[INFO] fetching crate ddcore-rs 0.3.0...
[INFO] documenting ddcore-rs-0.3.0 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate ddcore-rs 0.3.0 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate ddcore-rs 0.3.0 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 ddcore-rs 0.3.0
[INFO] finished tweaking crates.io crate ddcore-rs 0.3.0
[INFO] tweaked toml for crates.io crate ddcore-rs 0.3.0 written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate crates.io crate ddcore-rs 0.3.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.61.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded block-padding v0.3.1
[INFO] [stderr]   Downloaded process-memory v0.4.0
[INFO] [stderr]   Downloaded cbc v0.1.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] 8ace70168e38743b8e86310c583564982c04978f4b93196d6ba911805c60c933
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "8ace70168e38743b8e86310c583564982c04978f4b93196d6ba911805c60c933", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8ace70168e38743b8e86310c583564982c04978f4b93196d6ba911805c60c933", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8ace70168e38743b8e86310c583564982c04978f4b93196d6ba911805c60c933", kill_on_drop: false }`
[INFO] [stdout] 8ace70168e38743b8e86310c583564982c04978f4b93196d6ba911805c60c933
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] 95abddaf015f5857aa1e459392572f9a14d4938c524329575a53828f4eb55b87
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "95abddaf015f5857aa1e459392572f9a14d4938c524329575a53828f4eb55b87", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.36
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.86
[INFO] [stderr]    Compiling serde_derive v1.0.136
[INFO] [stderr]    Compiling crc32fast v1.3.2
[INFO] [stderr]     Checking rle-decode-fast v1.0.3
[INFO] [stderr]    Compiling anyhow v1.0.55
[INFO] [stderr]    Compiling serde v1.0.136
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]     Checking adler32 v1.2.0
[INFO] [stderr]     Checking md5 v0.7.0
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]     Checking bytestream v0.4.1
[INFO] [stderr]     Checking libflate_lz77 v1.1.0
[INFO] [stderr]     Checking libflate v1.1.2
[INFO] [stderr]    Compiling quote v1.0.15
[INFO] [stderr]    Compiling num-derive v0.3.3
[INFO] [stderr]  Documenting ddcore-rs v0.3.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(io_safety)]
[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 `ddcore-rs`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2021 --crate-type lib --crate-name ddcore_rs 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=f4f4ef6fb8089432 -L dependency=/opt/rustwide/target/debug/deps --extern anyhow=/opt/rustwide/target/debug/deps/libanyhow-8e0a0fa7e945ca6a.rmeta --extern bytestream=/opt/rustwide/target/debug/deps/libbytestream-fac3c814420a8198.rmeta --extern libflate=/opt/rustwide/target/debug/deps/liblibflate-c0431962450e8519.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-9bc12257f57dd5ae.rmeta --extern md5=/opt/rustwide/target/debug/deps/libmd5-05cdc6da942a1386.rmeta --extern num_derive=/opt/rustwide/target/debug/deps/libnum_derive-be54927750eb1009.so --extern num_traits=/opt/rustwide/target/debug/deps/libnum_traits-1f9ec30a37ab6eb2.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-73836f432635c4c6.rmeta --cap-lints=warn --crate-version 0.3.0` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "95abddaf015f5857aa1e459392572f9a14d4938c524329575a53828f4eb55b87", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "95abddaf015f5857aa1e459392572f9a14d4938c524329575a53828f4eb55b87", kill_on_drop: false }`
[INFO] [stdout] 95abddaf015f5857aa1e459392572f9a14d4938c524329575a53828f4eb55b87