[INFO] fetching crate guidon 0.2.8...
[INFO] documenting guidon-0.2.8 against beta-2020-10-09 for beta-1.48-rustdoc-1
[INFO] extracting crate guidon 0.2.8 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate guidon 0.2.8 on toolchain beta-2020-10-09
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-10-09" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate guidon 0.2.8
[INFO] finished tweaking crates.io crate guidon 0.2.8
[INFO] tweaked toml for crates.io crate guidon 0.2.8 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-10-09" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-10-09" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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-2020-10-09" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b8bb432c21a3bd6b3b9aa77d7017ab948ab978bb4d682bd6b6cf6aec01214988
[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" "b8bb432c21a3bd6b3b9aa77d7017ab948ab978bb4d682bd6b6cf6aec01214988", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b8bb432c21a3bd6b3b9aa77d7017ab948ab978bb4d682bd6b6cf6aec01214988", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b8bb432c21a3bd6b3b9aa77d7017ab948ab978bb4d682bd6b6cf6aec01214988", kill_on_drop: false }`
[INFO] [stdout] b8bb432c21a3bd6b3b9aa77d7017ab948ab978bb4d682bd6b6cf6aec01214988
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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-2020-10-09" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d0e13260d3dc1b0cf52b416b9b7f8c19544c325ce7bc74026d71b93cace60e86
[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" "d0e13260d3dc1b0cf52b416b9b7f8c19544c325ce7bc74026d71b93cace60e86", kill_on_drop: false }`
[INFO] [stderr]     Checking toml v0.5.7
[INFO] [stderr]    Compiling jobserver v0.1.21
[INFO] [stderr]    Compiling darling_core v0.10.2
[INFO] [stderr]    Compiling pest_generator v2.1.3
[INFO] [stderr]    Compiling cc v1.0.61
[INFO] [stderr]    Compiling openssl-sys v0.9.58
[INFO] [stderr]    Compiling libz-sys v1.1.2
[INFO] [stderr]    Compiling libssh2-sys v0.2.19
[INFO] [stderr]    Compiling libgit2-sys v0.12.14+1.1.0
[INFO] [stderr]    Compiling pest_derive v2.1.0
[INFO] [stderr]    Compiling darling_macro v0.10.2
[INFO] [stderr]     Checking handlebars v3.5.0
[INFO] [stderr]    Compiling darling v0.10.2
[INFO] [stderr]    Compiling derive_builder_core v0.9.0
[INFO] [stderr]    Compiling derive_builder v0.9.0
[INFO] [stderr]     Checking git2 v0.13.12
[INFO] [stderr]  Documenting guidon v0.2.8 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(map_first_last)]
[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 `guidon`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name guidon src/lib.rs -o /opt/rustwide/target/doc --cfg 'feature="default"' --cfg 'feature="derive_builder"' --cfg 'feature="git"' --cfg 'feature="git2"' --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern derive_builder=/opt/rustwide/target/debug/deps/libderive_builder-9da462bd46b5177d.so --extern git2=/opt/rustwide/target/debug/deps/libgit2-de439a522f956458.rmeta --extern handlebars=/opt/rustwide/target/debug/deps/libhandlebars-f2e7b24ea7ef1c20.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-95a9d57e67df36ac.rmeta --extern serde=/opt/rustwide/target/debug/deps/libserde-206cfb4b5fe90396.rmeta --extern serde_derive=/opt/rustwide/target/debug/deps/libserde_derive-b9da2be819d4f187.so --extern toml=/opt/rustwide/target/debug/deps/libtoml-ac0ec9354b2ef8d1.rmeta --cap-lints=warn --crate-version 0.2.8` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "d0e13260d3dc1b0cf52b416b9b7f8c19544c325ce7bc74026d71b93cace60e86", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d0e13260d3dc1b0cf52b416b9b7f8c19544c325ce7bc74026d71b93cace60e86", kill_on_drop: false }`
[INFO] [stdout] d0e13260d3dc1b0cf52b416b9b7f8c19544c325ce7bc74026d71b93cace60e86
