[INFO] cloning repository https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927
[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-ZHOUAXING927" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-ZHOUAXING927", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-ZHOUAXING927'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7171f260762ea6bf8efeecbecff1e2503ccf8bae
[INFO] checking LearningOS/learn_rust_rustlings-ZHOUAXING927 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-ZHOUAXING927" "/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-ZHOUAXING927 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-ZHOUAXING927
[INFO] finished tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927
[INFO] tweaked toml for git repo https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927 written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927 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] 487fb2ef268c7ccea9ef00088d7ff50a8fcddde71ed5d02cc1a8f31e0d661314
[INFO] running `Command { std: "docker" "start" "-a" "487fb2ef268c7ccea9ef00088d7ff50a8fcddde71ed5d02cc1a8f31e0d661314", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "487fb2ef268c7ccea9ef00088d7ff50a8fcddde71ed5d02cc1a8f31e0d661314", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "487fb2ef268c7ccea9ef00088d7ff50a8fcddde71ed5d02cc1a8f31e0d661314", kill_on_drop: false }`
[INFO] [stdout] 487fb2ef268c7ccea9ef00088d7ff50a8fcddde71ed5d02cc1a8f31e0d661314
[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] db7e9a591c65f53d80b69e884d7113c09a62e4f5d0f1d60014b639f636ad056b
[INFO] running `Command { std: "docker" "start" "-a" "db7e9a591c65f53d80b69e884d7113c09a62e4f5d0f1d60014b639f636ad056b", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.100
[INFO] [stderr]    Compiling syn v1.0.75
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling serde_derive v1.0.129
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]    Compiling serde v1.0.129
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling serde_json v1.0.81
[INFO] [stderr]     Checking itoa v1.0.2
[INFO] [stderr]    Compiling unicode-segmentation v1.8.0
[INFO] [stderr]     Checking slab v0.4.4
[INFO] [stderr]     Checking once_cell v1.10.0
[INFO] [stderr]     Checking same-file v1.0.6
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]     Checking lazycell v1.3.0
[INFO] [stderr]    Compiling argh_shared v0.1.5
[INFO] [stderr]     Checking walkdir v2.3.2
[INFO] [stderr]     Checking predicates-core v1.0.2
[INFO] [stderr]    Compiling escargot v0.4.0
[INFO] [stderr]     Checking number_prefix v0.4.0
[INFO] [stderr]     Checking home v0.5.3
[INFO] [stderr]     Checking aho-corasick v0.7.18
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]     Checking normalize-line-endings v0.3.0
[INFO] [stderr]     Checking treeline v0.1.0
[INFO] [stderr]     Checking difference v2.0.0
[INFO] [stderr]     Checking glob v0.3.0
[INFO] [stderr]     Checking predicates-tree v1.0.3
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking net2 v0.2.37
[INFO] [stderr]     Checking terminal_size v0.1.17
[INFO] [stderr]     Checking inotify-sys v0.1.5
[INFO] [stderr]     Checking filetime v0.2.15
[INFO] [stderr]     Checking inotify v0.7.1
[INFO] [stderr]     Checking mio v0.6.23
[INFO] [stderr]     Checking regex v1.5.5
[INFO] [stderr]     Checking float-cmp v0.8.0
[INFO] [stderr]     Checking mio-extras v2.0.6
[INFO] [stderr]     Checking notify v4.0.17
[INFO] [stderr]     Checking console v0.15.0
[INFO] [stderr]     Checking predicates v1.0.8
[INFO] [stderr]     Checking indicatif v0.16.2
[INFO] [stderr]    Compiling argh_derive v0.1.5
[INFO] [stderr]     Checking argh v0.1.5
[INFO] [stderr]     Checking toml v0.5.9
[INFO] [stderr]     Checking rustlings v4.8.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking assert_cmd v0.11.1
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 25.64s
[INFO] running `Command { std: "docker" "inspect" "db7e9a591c65f53d80b69e884d7113c09a62e4f5d0f1d60014b639f636ad056b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "db7e9a591c65f53d80b69e884d7113c09a62e4f5d0f1d60014b639f636ad056b", kill_on_drop: false }`
[INFO] [stdout] db7e9a591c65f53d80b69e884d7113c09a62e4f5d0f1d60014b639f636ad056b
[INFO] checking LearningOS/learn_rust_rustlings-ZHOUAXING927 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-ZHOUAXING927" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927 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-ZHOUAXING927
[INFO] finished tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927
[INFO] tweaked toml for git repo https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927 written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/LearningOS/learn_rust_rustlings-ZHOUAXING927 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-7-tc2/source) -> v4.8.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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] 107bc568eaf76bed7e9cb59d2b68e565d8c7fb4a9fe21c60d42f1f5baf488af1
[INFO] running `Command { std: "docker" "start" "-a" "107bc568eaf76bed7e9cb59d2b68e565d8c7fb4a9fe21c60d42f1f5baf488af1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "107bc568eaf76bed7e9cb59d2b68e565d8c7fb4a9fe21c60d42f1f5baf488af1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "107bc568eaf76bed7e9cb59d2b68e565d8c7fb4a9fe21c60d42f1f5baf488af1", kill_on_drop: false }`
[INFO] [stdout] 107bc568eaf76bed7e9cb59d2b68e565d8c7fb4a9fe21c60d42f1f5baf488af1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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] a27f67a308e5cd53f3cecc6cb6381048f03dba16d69b018eaf40173abfeb636f
[INFO] running `Command { std: "docker" "start" "-a" "a27f67a308e5cd53f3cecc6cb6381048f03dba16d69b018eaf40173abfeb636f", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.100
[INFO] [stderr]    Compiling syn v1.0.75
[INFO] [stderr]    Compiling memchr v2.4.1
[INFO] [stderr]    Compiling serde_derive v1.0.129
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]    Compiling serde v1.0.129
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling serde_json v1.0.81
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling unicode-segmentation v1.8.0
[INFO] [stderr]     Checking itoa v1.0.2
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]     Checking slab v0.4.4
[INFO] [stderr]    Compiling argh_shared v0.1.5
[INFO] [stderr]     Checking once_cell v1.10.0
[INFO] [stderr]     Checking lazycell v1.3.0
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]     Checking same-file v1.0.6
[INFO] [stderr]     Checking number_prefix v0.4.0
[INFO] [stderr]    Compiling escargot v0.4.0
[INFO] [stderr]     Checking walkdir v2.3.2
[INFO] [stderr]     Checking predicates-core v1.0.2
[INFO] [stderr]     Checking aho-corasick v0.7.18
[INFO] [stderr]     Checking difference v2.0.0
[INFO] [stderr]     Checking normalize-line-endings v0.3.0
[INFO] [stderr]     Checking treeline v0.1.0
[INFO] [stderr]     Checking home v0.5.3
[INFO] [stderr]     Checking glob v0.3.0
[INFO] [stderr]     Checking predicates-tree v1.0.3
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking net2 v0.2.37
[INFO] [stderr]     Checking terminal_size v0.1.17
[INFO] [stderr]     Checking inotify-sys v0.1.5
[INFO] [stderr]     Checking filetime v0.2.15
[INFO] [stderr]     Checking inotify v0.7.1
[INFO] [stderr]     Checking mio v0.6.23
[INFO] [stderr]     Checking float-cmp v0.8.0
[INFO] [stderr]     Checking regex v1.5.5
[INFO] [stderr]     Checking mio-extras v2.0.6
[INFO] [stderr]     Checking notify v4.0.17
[INFO] [stderr]     Checking console v0.15.0
[INFO] [stderr]     Checking predicates v1.0.8
[INFO] [stderr]    Compiling argh_derive v0.1.5
[INFO] [stderr]     Checking indicatif v0.16.2
[INFO] [stderr]     Checking argh v0.1.5
[INFO] [stderr]     Checking toml v0.5.9
[INFO] [stderr]     Checking rustlings v4.8.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking assert_cmd v0.11.1
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 16.99s
[INFO] running `Command { std: "docker" "inspect" "a27f67a308e5cd53f3cecc6cb6381048f03dba16d69b018eaf40173abfeb636f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a27f67a308e5cd53f3cecc6cb6381048f03dba16d69b018eaf40173abfeb636f", kill_on_drop: false }`
[INFO] [stdout] a27f67a308e5cd53f3cecc6cb6381048f03dba16d69b018eaf40173abfeb636f