[INFO] cloning repository https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh
[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-Mayflyyh" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-Mayflyyh", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-Mayflyyh'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] dc70110e4b91d0dd33c267c65b3a2728a1faca73
[INFO] checking LearningOS/learn_rust_rustlings-Mayflyyh against master#ceab6128fa48a616bfd3e3adf4bc80133b8ee223 for no-never-type-fallback
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-Mayflyyh" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh on toolchain ceab6128fa48a616bfd3e3adf4bc80133b8ee223
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh
[INFO] finished tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh
[INFO] tweaked toml for git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh 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" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7f4ecf381b0d0f459bd1f6be8893b3f481d4f1af02777cea54a5288038e1a2b7
[INFO] running `Command { std: "docker" "start" "-a" "7f4ecf381b0d0f459bd1f6be8893b3f481d4f1af02777cea54a5288038e1a2b7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7f4ecf381b0d0f459bd1f6be8893b3f481d4f1af02777cea54a5288038e1a2b7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7f4ecf381b0d0f459bd1f6be8893b3f481d4f1af02777cea54a5288038e1a2b7", kill_on_drop: false }`
[INFO] [stdout] 7f4ecf381b0d0f459bd1f6be8893b3f481d4f1af02777cea54a5288038e1a2b7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 42e36c013b434cd7da853a03912f36107c814af48039b647e504f32f244c8a30
[INFO] running `Command { std: "docker" "start" "-a" "42e36c013b434cd7da853a03912f36107c814af48039b647e504f32f244c8a30", kill_on_drop: false }`
[INFO] [stderr]     Checking rustlings v4.8.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.34s
[INFO] running `Command { std: "docker" "inspect" "42e36c013b434cd7da853a03912f36107c814af48039b647e504f32f244c8a30", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "42e36c013b434cd7da853a03912f36107c814af48039b647e504f32f244c8a30", kill_on_drop: false }`
[INFO] [stdout] 42e36c013b434cd7da853a03912f36107c814af48039b647e504f32f244c8a30
[INFO] checking LearningOS/learn_rust_rustlings-Mayflyyh against try#3a4bc97f6385a3aa300a4fd689b44350e54fd676 for no-never-type-fallback
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLearningOS%2Flearn_rust_rustlings-Mayflyyh" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh on toolchain 3a4bc97f6385a3aa300a4fd689b44350e54fd676
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh
[INFO] finished tweaking git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh
[INFO] tweaked toml for git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/LearningOS/learn_rust_rustlings-Mayflyyh 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" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 50ae66b0bf425ff759c21e5f42e5608cc9dd14d799b78e51df7885abac72cc82
[INFO] running `Command { std: "docker" "start" "-a" "50ae66b0bf425ff759c21e5f42e5608cc9dd14d799b78e51df7885abac72cc82", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "50ae66b0bf425ff759c21e5f42e5608cc9dd14d799b78e51df7885abac72cc82", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "50ae66b0bf425ff759c21e5f42e5608cc9dd14d799b78e51df7885abac72cc82", kill_on_drop: false }`
[INFO] [stdout] 50ae66b0bf425ff759c21e5f42e5608cc9dd14d799b78e51df7885abac72cc82
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a4aa3e13dcc95b32d41292b897b31bf73b802a8052380c48ef81174119fb2be9
[INFO] running `Command { std: "docker" "start" "-a" "a4aa3e13dcc95b32d41292b897b31bf73b802a8052380c48ef81174119fb2be9", kill_on_drop: false }`
[INFO] [stderr]     Checking regex v1.5.5
[INFO] [stderr]     Checking serde v1.0.129
[INFO] [stderr]     Checking argh v0.1.5
[INFO] [stdout] error[E0282]: type annotations needed
[INFO] [stdout]    --> /opt/rustwide/cargo-home/registry/src/index.crates.io-6f17d22bba15001f/regex-1.5.5/src/exec.rs:848:13
[INFO] [stdout]     |
[INFO] [stdout] 848 | /             match dfa::Fsm::reverse(
[INFO] [stdout] 849 | |                 &self.ro.dfa_reverse,
[INFO] [stdout] 850 | |                 self.cache.value(),
[INFO] [stdout] 851 | |                 false,
[INFO] [stdout] ...   |
[INFO] [stdout] 862 | |                 Quit => return Some(Quit),
[INFO] [stdout] 863 | |             };
[INFO] [stdout]     | |_____________^ cannot infer type
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0282`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `regex` (lib) due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "a4aa3e13dcc95b32d41292b897b31bf73b802a8052380c48ef81174119fb2be9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a4aa3e13dcc95b32d41292b897b31bf73b802a8052380c48ef81174119fb2be9", kill_on_drop: false }`
[INFO] [stdout] a4aa3e13dcc95b32d41292b897b31bf73b802a8052380c48ef81174119fb2be9