[INFO] cloning repository https://github.com/a7p/learn-rust-stringmixer
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/a7p/learn-rust-stringmixer" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa7p%2Flearn-rust-stringmixer", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa7p%2Flearn-rust-stringmixer'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] fcb40481b878e6596a5284902fa4cf1a2a04252e
[INFO] checking a7p/learn-rust-stringmixer against master#0599f3403366d9c57f0625e6de3af214b5042a90 for pr-87710
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa7p%2Flearn-rust-stringmixer" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/a7p/learn-rust-stringmixer on toolchain 0599f3403366d9c57f0625e6de3af214b5042a90
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0599f3403366d9c57f0625e6de3af214b5042a90" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/a7p/learn-rust-stringmixer
[INFO] finished tweaking git repo https://github.com/a7p/learn-rust-stringmixer
[INFO] tweaked toml for git repo https://github.com/a7p/learn-rust-stringmixer written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/a7p/learn-rust-stringmixer already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0599f3403366d9c57f0625e6de3af214b5042a90" "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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+0599f3403366d9c57f0625e6de3af214b5042a90" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f5edbf91d6846acd51187929791110e6ad1aa306cb3668afe3084615a0b55af4
[INFO] running `Command { std: "docker" "start" "-a" "f5edbf91d6846acd51187929791110e6ad1aa306cb3668afe3084615a0b55af4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f5edbf91d6846acd51187929791110e6ad1aa306cb3668afe3084615a0b55af4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f5edbf91d6846acd51187929791110e6ad1aa306cb3668afe3084615a0b55af4", kill_on_drop: false }`
[INFO] [stdout] f5edbf91d6846acd51187929791110e6ad1aa306cb3668afe3084615a0b55af4
[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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+0599f3403366d9c57f0625e6de3af214b5042a90" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] cea58e16fcee2c7c649cf9eddfa37f40458d2ca1f0fb0c5f6dc39464e459698f
[INFO] running `Command { std: "docker" "start" "-a" "cea58e16fcee2c7c649cf9eddfa37f40458d2ca1f0fb0c5f6dc39464e459698f", kill_on_drop: false }`
[INFO] [stderr]    Compiling winapi-build v0.1.1
[INFO] [stderr]     Checking winapi v0.2.5
[INFO] [stderr]     Checking libc v0.2.2
[INFO] [stderr]     Checking unicode-segmentation v0.1.2
[INFO] [stderr]    Compiling advapi32-sys v0.1.2
[INFO] [stderr]     Checking rand v0.3.12
[INFO] [stderr]     Checking stringmixer v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let mut v = &mut g[1..l];
[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] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let mut v = &mut g[1..l];
[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] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.99s
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "cea58e16fcee2c7c649cf9eddfa37f40458d2ca1f0fb0c5f6dc39464e459698f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cea58e16fcee2c7c649cf9eddfa37f40458d2ca1f0fb0c5f6dc39464e459698f", kill_on_drop: false }`
[INFO] [stdout] cea58e16fcee2c7c649cf9eddfa37f40458d2ca1f0fb0c5f6dc39464e459698f