[INFO] fetching crate briliang_exercise 0.1.0...
[INFO] checking briliang_exercise-0.1.0 against try#6f12b8fe67b4eed2e838dab803ed9493b9d62c0f for pr-79073
[INFO] extracting crate briliang_exercise 0.1.0 into /workspace/builds/worker-9/source
[INFO] validating manifest of crates.io crate briliang_exercise 0.1.0 on toolchain 6f12b8fe67b4eed2e838dab803ed9493b9d62c0f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6f12b8fe67b4eed2e838dab803ed9493b9d62c0f" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate briliang_exercise 0.1.0
[INFO] finished tweaking crates.io crate briliang_exercise 0.1.0
[INFO] tweaked toml for crates.io crate briliang_exercise 0.1.0 written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6f12b8fe67b4eed2e838dab803ed9493b9d62c0f" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6f12b8fe67b4eed2e838dab803ed9493b9d62c0f" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+6f12b8fe67b4eed2e838dab803ed9493b9d62c0f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c07a9a144297cee2f499d0077fcfb14cdde5ae538ed4a86caaf5d3ed97e2ef2f
[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" "c07a9a144297cee2f499d0077fcfb14cdde5ae538ed4a86caaf5d3ed97e2ef2f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c07a9a144297cee2f499d0077fcfb14cdde5ae538ed4a86caaf5d3ed97e2ef2f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c07a9a144297cee2f499d0077fcfb14cdde5ae538ed4a86caaf5d3ed97e2ef2f", kill_on_drop: false }`
[INFO] [stdout] c07a9a144297cee2f499d0077fcfb14cdde5ae538ed4a86caaf5d3ed97e2ef2f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+6f12b8fe67b4eed2e838dab803ed9493b9d62c0f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7f93c96e0d89039ff6653d4681e7171d157e2c55990850e44fc87bff0d81dbe9
[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" "7f93c96e0d89039ff6653d4681e7171d157e2c55990850e44fc87bff0d81dbe9", kill_on_drop: false }`
[INFO] [stderr]     Checking rand_core v0.4.2
[INFO] [stderr]    Compiling autocfg v0.1.7
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand_jitter v0.1.4
[INFO] [stderr]     Checking rand_hc v0.1.0
[INFO] [stderr]     Checking rand_xorshift v0.1.1
[INFO] [stderr]     Checking rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking briliang_exercise v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/functional_feature/mod.rs:225:13
[INFO] [stdout]     |
[INFO] [stdout] 225 |         let mut counter = Counter::new();
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 7.60s
[INFO] running `Command { std: "docker" "inspect" "7f93c96e0d89039ff6653d4681e7171d157e2c55990850e44fc87bff0d81dbe9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7f93c96e0d89039ff6653d4681e7171d157e2c55990850e44fc87bff0d81dbe9", kill_on_drop: false }`
[INFO] [stdout] 7f93c96e0d89039ff6653d4681e7171d157e2c55990850e44fc87bff0d81dbe9