[INFO] fetching crate c_rs 0.1.9...
[INFO] documenting c_rs-0.1.9 against 1.61.0 for beta-1.62-rustdoc-1
[INFO] extracting crate c_rs 0.1.9 into /workspace/builds/worker-46/source
[INFO] validating manifest of crates.io crate c_rs 0.1.9 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 c_rs 0.1.9
[INFO] finished tweaking crates.io crate c_rs 0.1.9
[INFO] tweaked toml for crates.io crate c_rs 0.1.9 written to /workspace/builds/worker-46/source/Cargo.toml
[INFO] crate crates.io crate c_rs 0.1.9 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]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded syntex_pos v0.42.0
[INFO] [stderr]   Downloaded syntex_errors v0.42.0
[INFO] [stderr]   Downloaded syntex_syntax v0.42.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/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] 615ae5d92fa5d0d0011dc8400d511fee2768e14d1e8c900d30c5af4ac219548e
[INFO] running `Command { std: "docker" "start" "-a" "615ae5d92fa5d0d0011dc8400d511fee2768e14d1e8c900d30c5af4ac219548e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "615ae5d92fa5d0d0011dc8400d511fee2768e14d1e8c900d30c5af4ac219548e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "615ae5d92fa5d0d0011dc8400d511fee2768e14d1e8c900d30c5af4ac219548e", kill_on_drop: false }`
[INFO] [stdout] 615ae5d92fa5d0d0011dc8400d511fee2768e14d1e8c900d30c5af4ac219548e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-46/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] e2658439d11a0904fde8e36541de386ae724cd13542d03acd332b45f6396cd0d
[INFO] running `Command { std: "docker" "start" "-a" "e2658439d11a0904fde8e36541de386ae724cd13542d03acd332b45f6396cd0d", kill_on_drop: false }`
[INFO] [stderr]    Compiling log v0.4.17
[INFO] [stderr]    Compiling libc v0.2.125
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking rustc-serialize v0.3.24
[INFO] [stderr]     Checking unicode-xid v0.0.3
[INFO] [stderr]     Checking term v0.4.6
[INFO] [stderr]     Checking log v0.3.9
[INFO] [stderr]     Checking syntex_pos v0.42.0
[INFO] [stderr]     Checking syntex_errors v0.42.0
[INFO] [stderr]  Documenting c_rs v0.1.9 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(core_ffi_c)]
[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:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(slice_internals)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 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 `c_rs`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name c_rs src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --document-private-items -C metadata=1cf8fda2b4bf7f73 -L dependency=/opt/rustwide/target/debug/deps --extern syntex_errors=/opt/rustwide/target/debug/deps/libsyntex_errors-2b2489a92cdd10a8.rmeta --extern syntex_pos=/opt/rustwide/target/debug/deps/libsyntex_pos-85df821bbee10495.rmeta --cap-lints=warn --crate-version 0.1.9` (exit status: 1)
[INFO] running `Command { std: "docker" "inspect" "e2658439d11a0904fde8e36541de386ae724cd13542d03acd332b45f6396cd0d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e2658439d11a0904fde8e36541de386ae724cd13542d03acd332b45f6396cd0d", kill_on_drop: false }`
[INFO] [stdout] e2658439d11a0904fde8e36541de386ae724cd13542d03acd332b45f6396cd0d