[INFO] cloning repository https://github.com/tynr426/regex_learn
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tynr426/regex_learn" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftynr426%2Fregex_learn", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftynr426%2Fregex_learn'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f59ec04f199a67c8bdaebe162b45a52c8b8e4cb5
[INFO] checking tynr426/regex_learn against master#f82664191d0e8764b7435b9d72eb0e366b8b1464 for pr-83354
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftynr426%2Fregex_learn" "/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/tynr426/regex_learn on toolchain f82664191d0e8764b7435b9d72eb0e366b8b1464
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/tynr426/regex_learn
[INFO] finished tweaking git repo https://github.com/tynr426/regex_learn
[INFO] tweaked toml for git repo https://github.com/tynr426/regex_learn written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/tynr426/regex_learn already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "fetch" "--locked" "--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" "rustops/crates-build-env@sha256:4f92631de1aa59f8320307485d3b3c869a5c90ab1d76ce2cffab9807b8c9a1fb" "/opt/rustwide/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 2ca181cb798b42cb7ae173a045bd92c2d0cb84582856b08b044a113358e478e5
[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" "2ca181cb798b42cb7ae173a045bd92c2d0cb84582856b08b044a113358e478e5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2ca181cb798b42cb7ae173a045bd92c2d0cb84582856b08b044a113358e478e5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2ca181cb798b42cb7ae173a045bd92c2d0cb84582856b08b044a113358e478e5", kill_on_drop: false }`
[INFO] [stdout] 2ca181cb798b42cb7ae173a045bd92c2d0cb84582856b08b044a113358e478e5
[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" "rustops/crates-build-env@sha256:4f92631de1aa59f8320307485d3b3c869a5c90ab1d76ce2cffab9807b8c9a1fb" "/opt/rustwide/cargo-home/bin/cargo" "+f82664191d0e8764b7435b9d72eb0e366b8b1464" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 2e3cd534402d0f73bde0ed793cd24cac7f5c38550efd38665c3e6b07f9ae920b
[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" "2e3cd534402d0f73bde0ed793cd24cac7f5c38550efd38665c3e6b07f9ae920b", kill_on_drop: false }`
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]     Checking regex v1.3.1
[INFO] [stderr]     Checking regex_learn v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:55:9
[INFO] [stdout]    |
[INFO] [stdout] 55 |     let mut str2 = "{xy:7,xx:\"kk\",\"key\":\"bbb\"}";
[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:55:9
[INFO] [stdout]    |
[INFO] [stdout] 55 |     let mut str2 = "{xy:7,xx:\"kk\",\"key\":\"bbb\"}";
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.28s
[INFO] running `Command { std: "docker" "inspect" "2e3cd534402d0f73bde0ed793cd24cac7f5c38550efd38665c3e6b07f9ae920b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2e3cd534402d0f73bde0ed793cd24cac7f5c38550efd38665c3e6b07f9ae920b", kill_on_drop: false }`
[INFO] [stdout] 2e3cd534402d0f73bde0ed793cd24cac7f5c38550efd38665c3e6b07f9ae920b