[INFO] cloning repository https://github.com/ddavison/rust-exercises
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ddavison/rust-exercises" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fddavison%2Frust-exercises", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fddavison%2Frust-exercises'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] bd2c076cacf37fa15e38ff5bdd6aa871d161b343
[INFO] checking ddavison/rust-exercises against try#723ab942d877517caf445dafde0416803ef56501 for pr-143857
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fddavison%2Frust-exercises" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/ddavison/rust-exercises
[INFO] finished tweaking git repo https://github.com/ddavison/rust-exercises
[INFO] tweaked toml for git repo https://github.com/ddavison/rust-exercises written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/ddavison/rust-exercises on toolchain 723ab942d877517caf445dafde0416803ef56501
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+723ab942d877517caf445dafde0416803ef56501" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/ddavison/rust-exercises 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" "+723ab942d877517caf445dafde0416803ef56501" "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-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+723ab942d877517caf445dafde0416803ef56501" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 37ff001b21056748c254431507376ef4a179318923e7e28c2b9df0bd05cac326
[INFO] running `Command { std: "docker" "start" "-a" "37ff001b21056748c254431507376ef4a179318923e7e28c2b9df0bd05cac326", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "37ff001b21056748c254431507376ef4a179318923e7e28c2b9df0bd05cac326", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "37ff001b21056748c254431507376ef4a179318923e7e28c2b9df0bd05cac326", kill_on_drop: false }`
[INFO] [stdout] 37ff001b21056748c254431507376ef4a179318923e7e28c2b9df0bd05cac326
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+723ab942d877517caf445dafde0416803ef56501" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3244ca047eaa6f4415f4509aef894b498505ec94fd71cae125f127d88b3d8006
[INFO] running `Command { std: "docker" "start" "-a" "3244ca047eaa6f4415f4509aef894b498505ec94fd71cae125f127d88b3d8006", kill_on_drop: false }`
[INFO] [stderr]     Checking exercises v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]  --> src/main.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let b = true;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]  --> src/main.rs:4:9
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let b = true;
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.10s
[INFO] running `Command { std: "docker" "inspect" "3244ca047eaa6f4415f4509aef894b498505ec94fd71cae125f127d88b3d8006", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3244ca047eaa6f4415f4509aef894b498505ec94fd71cae125f127d88b3d8006", kill_on_drop: false }`
[INFO] [stdout] 3244ca047eaa6f4415f4509aef894b498505ec94fd71cae125f127d88b3d8006