[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#5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftynr426%2Fregex_learn" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/tynr426/regex_learn on toolchain 5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "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-6/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" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "metadata" "--no-deps" "--format-version=1", 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] 25013a998afc88138817d5e369d9ad260ac26c014e4a7cfac59b5503d0e0c55b
[INFO] running `Command { std: "docker" "start" "-a" "25013a998afc88138817d5e369d9ad260ac26c014e4a7cfac59b5503d0e0c55b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "25013a998afc88138817d5e369d9ad260ac26c014e4a7cfac59b5503d0e0c55b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "25013a998afc88138817d5e369d9ad260ac26c014e4a7cfac59b5503d0e0c55b", kill_on_drop: false }`
[INFO] [stdout] 25013a998afc88138817d5e369d9ad260ac26c014e4a7cfac59b5503d0e0c55b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "+5a8a44196b3cf099f8c9b0156bd902eaec0b4e5f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8c82716c40bfaf6c99dd00da0ca4382e81e51e797a3c541c664bcd7933960d9f
[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" "8c82716c40bfaf6c99dd00da0ca4382e81e51e797a3c541c664bcd7933960d9f", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.2.1
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]     Checking aho-corasick v0.7.6
[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 4.13s
[INFO] running `Command { std: "docker" "inspect" "8c82716c40bfaf6c99dd00da0ca4382e81e51e797a3c541c664bcd7933960d9f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8c82716c40bfaf6c99dd00da0ca4382e81e51e797a3c541c664bcd7933960d9f", kill_on_drop: false }`
[INFO] [stdout] 8c82716c40bfaf6c99dd00da0ca4382e81e51e797a3c541c664bcd7933960d9f