[INFO] cloning repository https://github.com/house-of-vanity/bulls_and_cows
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/house-of-vanity/bulls_and_cows" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhouse-of-vanity%2Fbulls_and_cows", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhouse-of-vanity%2Fbulls_and_cows'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b249589bbd57575c18c7209e5d73f108d78e524c
[INFO] checking house-of-vanity/bulls_and_cows against try#07fecb9cf34c4979a772ba38c99d6d9144768413 for pr-87710
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhouse-of-vanity%2Fbulls_and_cows" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/house-of-vanity/bulls_and_cows on toolchain 07fecb9cf34c4979a772ba38c99d6d9144768413
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+07fecb9cf34c4979a772ba38c99d6d9144768413" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/house-of-vanity/bulls_and_cows
[INFO] finished tweaking git repo https://github.com/house-of-vanity/bulls_and_cows
[INFO] tweaked toml for git repo https://github.com/house-of-vanity/bulls_and_cows written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/house-of-vanity/bulls_and_cows already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+07fecb9cf34c4979a772ba38c99d6d9144768413" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "+07fecb9cf34c4979a772ba38c99d6d9144768413" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 41f42672eb008f78e815f84dca962e109a504d569b631e8a8b102e62e615b596
[INFO] running `Command { std: "docker" "start" "-a" "41f42672eb008f78e815f84dca962e109a504d569b631e8a8b102e62e615b596", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "41f42672eb008f78e815f84dca962e109a504d569b631e8a8b102e62e615b596", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "41f42672eb008f78e815f84dca962e109a504d569b631e8a8b102e62e615b596", kill_on_drop: false }`
[INFO] [stdout] 41f42672eb008f78e815f84dca962e109a504d569b631e8a8b102e62e615b596
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "+07fecb9cf34c4979a772ba38c99d6d9144768413" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 845372e945fdf7a798752a8a47faa6b05c92ee4f6719512bc769c667f14f0569
[INFO] running `Command { std: "docker" "start" "-a" "845372e945fdf7a798752a8a47faa6b05c92ee4f6719512bc769c667f14f0569", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.66
[INFO] [stderr]    Compiling getrandom v0.1.13
[INFO] [stderr]     Checking ppv-lite86 v0.2.6
[INFO] [stderr]     Checking c2-chacha v0.2.3
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.2
[INFO] [stderr]     Checking bulls_and_cows v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/main.rs:142:17
[INFO] [stdout]     |
[INFO] [stdout] 142 |                 &game.start();
[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] 142 |                 let _ = &game.start();
[INFO] [stdout]     |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/main.rs:142:17
[INFO] [stdout]     |
[INFO] [stdout] 142 |                 &game.start();
[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] 142 |                 let _ = &game.start();
[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 3.97s
[INFO] running `Command { std: "docker" "inspect" "845372e945fdf7a798752a8a47faa6b05c92ee4f6719512bc769c667f14f0569", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "845372e945fdf7a798752a8a47faa6b05c92ee4f6719512bc769c667f14f0569", kill_on_drop: false }`
[INFO] [stdout] 845372e945fdf7a798752a8a47faa6b05c92ee4f6719512bc769c667f14f0569