[INFO] fetching crate slabmalloc 0.7.0...
[INFO] documenting slabmalloc-0.7.0 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate slabmalloc 0.7.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate slabmalloc 0.7.0 on toolchain 1.46.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate slabmalloc 0.7.0
[INFO] finished tweaking crates.io crate slabmalloc 0.7.0
[INFO] tweaked toml for crates.io crate slabmalloc 0.7.0 written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate crates.io crate slabmalloc 0.7.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 0a808f4d4e367ab9d0c9c25537f7b13ca003c35fa6de5f3cf5202c45ea577422
[INFO] running `Command { std: "docker" "start" "-a" "0a808f4d4e367ab9d0c9c25537f7b13ca003c35fa6de5f3cf5202c45ea577422", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0a808f4d4e367ab9d0c9c25537f7b13ca003c35fa6de5f3cf5202c45ea577422", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0a808f4d4e367ab9d0c9c25537f7b13ca003c35fa6de5f3cf5202c45ea577422", kill_on_drop: false }`
[INFO] [stdout] 0a808f4d4e367ab9d0c9c25537f7b13ca003c35fa6de5f3cf5202c45ea577422
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e26b7ff89ef10da539741ad8a687aa86a8eea472213885e2a8656e8dc12fb691
[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" "e26b7ff89ef10da539741ad8a687aa86a8eea472213885e2a8656e8dc12fb691", kill_on_drop: false }`
[INFO] [stderr]  Documenting slabmalloc v0.7.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:21:35
[INFO] [stdout]    |
[INFO] [stdout] 21 | #![cfg_attr(feature = "unstable", feature(const_fn))]
[INFO] [stdout]    |                                   ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[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 `slabmalloc`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name slabmalloc src/lib.rs -o /opt/rustwide/target/doc --cfg 'feature="default"' --cfg 'feature="unstable"' --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern log=/opt/rustwide/target/debug/deps/liblog-f96ba0118540bef9.rmeta --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "e26b7ff89ef10da539741ad8a687aa86a8eea472213885e2a8656e8dc12fb691", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e26b7ff89ef10da539741ad8a687aa86a8eea472213885e2a8656e8dc12fb691", kill_on_drop: false }`
[INFO] [stdout] e26b7ff89ef10da539741ad8a687aa86a8eea472213885e2a8656e8dc12fb691