[INFO] updating cached repository https://github.com/lperson/which_rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 06d6c0d4d053c898719e9c3f088a18fef288e498
[INFO] checking lperson/which_rust against try#22dd2dd1dc07f63ae9394352d412f020d2985684 for pr-74627
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flperson%2Fwhich_rust" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/lperson/which_rust on toolchain 22dd2dd1dc07f63ae9394352d412f020d2985684
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+22dd2dd1dc07f63ae9394352d412f020d2985684" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/lperson/which_rust
[INFO] finished tweaking git repo https://github.com/lperson/which_rust
[INFO] tweaked toml for git repo https://github.com/lperson/which_rust written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/lperson/which_rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+22dd2dd1dc07f63ae9394352d412f020d2985684" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+22dd2dd1dc07f63ae9394352d412f020d2985684" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f12750569674857591f24caeaac4d2a758fe1c502163a53f10a19b3f722f6b99
[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" "f12750569674857591f24caeaac4d2a758fe1c502163a53f10a19b3f722f6b99", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f12750569674857591f24caeaac4d2a758fe1c502163a53f10a19b3f722f6b99", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f12750569674857591f24caeaac4d2a758fe1c502163a53f10a19b3f722f6b99", kill_on_drop: false }`
[INFO] [stdout] f12750569674857591f24caeaac4d2a758fe1c502163a53f10a19b3f722f6b99
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+22dd2dd1dc07f63ae9394352d412f020d2985684" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 31be5a1a33e92bfd62474029b8fd25fce2aaa645ee9eaca6cf5b528d39c96112
[INFO] running `Command { std: "docker" "start" "-a" "31be5a1a33e92bfd62474029b8fd25fce2aaa645ee9eaca6cf5b528d39c96112", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.62
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]     Checking unicode-width v0.1.6
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking atty v0.2.13
[INFO] [stderr]     Checking dirs-sys v0.3.4
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking dirs v2.0.2
[INFO] [stderr]     Checking which_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 8.84s
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let mut output: process::Output;
[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:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let mut output: process::Output;
[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] running `Command { std: "docker" "inspect" "31be5a1a33e92bfd62474029b8fd25fce2aaa645ee9eaca6cf5b528d39c96112", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "31be5a1a33e92bfd62474029b8fd25fce2aaa645ee9eaca6cf5b528d39c96112", kill_on_drop: false }`
[INFO] [stdout] 31be5a1a33e92bfd62474029b8fd25fce2aaa645ee9eaca6cf5b528d39c96112