[INFO] fetching crate pack_2048 0.4.4...
[INFO] checking pack_2048-0.4.4 against master#90442458ac46b1d5eed752c316da25450f67285b for pr-81477
[INFO] extracting crate pack_2048 0.4.4 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate pack_2048 0.4.4 on toolchain 90442458ac46b1d5eed752c316da25450f67285b
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate pack_2048 0.4.4
[INFO] finished tweaking crates.io crate pack_2048 0.4.4
[INFO] tweaked toml for crates.io crate pack_2048 0.4.4 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "fetch" "--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "metadata" "--no-deps" "--format-version=1", 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] 8906d92d2276fc05c8f31e09b0a623ec88f4b8a0e8793ce4e55737052ccebb1f
[INFO] running `Command { std: "docker" "start" "-a" "8906d92d2276fc05c8f31e09b0a623ec88f4b8a0e8793ce4e55737052ccebb1f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8906d92d2276fc05c8f31e09b0a623ec88f4b8a0e8793ce4e55737052ccebb1f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8906d92d2276fc05c8f31e09b0a623ec88f4b8a0e8793ce4e55737052ccebb1f", kill_on_drop: false }`
[INFO] [stdout] 8906d92d2276fc05c8f31e09b0a623ec88f4b8a0e8793ce4e55737052ccebb1f
[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" "RUSTFLAGS=--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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c914e566c63bfc88fd09db2dcd3582715d4c25dc12395f79afb761112c8b605a
[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" "c914e566c63bfc88fd09db2dcd3582715d4c25dc12395f79afb761112c8b605a", kill_on_drop: false }`
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stderr]     Checking termion v1.5.6
[INFO] [stderr]     Checking pack_2048 v0.4.4 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:105:13
[INFO] [stdout]     |
[INFO] [stdout] 105 |         for mut row in &mut board.iter_mut() {
[INFO] [stdout]     |             ----^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:165:13
[INFO] [stdout]     |
[INFO] [stdout] 165 |         for mut row in &mut board.iter_mut() {
[INFO] [stdout]     |             ----^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:105:13
[INFO] [stdout]     |
[INFO] [stdout] 105 |         for mut row in &mut board.iter_mut() {
[INFO] [stdout]     |             ----^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:165:13
[INFO] [stdout]     |
[INFO] [stdout] 165 |         for mut row in &mut board.iter_mut() {
[INFO] [stdout]     |             ----^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.72s
[INFO] running `Command { std: "docker" "inspect" "c914e566c63bfc88fd09db2dcd3582715d4c25dc12395f79afb761112c8b605a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c914e566c63bfc88fd09db2dcd3582715d4c25dc12395f79afb761112c8b605a", kill_on_drop: false }`
[INFO] [stdout] c914e566c63bfc88fd09db2dcd3582715d4c25dc12395f79afb761112c8b605a