[INFO] cloning repository https://github.com/nam2ee/rust_race
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/nam2ee/rust_race" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnam2ee%2Frust_race", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnam2ee%2Frust_race'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3bd7c9626a3639be6cb9f096c39423c928f73534
[INFO] checking nam2ee/rust_race against master#4b596bbd847672da87763b76171687d3544863c2 for pr-144544
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnam2ee%2Frust_race" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/nam2ee/rust_race
[INFO] finished tweaking git repo https://github.com/nam2ee/rust_race
[INFO] tweaked toml for git repo https://github.com/nam2ee/rust_race written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/nam2ee/rust_race on toolchain 4b596bbd847672da87763b76171687d3544863c2
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4b596bbd847672da87763b76171687d3544863c2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/nam2ee/rust_race 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" "+4b596bbd847672da87763b76171687d3544863c2" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+4b596bbd847672da87763b76171687d3544863c2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3ce7d386f2ab86ad01478c2b974542dd57d094595bd517afbc1fcb3499adc1e2
[INFO] running `Command { std: "docker" "start" "-a" "3ce7d386f2ab86ad01478c2b974542dd57d094595bd517afbc1fcb3499adc1e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3ce7d386f2ab86ad01478c2b974542dd57d094595bd517afbc1fcb3499adc1e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3ce7d386f2ab86ad01478c2b974542dd57d094595bd517afbc1fcb3499adc1e2", kill_on_drop: false }`
[INFO] [stdout] 3ce7d386f2ab86ad01478c2b974542dd57d094595bd517afbc1fcb3499adc1e2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+4b596bbd847672da87763b76171687d3544863c2" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c400f2e75877b512f10b529c71c37d93cb747fabb242cf7e7f32ac4463bc2e03
[INFO] running `Command { std: "docker" "start" "-a" "c400f2e75877b512f10b529c71c37d93cb747fabb242cf7e7f32ac4463bc2e03", kill_on_drop: false }`
[INFO] [stderr]     Checking preference v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let r1 = &s;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `r1`
[INFO] [stdout]   --> src/main.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let r1 = &s;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_r1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/main.rs:31:9
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let s: String = no_dangle();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/main.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let s: &String = &no_dangle();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/main.rs:31:9
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let s: String = no_dangle();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/main.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let s: &String = &no_dangle();
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let mut s = String::from("hello");
[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: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:23:9
[INFO] [stdout]    |
[INFO] [stdout] 23 |     let mut s = String::from("hello");
[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` profile [unoptimized + debuginfo] target(s) in 0.08s
[INFO] running `Command { std: "docker" "inspect" "c400f2e75877b512f10b529c71c37d93cb747fabb242cf7e7f32ac4463bc2e03", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c400f2e75877b512f10b529c71c37d93cb747fabb242cf7e7f32ac4463bc2e03", kill_on_drop: false }`
[INFO] [stdout] c400f2e75877b512f10b529c71c37d93cb747fabb242cf7e7f32ac4463bc2e03