[INFO] cloning repository https://github.com/LearningOS/learn_rust_rustlings-kgdpewfn520
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/LearningOS/learn_rust_rustlings-kgdpewfn520" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-kgdpewfn520", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-kgdpewfn520'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] cc954a61e7c016c0aadcb0e79521c07f4ed7dea6
[INFO] checking LearningOS/learn_rust_rustlings-kgdpewfn520 against master#385fa9d845dd326c6bbfd58c22244215e431948a for never-type-fallback-to-never
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-kgdpewfn520" "/workspace/builds/worker-7-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/LearningOS/learn_rust_rustlings-kgdpewfn520 on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-kgdpewfn520
[INFO] finished tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-kgdpewfn520
[INFO] tweaked toml for git repo https://github.com/LearningOS/learn_rust_rustlings-kgdpewfn520 written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/LearningOS/learn_rust_rustlings-kgdpewfn520 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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]      Locking 1 package
[INFO] [stderr]     Updating rustlings v4.7.1 (/workspace/builds/worker-7-tc1/source) -> v4.8.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8c7773b1b9e0ceee0885b94928a3b0f4a2f1b57dcc748d508811a22b661810af
[INFO] running `Command { std: "docker" "start" "-a" "8c7773b1b9e0ceee0885b94928a3b0f4a2f1b57dcc748d508811a22b661810af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8c7773b1b9e0ceee0885b94928a3b0f4a2f1b57dcc748d508811a22b661810af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8c7773b1b9e0ceee0885b94928a3b0f4a2f1b57dcc748d508811a22b661810af", kill_on_drop: false }`
[INFO] [stdout] 8c7773b1b9e0ceee0885b94928a3b0f4a2f1b57dcc748d508811a22b661810af
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c333e2c9dc47bceb5d8b8a596f95ea9e8a57edea6329ca9488ca4e84df7e67b7
[INFO] running `Command { std: "docker" "start" "-a" "c333e2c9dc47bceb5d8b8a596f95ea9e8a57edea6329ca9488ca4e84df7e67b7", kill_on_drop: false }`
[INFO] [stderr]     Checking rustlings v4.8.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.59s
[INFO] running `Command { std: "docker" "inspect" "c333e2c9dc47bceb5d8b8a596f95ea9e8a57edea6329ca9488ca4e84df7e67b7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c333e2c9dc47bceb5d8b8a596f95ea9e8a57edea6329ca9488ca4e84df7e67b7", kill_on_drop: false }`
[INFO] [stdout] c333e2c9dc47bceb5d8b8a596f95ea9e8a57edea6329ca9488ca4e84df7e67b7