[INFO] fetching crate mutator 0.1.0...
[INFO] documenting mutator-0.1.0 against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] extracting crate mutator 0.1.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate mutator 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 mutator 0.1.0
[INFO] finished tweaking crates.io crate mutator 0.1.0
[INFO] tweaked toml for crates.io crate mutator 0.1.0 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] [stdout] 061945a85504d0e85a9c031493ec3ed464fa7d00c019dd2b45b07665362e989d
[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" "061945a85504d0e85a9c031493ec3ed464fa7d00c019dd2b45b07665362e989d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "061945a85504d0e85a9c031493ec3ed464fa7d00c019dd2b45b07665362e989d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "061945a85504d0e85a9c031493ec3ed464fa7d00c019dd2b45b07665362e989d", kill_on_drop: false }`
[INFO] [stdout] 061945a85504d0e85a9c031493ec3ed464fa7d00c019dd2b45b07665362e989d
[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] 3cca767fd5fbff2a974e51a0637f4ddd76c479bbdc145f5a9b7cc86adb25a694
[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" "3cca767fd5fbff2a974e51a0637f4ddd76c479bbdc145f5a9b7cc86adb25a694", kill_on_drop: false }`
[INFO] [stderr]  Documenting mutator v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.45s
[INFO] running `Command { std: "docker" "inspect" "3cca767fd5fbff2a974e51a0637f4ddd76c479bbdc145f5a9b7cc86adb25a694", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3cca767fd5fbff2a974e51a0637f4ddd76c479bbdc145f5a9b7cc86adb25a694", kill_on_drop: false }`
[INFO] [stdout] 3cca767fd5fbff2a974e51a0637f4ddd76c479bbdc145f5a9b7cc86adb25a694