[INFO] cloning repository https://github.com/Unarbre/rustlings
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Unarbre/rustlings" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUnarbre%2Frustlings", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUnarbre%2Frustlings'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b41bb0bb06ca8f4197bc876d51cc5536d66436cb
[INFO] checking Unarbre/rustlings against master#ceab6128fa48a616bfd3e3adf4bc80133b8ee223 for no-never-type-fallback
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUnarbre%2Frustlings" "/workspace/builds/worker-5-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Unarbre/rustlings 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/Unarbre/rustlings
[INFO] finished tweaking git repo https://github.com/Unarbre/rustlings
[INFO] tweaked toml for git repo https://github.com/Unarbre/rustlings written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/Unarbre/rustlings 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] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded utf8-ranges v1.0.2
[INFO] [stderr]   Downloaded aho-corasick v0.7.3
[INFO] [stderr]   Downloaded normalize-line-endings v0.2.2
[INFO] [stderr]   Downloaded predicates-core v1.0.0
[INFO] [stderr]   Downloaded predicates v1.0.1
[INFO] [stderr]   Downloaded syn v0.15.34
[INFO] [stderr]   Downloaded regex v1.1.6
[INFO] [stderr]   Downloaded indicatif v0.10.3
[INFO] [stderr]   Downloaded lock_api v0.2.0
[INFO] [stderr]   Downloaded smallvec v0.6.9
[INFO] [stderr]   Downloaded inotify-sys v0.1.3
[INFO] [stderr]   Downloaded inotify v0.7.0
[INFO] [stderr]   Downloaded bitflags v1.0.4
[INFO] [stderr]   Downloaded treeline v0.1.0
[INFO] [stderr]   Downloaded encode_unicode v0.3.5
[INFO] [stderr]   Downloaded number_prefix v0.2.8
[INFO] [stderr]   Downloaded parking_lot_core v0.5.0
[INFO] [stderr]   Downloaded predicates-tree v1.0.0
[INFO] [stderr]   Downloaded console v0.7.7
[INFO] [stderr]   Downloaded termion v1.5.2
[INFO] [stderr]   Downloaded clicolors-control v1.0.0
[INFO] [stderr]   Downloaded console v0.8.0
[INFO] [stderr]   Downloaded parking_lot v0.8.0
[INFO] [stderr]   Downloaded iovec v0.1.2
[INFO] [stderr]   Downloaded notify v4.0.15
[INFO] [stderr]   Downloaded net2 v0.2.33
[INFO] [stderr]   Downloaded mio v0.6.19
[INFO] [stderr]   Downloaded mio-extras v2.0.5
[INFO] [stderr]   Downloaded walkdir v2.2.7
[INFO] [stderr]   Downloaded filetime v0.2.5
[INFO] [stderr]   Downloaded float-cmp v0.4.0
[INFO] [stderr]   Downloaded regex-syntax v0.6.6
[INFO] [stderr]   Downloaded assert_cmd v0.11.1
[INFO] [stderr]   Downloaded escargot v0.4.0
[INFO] [stderr]   Downloaded scopeguard v1.0.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 40e9e54a711a42717e6d3ea1442a653edf21baa47745ceffa37ca6530f84782a
[INFO] running `Command { std: "docker" "start" "-a" "40e9e54a711a42717e6d3ea1442a653edf21baa47745ceffa37ca6530f84782a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "40e9e54a711a42717e6d3ea1442a653edf21baa47745ceffa37ca6530f84782a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "40e9e54a711a42717e6d3ea1442a653edf21baa47745ceffa37ca6530f84782a", kill_on_drop: false }`
[INFO] [stdout] 40e9e54a711a42717e6d3ea1442a653edf21baa47745ceffa37ca6530f84782a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 4e539ab14984d03188666782e4f3257a9a97c8fc16024daa24db8a2b8ba2aca2
[INFO] running `Command { std: "docker" "start" "-a" "4e539ab14984d03188666782e4f3257a9a97c8fc16024daa24db8a2b8ba2aca2", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.58
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]     Checking ucd-util v0.1.3
[INFO] [stderr]    Compiling regex v1.1.6
[INFO] [stderr]     Checking utf8-ranges v1.0.2
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]    Compiling serde v1.0.92
[INFO] [stderr]    Compiling parking_lot_core v0.5.0
[INFO] [stderr]     Checking log v0.4.6
[INFO] [stderr]     Checking unicode-width v0.1.5
[INFO] [stderr]    Compiling parking_lot v0.8.0
[INFO] [stderr]     Checking smallvec v0.6.9
[INFO] [stderr]     Checking scopeguard v1.0.0
[INFO] [stderr]    Compiling ryu v0.2.8
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]     Checking bitflags v1.0.4
[INFO] [stderr]     Checking lock_api v0.2.0
[INFO] [stderr]     Checking regex-syntax v0.6.6
[INFO] [stderr]    Compiling escargot v0.4.0
[INFO] [stderr]     Checking predicates-core v1.0.0
[INFO] [stderr]     Checking lazycell v1.2.1
[INFO] [stderr]     Checking itoa v0.4.4
[INFO] [stderr]     Checking walkdir v2.2.7
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking number_prefix v0.2.8
[INFO] [stderr]     Checking float-cmp v0.4.0
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking difference v2.0.0
[INFO] [stderr]     Checking normalize-line-endings v0.2.2
[INFO] [stderr]     Checking treeline v0.1.0
[INFO] [stderr]     Checking glob v0.3.0
[INFO] [stderr]     Checking predicates-tree v1.0.0
[INFO] [stderr]     Checking aho-corasick v0.7.3
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking termios v0.3.1
[INFO] [stderr]     Checking iovec v0.1.2
[INFO] [stderr]     Checking clicolors-control v1.0.0
[INFO] [stderr]     Checking net2 v0.2.33
[INFO] [stderr]     Checking inotify-sys v0.1.3
[INFO] [stderr]     Checking atty v0.2.11
[INFO] [stderr]     Checking filetime v0.2.5
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking inotify v0.7.0
[INFO] [stderr]     Checking rand v0.6.5
[INFO] [stderr]     Checking mio v0.6.19
[INFO] [stderr]     Checking mio-extras v2.0.5
[INFO] [stderr]     Checking notify v4.0.15
[INFO] [stderr]    Compiling serde_derive v1.0.92
[INFO] [stderr]     Checking console v0.8.0
[INFO] [stderr]     Checking predicates v1.0.1
[INFO] [stderr]     Checking console v0.7.7
[INFO] [stderr]     Checking indicatif v0.10.3
[INFO] [stderr]     Checking serde_json v1.0.39
[INFO] [stderr]     Checking toml v0.4.10
[INFO] [stderr]     Checking rustlings v4.3.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking assert_cmd v0.11.1
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 6.10s
[INFO] running `Command { std: "docker" "inspect" "4e539ab14984d03188666782e4f3257a9a97c8fc16024daa24db8a2b8ba2aca2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4e539ab14984d03188666782e4f3257a9a97c8fc16024daa24db8a2b8ba2aca2", kill_on_drop: false }`
[INFO] [stdout] 4e539ab14984d03188666782e4f3257a9a97c8fc16024daa24db8a2b8ba2aca2
[INFO] checking Unarbre/rustlings against try#3a4bc97f6385a3aa300a4fd689b44350e54fd676 for no-never-type-fallback
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUnarbre%2Frustlings" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Unarbre/rustlings 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/Unarbre/rustlings
[INFO] finished tweaking git repo https://github.com/Unarbre/rustlings
[INFO] tweaked toml for git repo https://github.com/Unarbre/rustlings written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/Unarbre/rustlings 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-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 096f96d6165dfc4d93725a76ca5d6a5e6f8ff64b915a3e05721052d2e4180efa
[INFO] running `Command { std: "docker" "start" "-a" "096f96d6165dfc4d93725a76ca5d6a5e6f8ff64b915a3e05721052d2e4180efa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "096f96d6165dfc4d93725a76ca5d6a5e6f8ff64b915a3e05721052d2e4180efa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "096f96d6165dfc4d93725a76ca5d6a5e6f8ff64b915a3e05721052d2e4180efa", kill_on_drop: false }`
[INFO] [stdout] 096f96d6165dfc4d93725a76ca5d6a5e6f8ff64b915a3e05721052d2e4180efa
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 47e7bd9feb4ca171731e2afb869ecd4c38ef911c9eea8f4ba59a3c05cf7f3985
[INFO] running `Command { std: "docker" "start" "-a" "47e7bd9feb4ca171731e2afb869ecd4c38ef911c9eea8f4ba59a3c05cf7f3985", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.58
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]     Checking ucd-util v0.1.3
[INFO] [stderr]    Compiling regex v1.1.6
[INFO] [stderr]     Checking utf8-ranges v1.0.2
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]    Compiling serde v1.0.92
[INFO] [stderr]     Checking log v0.4.6
[INFO] [stderr]    Compiling parking_lot_core v0.5.0
[INFO] [stderr]     Checking unicode-width v0.1.5
[INFO] [stderr]    Compiling parking_lot v0.8.0
[INFO] [stderr]     Checking scopeguard v1.0.0
[INFO] [stderr]     Checking smallvec v0.6.9
[INFO] [stderr]    Compiling ryu v0.2.8
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]     Checking bitflags v1.0.4
[INFO] [stderr]     Checking lock_api v0.2.0
[INFO] [stderr]     Checking regex-syntax v0.6.6
[INFO] [stderr]    Compiling escargot v0.4.0
[INFO] [stderr]     Checking itoa v0.4.4
[INFO] [stderr]     Checking lazycell v1.2.1
[INFO] [stderr]     Checking predicates-core v1.0.0
[INFO] [stderr]     Checking walkdir v2.2.7
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking number_prefix v0.2.8
[INFO] [stderr]     Checking float-cmp v0.4.0
[INFO] [stderr]     Checking normalize-line-endings v0.2.2
[INFO] [stderr]     Checking treeline v0.1.0
[INFO] [stderr]     Checking vec_map v0.8.1
[INFO] [stderr]     Checking difference v2.0.0
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking glob v0.3.0
[INFO] [stderr]     Checking predicates-tree v1.0.0
[INFO] [stderr]     Checking aho-corasick v0.7.3
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking termios v0.3.1
[INFO] [stderr]     Checking iovec v0.1.2
[INFO] [stderr]     Checking net2 v0.2.33
[INFO] [stderr]     Checking clicolors-control v1.0.0
[INFO] [stderr]     Checking atty v0.2.11
[INFO] [stderr]     Checking inotify-sys v0.1.3
[INFO] [stderr]     Checking filetime v0.2.5
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking inotify v0.7.0
[INFO] [stderr]     Checking rand v0.6.5
[INFO] [stderr]     Checking mio v0.6.19
[INFO] [stderr]     Checking mio-extras v2.0.5
[INFO] [stderr]     Checking notify v4.0.15
[INFO] [stdout] error[E0282]: type annotations needed
[INFO] [stdout]    --> /opt/rustwide/cargo-home/registry/src/index.crates.io-6f17d22bba15001f/regex-1.1.6/src/exec.rs:797:13
[INFO] [stdout]     |
[INFO] [stdout] 797 | /             match dfa::Fsm::reverse(
[INFO] [stdout] 798 | |                 &self.ro.dfa_reverse,
[INFO] [stdout] 799 | |                 self.cache,
[INFO] [stdout] 800 | |                 false,
[INFO] [stdout] ...   |
[INFO] [stdout] 811 | |                 Quit => return Some(Quit),
[INFO] [stdout] 812 | |             };
[INFO] [stdout]     | |_____________^ cannot infer type
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling serde_derive v1.0.92
[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" "47e7bd9feb4ca171731e2afb869ecd4c38ef911c9eea8f4ba59a3c05cf7f3985", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "47e7bd9feb4ca171731e2afb869ecd4c38ef911c9eea8f4ba59a3c05cf7f3985", kill_on_drop: false }`
[INFO] [stdout] 47e7bd9feb4ca171731e2afb869ecd4c38ef911c9eea8f4ba59a3c05cf7f3985