[INFO] cloning repository https://github.com/learn-you-a-rust/return_values
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/learn-you-a-rust/return_values" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Freturn_values", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Freturn_values'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 4195fe7f63dbb5786bb5d2e2a6781a3ef7d6f6c7
[INFO] checking learn-you-a-rust/return_values against master#ff0b4b6091a75ad840035a991426c8bc9fbd93bb for pr-117673
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Freturn_values" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/learn-you-a-rust/return_values on toolchain ff0b4b6091a75ad840035a991426c8bc9fbd93bb
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ff0b4b6091a75ad840035a991426c8bc9fbd93bb" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/learn-you-a-rust/return_values
[INFO] finished tweaking git repo https://github.com/learn-you-a-rust/return_values
[INFO] tweaked toml for git repo https://github.com/learn-you-a-rust/return_values written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/learn-you-a-rust/return_values already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ff0b4b6091a75ad840035a991426c8bc9fbd93bb" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[ERROR] this task or one of its parent failed!
[ERROR] no output for 300 seconds
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.
[INFO] checking learn-you-a-rust/return_values against try#9ee647322baa27cc6bb1a95b4595bad94b334fcf for pr-117673
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Freturn_values" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/learn-you-a-rust/return_values on toolchain 9ee647322baa27cc6bb1a95b4595bad94b334fcf
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9ee647322baa27cc6bb1a95b4595bad94b334fcf" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/learn-you-a-rust/return_values
[INFO] finished tweaking git repo https://github.com/learn-you-a-rust/return_values
[INFO] tweaked toml for git repo https://github.com/learn-you-a-rust/return_values written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/learn-you-a-rust/return_values already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9ee647322baa27cc6bb1a95b4595bad94b334fcf" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[INFO] checking learn-you-a-rust/return_values against try#9ee647322baa27cc6bb1a95b4595bad94b334fcf for pr-117673
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flearn-you-a-rust%2Freturn_values" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/learn-you-a-rust/return_values on toolchain 9ee647322baa27cc6bb1a95b4595bad94b334fcf
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9ee647322baa27cc6bb1a95b4595bad94b334fcf" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/learn-you-a-rust/return_values
[INFO] finished tweaking git repo https://github.com/learn-you-a-rust/return_values
[INFO] tweaked toml for git repo https://github.com/learn-you-a-rust/return_values written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/learn-you-a-rust/return_values already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9ee647322baa27cc6bb1a95b4595bad94b334fcf" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:0c7e0e8312ad82a1bed3696438480b7da990d348377d3754e1cd95b06a8a36c7" "/opt/rustwide/cargo-home/bin/cargo" "+9ee647322baa27cc6bb1a95b4595bad94b334fcf" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] efdad4fbea849fcbf7b4d8aebfe41506d1c5793938300601629d140bbbb6bb20
[INFO] running `Command { std: "docker" "start" "-a" "efdad4fbea849fcbf7b4d8aebfe41506d1c5793938300601629d140bbbb6bb20", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "efdad4fbea849fcbf7b4d8aebfe41506d1c5793938300601629d140bbbb6bb20", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "efdad4fbea849fcbf7b4d8aebfe41506d1c5793938300601629d140bbbb6bb20", kill_on_drop: false }`
[INFO] [stdout] efdad4fbea849fcbf7b4d8aebfe41506d1c5793938300601629d140bbbb6bb20
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:0c7e0e8312ad82a1bed3696438480b7da990d348377d3754e1cd95b06a8a36c7" "/opt/rustwide/cargo-home/bin/cargo" "+9ee647322baa27cc6bb1a95b4595bad94b334fcf" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a37eeae973ba0f73981e4a9d579176d0c363943d28da6dda581934a941f356e6
[INFO] running `Command { std: "docker" "start" "-a" "a37eeae973ba0f73981e4a9d579176d0c363943d28da6dda581934a941f356e6", kill_on_drop: false }`
[INFO] [stderr]     Checking return_values v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.07s
[INFO] running `Command { std: "docker" "inspect" "a37eeae973ba0f73981e4a9d579176d0c363943d28da6dda581934a941f356e6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a37eeae973ba0f73981e4a9d579176d0c363943d28da6dda581934a941f356e6", kill_on_drop: false }`
[INFO] [stdout] a37eeae973ba0f73981e4a9d579176d0c363943d28da6dda581934a941f356e6