[INFO] fetching crate un_algebra 0.9.0...
[INFO] documenting un_algebra-0.9.0 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate un_algebra 0.9.0 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate un_algebra 0.9.0 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 un_algebra 0.9.0
[INFO] finished tweaking crates.io crate un_algebra 0.9.0
[INFO] tweaked toml for crates.io crate un_algebra 0.9.0 written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate crates.io crate un_algebra 0.9.0 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] [stdout] 84801a54373917e91db9121745049a1d3dfcf073dd7374dee93eb258cc7fbc2e
[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" "84801a54373917e91db9121745049a1d3dfcf073dd7374dee93eb258cc7fbc2e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "84801a54373917e91db9121745049a1d3dfcf073dd7374dee93eb258cc7fbc2e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "84801a54373917e91db9121745049a1d3dfcf073dd7374dee93eb258cc7fbc2e", kill_on_drop: false }`
[INFO] [stdout] 84801a54373917e91db9121745049a1d3dfcf073dd7374dee93eb258cc7fbc2e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] cb39724a44b8589d6e532dce0a765aff19584a94c0f3f2111e20adaf9ffd9637
[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" "cb39724a44b8589d6e532dce0a765aff19584a94c0f3f2111e20adaf9ffd9637", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling byteorder v1.3.2
[INFO] [stderr]     Checking bit-vec v0.5.1
[INFO] [stderr]     Checking regex-syntax v0.6.12
[INFO] [stderr]    Compiling num-traits v0.2.10
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]     Checking wait-timeout v0.2.0
[INFO] [stderr]    Compiling proptest-derive v0.1.2
[INFO] [stderr]     Checking tempfile v3.1.0
[INFO] [stderr]     Checking bit-set v0.5.1
[INFO] [stderr]     Checking rusty-fork v0.2.2
[INFO] [stderr]     Checking num-integer v0.1.41
[INFO] [stderr]     Checking num-complex v0.2.3
[INFO] [stderr]     Checking num-bigint v0.2.3
[INFO] [stderr]     Checking num-iter v0.1.39
[INFO] [stderr]     Checking proptest v0.9.4
[INFO] [stderr]     Checking num-rational v0.2.2
[INFO] [stderr]     Checking num v0.2.0
[INFO] [stderr]  Documenting un_algebra v0.9.0 (/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(external_doc)]
[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 `un_algebra`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name un_algebra src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern num=/opt/rustwide/target/debug/deps/libnum-37bfa6c80311b388.rmeta --extern proptest=/opt/rustwide/target/debug/deps/libproptest-bafa3abe4436cd4e.rmeta --extern proptest_derive=/opt/rustwide/target/debug/deps/libproptest_derive-f1207b8fd2d9f52c.so --cap-lints=warn` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "cb39724a44b8589d6e532dce0a765aff19584a94c0f3f2111e20adaf9ffd9637", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cb39724a44b8589d6e532dce0a765aff19584a94c0f3f2111e20adaf9ffd9637", kill_on_drop: false }`
[INFO] [stdout] cb39724a44b8589d6e532dce0a765aff19584a94c0f3f2111e20adaf9ffd9637