[INFO] cloning repository https://github.com/fteychene/rust-error-playground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/fteychene/rust-error-playground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffteychene%2Frust-error-playground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffteychene%2Frust-error-playground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] fa8ce5306515ca1d2c77d022d760ab7c00360f86
[INFO] checking fteychene/rust-error-playground against master#3aedcf06b73fc36feeebca3d579e1d2a6c40acc5 for pr-65819
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffteychene%2Frust-error-playground" "/workspace/builds/worker-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fteychene/rust-error-playground on toolchain 3aedcf06b73fc36feeebca3d579e1d2a6c40acc5
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/fteychene/rust-error-playground
[INFO] finished tweaking git repo https://github.com/fteychene/rust-error-playground
[INFO] tweaked toml for git repo https://github.com/fteychene/rust-error-playground written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/fteychene/rust-error-playground already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 217aed787bdf331928f48156c7c991b762e6fb70c068009c2fbab8845d1cab10
[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" "217aed787bdf331928f48156c7c991b762e6fb70c068009c2fbab8845d1cab10", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "217aed787bdf331928f48156c7c991b762e6fb70c068009c2fbab8845d1cab10", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "217aed787bdf331928f48156c7c991b762e6fb70c068009c2fbab8845d1cab10", kill_on_drop: false }`
[INFO] [stdout] 217aed787bdf331928f48156c7c991b762e6fb70c068009c2fbab8845d1cab10
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+3aedcf06b73fc36feeebca3d579e1d2a6c40acc5" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] df3e0da1281e739b331f3a55e122d8aa3f93684a133b03adf86afc71de32735b
[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" "df3e0da1281e739b331f3a55e122d8aa3f93684a133b03adf86afc71de32735b", 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 vanilla v0.1.0 (/opt/rustwide/workdir/vanilla)
[INFO] [stderr]     Checking vanillacustom v0.1.0 (/opt/rustwide/workdir/vanillacustom)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> vanilla/src/main.rs:34:18
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn remove_header(mut chapters: Vec<String>) -> Result<Vec<String>, Box<dyn Error>> {
[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]   --> vanilla/src/main.rs:34:18
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn remove_header(mut chapters: Vec<String>) -> Result<Vec<String>, Box<dyn Error>> {
[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 6.11s
[INFO] running `Command { std: "docker" "inspect" "df3e0da1281e739b331f3a55e122d8aa3f93684a133b03adf86afc71de32735b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "df3e0da1281e739b331f3a55e122d8aa3f93684a133b03adf86afc71de32735b", kill_on_drop: false }`
[INFO] [stdout] df3e0da1281e739b331f3a55e122d8aa3f93684a133b03adf86afc71de32735b