[INFO] cloning repository https://github.com/LearningOS/learn_rust_rustlings-mekyang
[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-mekyang" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-mekyang", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-mekyang'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 13096fe4dce70d43c35b1d226dd1cfbf67932dcd
[INFO] checking LearningOS/learn_rust_rustlings-mekyang 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-mekyang" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang 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-mekyang
[INFO] finished tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang
[INFO] tweaked toml for git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang 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]     Blocking waiting for file lock on package cache
[INFO] [stderr]      Locking 1 package
[INFO] [stderr]     Updating rustlings v4.7.1 (/workspace/builds/worker-1-tc1/source) -> v4.8.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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] 4a703921d0be9dc8ac62d301319b3f31549f31a2bf0fa7734b200ee252938efd
[INFO] running `Command { std: "docker" "start" "-a" "4a703921d0be9dc8ac62d301319b3f31549f31a2bf0fa7734b200ee252938efd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4a703921d0be9dc8ac62d301319b3f31549f31a2bf0fa7734b200ee252938efd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4a703921d0be9dc8ac62d301319b3f31549f31a2bf0fa7734b200ee252938efd", kill_on_drop: false }`
[INFO] [stdout] 4a703921d0be9dc8ac62d301319b3f31549f31a2bf0fa7734b200ee252938efd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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] 41278a734da2ccbe1fbc7ea1e83ebe79f820a4f303e11337f4bbfe94fc848171
[INFO] running `Command { std: "docker" "start" "-a" "41278a734da2ccbe1fbc7ea1e83ebe79f820a4f303e11337f4bbfe94fc848171", kill_on_drop: false }`
[INFO] [stderr]     Checking rustlings v4.8.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.67s
[INFO] running `Command { std: "docker" "inspect" "41278a734da2ccbe1fbc7ea1e83ebe79f820a4f303e11337f4bbfe94fc848171", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "41278a734da2ccbe1fbc7ea1e83ebe79f820a4f303e11337f4bbfe94fc848171", kill_on_drop: false }`
[INFO] [stdout] 41278a734da2ccbe1fbc7ea1e83ebe79f820a4f303e11337f4bbfe94fc848171
[INFO] checking LearningOS/learn_rust_rustlings-mekyang against try#2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2 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-mekyang" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang on toolchain 2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang
[INFO] finished tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang
[INFO] tweaked toml for git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/LearningOS/learn_rust_rustlings-mekyang 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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]      Locking 1 package
[INFO] [stderr]     Updating rustlings v4.7.1 (/workspace/builds/worker-1-tc2/source) -> v4.8.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 179ac50751887951c4573c885c1aa458c83f7148bfc867f25deddfdb48fa85cd
[INFO] running `Command { std: "docker" "start" "-a" "179ac50751887951c4573c885c1aa458c83f7148bfc867f25deddfdb48fa85cd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "179ac50751887951c4573c885c1aa458c83f7148bfc867f25deddfdb48fa85cd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "179ac50751887951c4573c885c1aa458c83f7148bfc867f25deddfdb48fa85cd", kill_on_drop: false }`
[INFO] [stdout] 179ac50751887951c4573c885c1aa458c83f7148bfc867f25deddfdb48fa85cd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 92f38902259d49817548d08c18557ab45fcf65f5e0900e0f0088b63ff4d13d7d
[INFO] running `Command { std: "docker" "start" "-a" "92f38902259d49817548d08c18557ab45fcf65f5e0900e0f0088b63ff4d13d7d", 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" "92f38902259d49817548d08c18557ab45fcf65f5e0900e0f0088b63ff4d13d7d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "92f38902259d49817548d08c18557ab45fcf65f5e0900e0f0088b63ff4d13d7d", kill_on_drop: false }`
[INFO] [stdout] 92f38902259d49817548d08c18557ab45fcf65f5e0900e0f0088b63ff4d13d7d