[INFO] fetching crate ss-trees 0.1.1...
[INFO] documenting ss-trees-0.1.1 against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] extracting crate ss-trees 0.1.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate ss-trees 0.1.1 on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate ss-trees 0.1.1
[INFO] finished tweaking crates.io crate ss-trees 0.1.1
[INFO] tweaked toml for crates.io crate ss-trees 0.1.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "+beta-2020-08-29" "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] 121372c99d3034a124c78a24405b751fdb955451b5568dd452fde3537b852022
[INFO] running `Command { std: "docker" "start" "-a" "121372c99d3034a124c78a24405b751fdb955451b5568dd452fde3537b852022", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "121372c99d3034a124c78a24405b751fdb955451b5568dd452fde3537b852022", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "121372c99d3034a124c78a24405b751fdb955451b5568dd452fde3537b852022", kill_on_drop: false }`
[INFO] [stdout] 121372c99d3034a124c78a24405b751fdb955451b5568dd452fde3537b852022
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0a5f823743f9e623b6fa3b243fd80de6ad5533ef77aa8fcec05329441c0343b8
[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" "0a5f823743f9e623b6fa3b243fd80de6ad5533ef77aa8fcec05329441c0343b8", kill_on_drop: false }`
[INFO] [stderr]    Compiling wasm-bindgen-shared v0.2.67
[INFO] [stderr]    Compiling bumpalo v3.4.0
[INFO] [stderr]     Checking scopeguard v0.3.3
[INFO] [stderr]    Compiling wasm-bindgen v0.2.67
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand_jitter v0.1.4
[INFO] [stderr]     Checking itertools v0.8.2
[INFO] [stderr]    Compiling parking_lot_core v0.4.0
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]     Checking rand_pcg v0.1.2
[INFO] [stderr]     Checking serde v1.0.115
[INFO] [stderr]     Checking lock_api v0.1.5
[INFO] [stderr]     Checking rand_isaac v0.1.1
[INFO] [stderr]     Checking rand_hc v0.1.0
[INFO] [stderr]     Checking rand_chacha v0.1.1
[INFO] [stderr]     Checking rand_xorshift v0.1.1
[INFO] [stderr]     Checking rand v0.6.5
[INFO] [stderr]    Compiling wasm-bindgen-backend v0.2.67
[INFO] [stderr]     Checking parking_lot v0.7.1
[INFO] [stderr]    Compiling wasm-bindgen-macro-support v0.2.67
[INFO] [stderr]     Checking once_cell v0.1.8
[INFO] [stderr]     Checking cached v0.8.1
[INFO] [stderr]    Compiling wasm-bindgen-macro v0.2.67
[INFO] [stderr]     Checking serde_json v1.0.57
[INFO] [stderr]     Checking js-sys v0.3.44
[INFO] [stderr]     Checking web-sys v0.3.44
[INFO] [stderr]     Checking ss-web-utils v0.1.1
[INFO] [stderr]  Documenting ss-trees v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(vec_remove_item)]
[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 `ss-trees`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name ss_trees 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 either=/opt/rustwide/target/debug/deps/libeither-e5928af0be8c0bf6.rmeta --extern itertools=/opt/rustwide/target/debug/deps/libitertools-e6357416dc20e093.rmeta --extern ss_web_utils=/opt/rustwide/target/debug/deps/libss_web_utils-880bd7e43e15aa36.rmeta --cap-lints=warn --crate-version 0.1.1` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "0a5f823743f9e623b6fa3b243fd80de6ad5533ef77aa8fcec05329441c0343b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0a5f823743f9e623b6fa3b243fd80de6ad5533ef77aa8fcec05329441c0343b8", kill_on_drop: false }`
[INFO] [stdout] 0a5f823743f9e623b6fa3b243fd80de6ad5533ef77aa8fcec05329441c0343b8