[INFO] fetching crate r4 1.0.1...
[INFO] checking r4-1.0.1 against master#5e3f1b148db5bfa27fee52464ae1f5d34c49d77b for pr-75502
[INFO] extracting crate r4 1.0.1 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate r4 1.0.1 on toolchain 5e3f1b148db5bfa27fee52464ae1f5d34c49d77b
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate r4 1.0.1
[INFO] finished tweaking crates.io crate r4 1.0.1
[INFO] tweaked toml for crates.io crate r4 1.0.1 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cda505dce74779e93fc9861f3c53b9d7fadfd291de314f1787d3df27d484925d
[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" "cda505dce74779e93fc9861f3c53b9d7fadfd291de314f1787d3df27d484925d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cda505dce74779e93fc9861f3c53b9d7fadfd291de314f1787d3df27d484925d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cda505dce74779e93fc9861f3c53b9d7fadfd291de314f1787d3df27d484925d", kill_on_drop: false }`
[INFO] [stdout] cda505dce74779e93fc9861f3c53b9d7fadfd291de314f1787d3df27d484925d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+5e3f1b148db5bfa27fee52464ae1f5d34c49d77b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 78d19788ce429f33058e4a8bb0cde5a0af5ce2ffa9add78e17c94fa8cb89021b
[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" "78d19788ce429f33058e4a8bb0cde5a0af5ce2ffa9add78e17c94fa8cb89021b", kill_on_drop: false }`
[INFO] [stderr]     Checking r4 v1.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]    --> src/lib.rs:407:34
[INFO] [stdout]     |
[INFO] [stdout] 407 |                     iterate![for i in 0..4;
[INFO] [stdout]     |                                  ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/lib.rs:433:34
[INFO] [stdout]     |
[INFO] [stdout] 433 |                     iterate![for x in vs.iter();
[INFO] [stdout]     |                                  ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/lib.rs:443:34
[INFO] [stdout]     |
[INFO] [stdout] 443 |                     iterate![for x in vs.iter();
[INFO] [stdout]     |                                  ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/lib.rs:474:34
[INFO] [stdout]     |
[INFO] [stdout] 474 | ...                   let a = *x + 3;
[INFO] [stdout]     |                           ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]    --> src/lib.rs:489:34
[INFO] [stdout]     |
[INFO] [stdout] 489 | ...                   let a = *x + 3;
[INFO] [stdout]     |                           ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/lib.rs:506:34
[INFO] [stdout]     |
[INFO] [stdout] 506 | ...                   for y in vs.iter();
[INFO] [stdout]     |                           ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/lib.rs:522:34
[INFO] [stdout]     |
[INFO] [stdout] 522 | ...                   let x = *x + 1;
[INFO] [stdout]     |                           ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.36s
[INFO] running `Command { std: "docker" "inspect" "78d19788ce429f33058e4a8bb0cde5a0af5ce2ffa9add78e17c94fa8cb89021b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "78d19788ce429f33058e4a8bb0cde5a0af5ce2ffa9add78e17c94fa8cb89021b", kill_on_drop: false }`
[INFO] [stdout] 78d19788ce429f33058e4a8bb0cde5a0af5ce2ffa9add78e17c94fa8cb89021b