[INFO] cloning repository https://github.com/abuit/rust-markov
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/abuit/rust-markov" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fabuit%2Frust-markov", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fabuit%2Frust-markov'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 95ec4e97ce1f93dc5a402b4659a30b83966e182f
[INFO] checking abuit/rust-markov against master#936f2600b6c903b04387f74ed5cbce88bb06d243 for pr-91141
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fabuit%2Frust-markov" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/abuit/rust-markov on toolchain 936f2600b6c903b04387f74ed5cbce88bb06d243
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/abuit/rust-markov
[INFO] finished tweaking git repo https://github.com/abuit/rust-markov
[INFO] tweaked toml for git repo https://github.com/abuit/rust-markov written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/abuit/rust-markov already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3ee8198cb2c0b8238dcf7901795b6e91641fc7e288331a1d7e0ef6b5b017d44d
[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" "3ee8198cb2c0b8238dcf7901795b6e91641fc7e288331a1d7e0ef6b5b017d44d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3ee8198cb2c0b8238dcf7901795b6e91641fc7e288331a1d7e0ef6b5b017d44d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3ee8198cb2c0b8238dcf7901795b6e91641fc7e288331a1d7e0ef6b5b017d44d", kill_on_drop: false }`
[INFO] [stdout] 3ee8198cb2c0b8238dcf7901795b6e91641fc7e288331a1d7e0ef6b5b017d44d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6db1914be5de41d12517357314c93fba5a34939535f2f7fdea3f9bebe43acfa8
[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" "6db1914be5de41d12517357314c93fba5a34939535f2f7fdea3f9bebe43acfa8", kill_on_drop: false }`
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking rand v0.6.5
[INFO] [stderr]     Checking rust-markov v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]   --> src/main.rs:62:21
[INFO] [stdout]    |
[INFO] [stdout] 62 |                     &preceding_word_vec.1.push((&text[word_start..counter], 1));
[INFO] [stdout]    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 62 |                     let _ = &preceding_word_vec.1.push((&text[word_start..counter], 1));
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]   --> src/main.rs:62:21
[INFO] [stdout]    |
[INFO] [stdout] 62 |                     &preceding_word_vec.1.push((&text[word_start..counter], 1));
[INFO] [stdout]    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 62 |                     let _ = &preceding_word_vec.1.push((&text[word_start..counter], 1));
[INFO] [stdout]    |                     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.52s
[INFO] running `Command { std: "docker" "inspect" "6db1914be5de41d12517357314c93fba5a34939535f2f7fdea3f9bebe43acfa8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6db1914be5de41d12517357314c93fba5a34939535f2f7fdea3f9bebe43acfa8", kill_on_drop: false }`
[INFO] [stdout] 6db1914be5de41d12517357314c93fba5a34939535f2f7fdea3f9bebe43acfa8