[INFO] cloning repository https://github.com/HappyDustbunny/fern
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/HappyDustbunny/fern" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FHappyDustbunny%2Ffern", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FHappyDustbunny%2Ffern'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c1269b509f8759110724eb87fadacd4081d82dae
[INFO] documenting HappyDustbunny/fern against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FHappyDustbunny%2Ffern" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/HappyDustbunny/fern 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 git repo https://github.com/HappyDustbunny/fern
[INFO] finished tweaking git repo https://github.com/HappyDustbunny/fern
[INFO] tweaked toml for git repo https://github.com/HappyDustbunny/fern written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/HappyDustbunny/fern already has a lockfile, it will not be regenerated
[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] [stdout] 4b93c3d3073cb70548925617d58983e098af9b6ccf226f69e4b249246fbeb544
[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" "4b93c3d3073cb70548925617d58983e098af9b6ccf226f69e4b249246fbeb544", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4b93c3d3073cb70548925617d58983e098af9b6ccf226f69e4b249246fbeb544", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4b93c3d3073cb70548925617d58983e098af9b6ccf226f69e4b249246fbeb544", kill_on_drop: false }`
[INFO] [stdout] 4b93c3d3073cb70548925617d58983e098af9b6ccf226f69e4b249246fbeb544
[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] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] fef162b1ce2ce8589e008fce72daccd2f059e6ce2e61c06ad70d9b33491ff78f
[INFO] running `Command { std: "docker" "start" "-a" "fef162b1ce2ce8589e008fce72daccd2f059e6ce2e61c06ad70d9b33491ff78f", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.60
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling serde v1.0.98
[INFO] [stderr]    Compiling vulkano v0.13.0
[INFO] [stderr]     Checking vk-sys v0.4.0
[INFO] [stderr]     Checking half v1.3.0
[INFO] [stderr]     Checking instant v0.1.1
[INFO] [stderr]    Compiling cgmath v0.16.1
[INFO] [stderr]     Checking conrod_winit v0.66.0
[INFO] [stderr]    Compiling libloading v0.5.2
[INFO] [stderr]    Compiling cmake v0.1.41
[INFO] [stderr]    Compiling num-complex v0.2.3
[INFO] [stderr]     Checking inflate v0.3.4
[INFO] [stderr]    Compiling parking_lot_core v0.5.0
[INFO] [stderr]    Compiling parking_lot v0.8.0
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]     Checking num-integer v0.1.41
[INFO] [stderr]     Checking ordered-float v1.0.2
[INFO] [stderr]     Checking approx v0.3.2
[INFO] [stderr]     Checking line_drawing v0.7.0
[INFO] [stderr]     Checking num-traits v0.1.43
[INFO] [stderr]     Checking pennereq v0.3.0
[INFO] [stderr]     Checking enum_primitive v0.1.1
[INFO] [stderr]    Compiling palette_derive v0.4.1
[INFO] [stderr]     Checking crossbeam-deque v0.6.3
[INFO] [stderr]     Checking crossbeam v0.7.2
[INFO] [stderr]    Compiling shaderc-sys v0.5.1
[INFO] [stderr]     Checking dlib v0.4.1
[INFO] [stderr]     Checking num-iter v0.1.39
[INFO] [stderr]     Checking num-bigint v0.2.2
[INFO] [stderr]     Checking num-rational v0.1.42
[INFO] [stderr]     Checking wayland-sys v0.21.13
[INFO] [stderr]     Checking png v0.11.0
[INFO] [stderr]     Checking png v0.14.1
[INFO] [stderr]     Checking num_cpus v1.10.1
[INFO] [stderr]     Checking nix v0.14.1
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking shared_library v0.1.9
[INFO] [stderr]     Checking getrandom v0.1.8
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking memmap v0.7.0
[INFO] [stderr]     Checking x11-dl v2.18.3
[INFO] [stderr]     Checking rusttype v0.7.7
[INFO] [stderr]     Checking rayon-core v1.5.0
[INFO] [stderr]     Checking rand v0.6.5
[INFO] [stderr]     Checking rand_core v0.5.0
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rayon v1.1.0
[INFO] [stderr]     Checking rand v0.7.0
[INFO] [stderr]     Checking andrew v0.2.1
[INFO] [stderr]     Checking num-rational v0.2.2
[INFO] [stderr]     Checking rand v0.3.23
[INFO] [stderr]     Checking num v0.2.0
[INFO] [stderr] error: could not compile `syn`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustc --crate-name syn /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/syn-0.15.44/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type lib --emit=dep-info,metadata,link -Cembed-bitcode=no -C debuginfo=2 --cfg 'feature="clone-impls"' --cfg 'feature="default"' --cfg 'feature="derive"' --cfg 'feature="extra-traits"' --cfg 'feature="full"' --cfg 'feature="parsing"' --cfg 'feature="printing"' --cfg 'feature="proc-macro"' --cfg 'feature="quote"' --cfg 'feature="visit"' -C metadata=b3468758892a6b1b -C extra-filename=-b3468758892a6b1b --out-dir /opt/rustwide/target/debug/deps -L dependency=/opt/rustwide/target/debug/deps --extern proc_macro2=/opt/rustwide/target/debug/deps/libproc_macro2-1c8cd06d03ec2d01.rmeta --extern quote=/opt/rustwide/target/debug/deps/libquote-179b18ceb2cbc452.rmeta --extern unicode_xid=/opt/rustwide/target/debug/deps/libunicode_xid-de12218e15042935.rmeta --cap-lints allow --cfg syn_can_match_trailing_dollar --cfg syn_can_use_thread_id --cfg syn_can_use_associated_constants --cfg syn_can_call_macro_by_path --cfg syn_disable_nightly_tests` (signal: 9, SIGKILL: kill)
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] The following warnings were emitted during compilation:
[INFO] [stderr] 
[INFO] [stderr] warning: Checking for system installed libraries.  Use --features = build-from-source to disable this behavior
[INFO] [stderr] warning: Pre-built library not found.  Falling back to from-source build
[INFO] [stderr] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "fef162b1ce2ce8589e008fce72daccd2f059e6ce2e61c06ad70d9b33491ff78f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fef162b1ce2ce8589e008fce72daccd2f059e6ce2e61c06ad70d9b33491ff78f", kill_on_drop: false }`
[INFO] [stdout] fef162b1ce2ce8589e008fce72daccd2f059e6ce2e61c06ad70d9b33491ff78f