[INFO] fetching crate head_tail 0.1.0...
[INFO] testing head_tail-0.1.0 against try#dec9417b8611e34e787a3e4c37686b5131f9e5c5 for pr-154210-1
[INFO] extracting crate head_tail 0.1.0 into /workspace/builds/worker-4-tc2/source
[INFO] removed /workspace/builds/worker-4-tc2/source/rust-toolchain.toml
[INFO] started tweaking crates.io crate head_tail 0.1.0
[INFO] finished tweaking crates.io crate head_tail 0.1.0
[INFO] tweaked toml for crates.io crate head_tail 0.1.0 written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate head_tail 0.1.0 on toolchain dec9417b8611e34e787a3e4c37686b5131f9e5c5
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+dec9417b8611e34e787a3e4c37686b5131f9e5c5" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate head_tail 0.1.0 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" "+dec9417b8611e34e787a3e4c37686b5131f9e5c5" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+dec9417b8611e34e787a3e4c37686b5131f9e5c5" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 067deca687e40bc05b61d700c92fea8162ba92611d9f7026c1fa6a7304f1aeea
[INFO] running `Command { std: "docker" "start" "-a" "067deca687e40bc05b61d700c92fea8162ba92611d9f7026c1fa6a7304f1aeea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "067deca687e40bc05b61d700c92fea8162ba92611d9f7026c1fa6a7304f1aeea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "067deca687e40bc05b61d700c92fea8162ba92611d9f7026c1fa6a7304f1aeea", kill_on_drop: false }`
[INFO] [stdout] 067deca687e40bc05b61d700c92fea8162ba92611d9f7026c1fa6a7304f1aeea
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+dec9417b8611e34e787a3e4c37686b5131f9e5c5" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4c7d8a6ecc57b9023c296a87c33db91555b9b87d0551ad5186d86e8ed3111814
[INFO] running `Command { std: "docker" "start" "-a" "4c7d8a6ecc57b9023c296a87c33db91555b9b87d0551ad5186d86e8ed3111814", kill_on_drop: false }`
[INFO] [stderr]    Compiling head_tail v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/head_tail.rs:18:10
[INFO] [stdout]    |
[INFO] [stdout] 18 |     for (i, line) in reader.lines().enumerate().take(n) {
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.61s
[INFO] running `Command { std: "docker" "inspect" "4c7d8a6ecc57b9023c296a87c33db91555b9b87d0551ad5186d86e8ed3111814", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4c7d8a6ecc57b9023c296a87c33db91555b9b87d0551ad5186d86e8ed3111814", kill_on_drop: false }`
[INFO] [stdout] 4c7d8a6ecc57b9023c296a87c33db91555b9b87d0551ad5186d86e8ed3111814
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+dec9417b8611e34e787a3e4c37686b5131f9e5c5" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 39c0705411550e4d4a07077d9dbd965951fadbcb98f46d2bcc58ab7e5f5e8cf4
[INFO] running `Command { std: "docker" "start" "-a" "39c0705411550e4d4a07077d9dbd965951fadbcb98f46d2bcc58ab7e5f5e8cf4", kill_on_drop: false }`
[INFO] [stderr]    Compiling head_tail v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/head_tail.rs:18:10
[INFO] [stdout]    |
[INFO] [stdout] 18 |     for (i, line) in reader.lines().enumerate().take(n) {
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/head_tail.rs:18:10
[INFO] [stdout]    |
[INFO] [stdout] 18 |     for (i, line) in reader.lines().enumerate().take(n) {
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.56s
[INFO] running `Command { std: "docker" "inspect" "39c0705411550e4d4a07077d9dbd965951fadbcb98f46d2bcc58ab7e5f5e8cf4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "39c0705411550e4d4a07077d9dbd965951fadbcb98f46d2bcc58ab7e5f5e8cf4", kill_on_drop: false }`
[INFO] [stdout] 39c0705411550e4d4a07077d9dbd965951fadbcb98f46d2bcc58ab7e5f5e8cf4
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+dec9417b8611e34e787a3e4c37686b5131f9e5c5" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 0161d6190a4d67d7eb089ddae47d6ce2fc533c638b97993d7b63cea1354dfc00
[INFO] running `Command { std: "docker" "start" "-a" "0161d6190a4d67d7eb089ddae47d6ce2fc533c638b97993d7b63cea1354dfc00", kill_on_drop: false }`
[INFO] [stderr] warning: unused variable: `i`
[INFO] [stderr]   --> src/head_tail.rs:18:10
[INFO] [stderr]    |
[INFO] [stderr] 18 |     for (i, line) in reader.lines().enumerate().take(n) {
[INFO] [stderr]    |          ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stderr] 
[INFO] [stderr] warning: `head_tail` (lib) generated 1 warning (run `cargo fix --lib -p head_tail` to apply 1 suggestion)
[INFO] [stderr] warning: `head_tail` (lib test) generated 1 warning (1 duplicate)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running unittests src/head_tail.rs (/opt/rustwide/target/debug/deps/head_tail-98d9014d3dd2852f)
[INFO] [stderr]      Running unittests src/main.rs (/opt/rustwide/target/debug/deps/head_tail-a01240deec439cdd)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test tests::test_math ... ok
[INFO] [stderr]    Doc-tests head_tail
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.01s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "0161d6190a4d67d7eb089ddae47d6ce2fc533c638b97993d7b63cea1354dfc00", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0161d6190a4d67d7eb089ddae47d6ce2fc533c638b97993d7b63cea1354dfc00", kill_on_drop: false }`
[INFO] [stdout] 0161d6190a4d67d7eb089ddae47d6ce2fc533c638b97993d7b63cea1354dfc00