[INFO] fetching crate credibility 0.1.3...
[INFO] documenting credibility-0.1.3 against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] extracting crate credibility 0.1.3 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate credibility 0.1.3 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 credibility 0.1.3
[INFO] finished tweaking crates.io crate credibility 0.1.3
[INFO] tweaked toml for crates.io crate credibility 0.1.3 written to /workspace/builds/worker-6/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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 6076d7e5045f402aaa10cf25a0a2195363c1fbc4c8cea07e636962d93f078e07
[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" "6076d7e5045f402aaa10cf25a0a2195363c1fbc4c8cea07e636962d93f078e07", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6076d7e5045f402aaa10cf25a0a2195363c1fbc4c8cea07e636962d93f078e07", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6076d7e5045f402aaa10cf25a0a2195363c1fbc4c8cea07e636962d93f078e07", kill_on_drop: false }`
[INFO] [stdout] 6076d7e5045f402aaa10cf25a0a2195363c1fbc4c8cea07e636962d93f078e07
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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] 675632464b7708ffeac7a658db8d3a07392cc79339d4fd67139a4674982cc661
[INFO] running `Command { std: "docker" "start" "-a" "675632464b7708ffeac7a658db8d3a07392cc79339d4fd67139a4674982cc661", kill_on_drop: false }`
[INFO] [stderr]     Checking backtrace v0.3.50
[INFO] [stderr]     Checking failure v0.1.8
[INFO] [stderr]  Documenting credibility v0.1.3 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.46s
[INFO] running `Command { std: "docker" "inspect" "675632464b7708ffeac7a658db8d3a07392cc79339d4fd67139a4674982cc661", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "675632464b7708ffeac7a658db8d3a07392cc79339d4fd67139a4674982cc661", kill_on_drop: false }`
[INFO] [stdout] 675632464b7708ffeac7a658db8d3a07392cc79339d4fd67139a4674982cc661