[INFO] fetching crate taikai 0.1.0...
[INFO] documenting taikai-0.1.0 against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] extracting crate taikai 0.1.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate taikai 0.1.0 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 taikai 0.1.0
[INFO] finished tweaking crates.io crate taikai 0.1.0
[INFO] tweaked toml for crates.io crate taikai 0.1.0 written to /workspace/builds/worker-9/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-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" "+beta-2020-08-29" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 30a6ff00113c280f186e6c09b319a5363a49fe750ed0d15fcea427af45443a10
[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" "30a6ff00113c280f186e6c09b319a5363a49fe750ed0d15fcea427af45443a10", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "30a6ff00113c280f186e6c09b319a5363a49fe750ed0d15fcea427af45443a10", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "30a6ff00113c280f186e6c09b319a5363a49fe750ed0d15fcea427af45443a10", kill_on_drop: false }`
[INFO] [stdout] 30a6ff00113c280f186e6c09b319a5363a49fe750ed0d15fcea427af45443a10
[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" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 06e194e2ee44e0325151bef3e8496d776f0f820b0030b9bdd451f9450e33630e
[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" "06e194e2ee44e0325151bef3e8496d776f0f820b0030b9bdd451f9450e33630e", kill_on_drop: false }`
[INFO] [stderr]  Documenting taikai v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]  --> src/lib.rs:4:12
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(custom_attribute)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^ feature has been removed
[INFO] [stdout]   |
[INFO] [stdout]   = note: removed in favor of `#![register_tool]` and `#![register_attr]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(bind_by_move_pattern_guards)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(custom_attribute)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(proc_macro_span)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #![feature(try_blocks)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 6 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0557.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: Could not document `taikai`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type proc-macro --crate-name taikai 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 encoding_rs=/opt/rustwide/target/debug/deps/libencoding_rs-acfa9bdd28dd5dfb.rmeta --extern failure=/opt/rustwide/target/debug/deps/libfailure-3d0ba9b30d5da469.rmeta --extern heck=/opt/rustwide/target/debug/deps/libheck-dca7a1fa867a47e1.rmeta --extern itertools=/opt/rustwide/target/debug/deps/libitertools-433d1b037a7098c7.rmeta --extern proc_macro2=/opt/rustwide/target/debug/deps/libproc_macro2-e2b55f3fa9b89984.rmeta --extern quote=/opt/rustwide/target/debug/deps/libquote-252ac74022158045.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-ec5e695d7e4b5284.rmeta --extern serde_derive=/opt/rustwide/target/debug/deps/libserde_derive-3a89c57880b62507.so --extern serde_yaml=/opt/rustwide/target/debug/deps/libserde_yaml-957c6d830cc89b49.rmeta --extern syn=/opt/rustwide/target/debug/deps/libsyn-1021cd05e19316e0.rmeta --extern proc_macro --cap-lints=warn --crate-version 0.1.0` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "06e194e2ee44e0325151bef3e8496d776f0f820b0030b9bdd451f9450e33630e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "06e194e2ee44e0325151bef3e8496d776f0f820b0030b9bdd451f9450e33630e", kill_on_drop: false }`
[INFO] [stdout] 06e194e2ee44e0325151bef3e8496d776f0f820b0030b9bdd451f9450e33630e