" "-a" "4a25b462e83dddabb9aee03f608f93b7586d007e0461f756e87b7ba4e8a993a7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4a25b462e83dddabb9aee03f608f93b7586d007e0461f756e87b7ba4e8a993a7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4a25b462e83dddabb9aee03f608f93b7586d007e0461f756e87b7ba4e8a993a7", kill_on_drop: false }`
[INFO] [stdout] 4a25b462e83dddabb9aee03f608f93b7586d007e0461f756e87b7ba4e8a993a7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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] 7205a05b570eba523d9a0e518126c03c0bfa6f44efbec366b6b4c3560bd47569
[INFO] running `Command { std: "docker" "start" "-a" "7205a05b570eba523d9a0e518126c03c0bfa6f44efbec366b6b4c3560bd47569", kill_on_drop: false }`
[INFO] [stderr]  Documenting iter-skak 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(core_intrinsics, rustc_attrs, iter_advance_by, try_trait_v2, try_blocks)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `rustc_attrs` is internal to the compiler or standard library
[INFO] [stdout]  --> src/lib.rs:1:29
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(core_intrinsics, rustc_attrs, iter_advance_by, try_trait_v2, try_blocks)]
[INFO] [stdout]   |                             ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: using it is strongly discouraged
[INFO] [stdout]   = note: `#[warn(internal_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0053]: method `advance_by` has an incompatible type for trait
[INFO] [stdout]    --> src/lib.rs:110:43
[INFO] [stdout]     |
[INFO] [stdout] 110 |     fn advance_by(&mut self, n: usize) -> Result<(), usize> {
[INFO] [stdout]     |                                           ^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |                                           |
[INFO] [stdout]     |                                           expected `std::num::NonZeroUsize`, found `usize`
[INFO] [stdout]     |                                           help: change the output type to match the trait: `std::result::Result<(), std::num::NonZeroUsize>`
[INFO] [stdout]     |
[INFO] [stdout]     = note: expected signature `fn(&mut Skip<I>, _) -> std::result::Result<_, std::num::NonZeroUsize>`
[INFO] [stdout]                found signature `fn(&mut Skip<I>, _) -> std::result::Result<_, usize>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0053, E0554.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0053`.
[INFO] [stdout] 
[INFO] [stderr] error: could not document `iter-skak`
[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 lib --crate-name iter_skak src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=ff37fed8860f2e03 -L dependency=/opt/rustwide/target/debug/deps --cap-lints=warn --crate-version 0.2.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "7205a05b570eba523d9a0e518126c03c0bfa6f44efbec366b6b4c3560bd47569", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7205a05b570eba523d9a0e518126c03c0bfa6f44efbec366b6b4c3560bd47569", kill_on_drop: false }`
[INFO] [stdout] 7205a05b570eba523d9a0e518126c03c0bfa6f44efbec366b6b4c3560bd47569
