[INFO] cloning repository https://github.com/VaclavStebra/rust-book-references-and-borrowing
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/VaclavStebra/rust-book-references-and-borrowing" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FVaclavStebra%2Frust-book-references-and-borrowing"`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FVaclavStebra%2Frust-book-references-and-borrowing'...
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 6a69d6a3a909d36b8b69bc865641a6b3053066d0
[INFO] checking VaclavStebra/rust-book-references-and-borrowing against master#b61e69433951e31f7bd746e22f516a48ad41623b for prs-64470-and-65389
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FVaclavStebra%2Frust-book-references-and-borrowing" "/workspace/builds/worker-1/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/VaclavStebra/rust-book-references-and-borrowing on toolchain b61e69433951e31f7bd746e22f516a48ad41623b
[INFO] running `"/workspace/cargo-home/bin/cargo" "+b61e69433951e31f7bd746e22f516a48ad41623b" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/VaclavStebra/rust-book-references-and-borrowing
[INFO] finished tweaking git repo https://github.com/VaclavStebra/rust-book-references-and-borrowing
[INFO] tweaked toml for git repo https://github.com/VaclavStebra/rust-book-references-and-borrowing written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/VaclavStebra/rust-book-references-and-borrowing already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+b61e69433951e31f7bd746e22f516a48ad41623b" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+b61e69433951e31f7bd746e22f516a48ad41623b" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] caa9049d2f5f193e86e910aa5d1c7eb799248d646489bb321e378bcd71def924
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "caa9049d2f5f193e86e910aa5d1c7eb799248d646489bb321e378bcd71def924"`
[INFO] [stderr]     Checking rust-book-references-and-borrowing v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `r1`
[INFO] [stderr]   --> src/main.rs:20:9
[INFO] [stderr]    |
[INFO] [stderr] 20 |     let r1 = &mut s2;
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_r1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `r1`
[INFO] [stderr]   --> src/main.rs:20:9
[INFO] [stderr]    |
[INFO] [stderr] 20 |     let r1 = &mut s2;
[INFO] [stderr]    |         ^^ help: consider prefixing with an underscore: `_r1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.13s
[INFO] running `"docker" "inspect" "caa9049d2f5f193e86e910aa5d1c7eb799248d646489bb321e378bcd71def924"`
[INFO] running `"docker" "rm" "-f" "caa9049d2f5f193e86e910aa5d1c7eb799248d646489bb321e378bcd71def924"`
[INFO] [stdout] caa9049d2f5f193e86e910aa5d1c7eb799248d646489bb321e378bcd71def924