[INFO] cloning repository https://github.com/UsamaHameed/rustlings-solutions
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/UsamaHameed/rustlings-solutions" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUsamaHameed%2Frustlings-solutions", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUsamaHameed%2Frustlings-solutions'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ed22f2103bb6a85db5939d1f165d334fa2286432
[INFO] checking UsamaHameed/rustlings-solutions against master#385fa9d845dd326c6bbfd58c22244215e431948a for never-type-fallback-to-never
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUsamaHameed%2Frustlings-solutions" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/UsamaHameed/rustlings-solutions 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/UsamaHameed/rustlings-solutions
[INFO] finished tweaking git repo https://github.com/UsamaHameed/rustlings-solutions
[INFO] tweaked toml for git repo https://github.com/UsamaHameed/rustlings-solutions written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/UsamaHameed/rustlings-solutions 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]  Downloading crates ...
[INFO] [stderr]   Downloaded predicates v1.0.1
[INFO] [stderr]   Downloaded mio-extras v2.0.5
[INFO] [stderr]   Downloaded predicates-core v1.0.0
[INFO] [stderr]   Downloaded notify v4.0.15
[INFO] [stderr]   Downloaded normalize-line-endings v0.2.2
[INFO] [stderr]   Downloaded predicates-tree v1.0.0
[INFO] [stderr]   Downloaded float-cmp v0.4.0
[INFO] [stderr]   Downloaded console v0.7.7
[INFO] [stderr]   Downloaded serde_derive v1.0.92
[INFO] [stderr]   Downloaded ryu v0.2.8
[INFO] [stderr]   Downloaded serde_json v1.0.39
[INFO] [stderr]   Downloaded console v0.8.0
[INFO] [stderr]   Downloaded indicatif v0.10.3
[INFO] [stderr]   Downloaded filetime v0.2.5
[INFO] [stderr]   Downloaded inotify v0.7.0
[INFO] [stderr]   Downloaded serde v1.0.92
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] 49f37c7f793d8682e10d941084ed0cd8cd54459832436ae097f100d2251a0f60
[INFO] running `Command { std: "docker" "start" "-a" "49f37c7f793d8682e10d941084ed0cd8cd54459832436ae097f100d2251a0f60", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "49f37c7f793d8682e10d941084ed0cd8cd54459832436ae097f100d2251a0f60", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "49f37c7f793d8682e10d941084ed0cd8cd54459832436ae097f100d2251a0f60", kill_on_drop: false }`
[INFO] [stdout] 49f37c7f793d8682e10d941084ed0cd8cd54459832436ae097f100d2251a0f60
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] 766fe7dbe095ac69cd6af7f70a9698ff617b61c071b04271723f7b49e9340547
[INFO] running `Command { std: "docker" "start" "-a" "766fe7dbe095ac69cd6af7f70a9698ff617b61c071b04271723f7b49e9340547", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.58
[INFO] [stderr]    Compiling autocfg v0.1.4
[INFO] [stderr]     Checking rand_core v0.4.0
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]     Checking lazy_static v1.3.0
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]    Compiling regex v1.1.6
[INFO] [stderr]     Checking ucd-util v0.1.3
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]     Checking regex-syntax v0.6.6
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]     Checking utf8-ranges v1.0.2
[INFO] [stderr]    Compiling serde v1.0.92
[INFO] [stderr]     Checking aho-corasick v0.7.3
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking rand_hc v0.1.0
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]     Checking rand_xorshift v0.1.1
[INFO] [stderr]     Checking rand_isaac v0.1.1
[INFO] [stderr]     Checking rand_jitter v0.1.4
[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 lock_api v0.2.0
[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 termios v0.3.1
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]     Checking bitflags v1.0.4
[INFO] [stderr]     Checking inotify-sys v0.1.3
[INFO] [stderr]     Checking atty v0.2.11
[INFO] [stderr]     Checking predicates-core v1.0.0
[INFO] [stderr]     Checking same-file v1.0.4
[INFO] [stderr]     Checking mio v0.6.19
[INFO] [stderr]     Checking lazycell v1.2.1
[INFO] [stderr]     Checking inotify v0.7.0
[INFO] [stderr]     Checking walkdir v2.2.7
[INFO] [stderr]     Checking float-cmp v0.4.0
[INFO] [stderr]     Checking number_prefix v0.2.8
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking filetime v0.2.5
[INFO] [stderr]     Checking normalize-line-endings v0.2.2
[INFO] [stderr]     Checking predicates-tree v1.0.0
[INFO] [stderr]     Checking clap v2.33.0
[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 console v0.7.7
[INFO] [stderr]     Checking predicates v1.0.1
[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 escargot v0.4.0
[INFO] [stderr]     Checking assert_cmd v0.11.1
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 27.88s
[INFO] running `Command { std: "docker" "inspect" "766fe7dbe095ac69cd6af7f70a9698ff617b61c071b04271723f7b49e9340547", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "766fe7dbe095ac69cd6af7f70a9698ff617b61c071b04271723f7b49e9340547", kill_on_drop: false }`
[INFO] [stdout] 766fe7dbe095ac69cd6af7f70a9698ff617b61c071b04271723f7b49e9340547
[INFO] checking UsamaHameed/rustlings-solutions against try#2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2 for never-type-fallback-to-never
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUsamaHameed%2Frustlings-solutions" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/UsamaHameed/rustlings-solutions 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/UsamaHameed/rustlings-solutions
[INFO] finished tweaking git repo https://github.com/UsamaHameed/rustlings-solutions
[INFO] tweaked toml for git repo https://github.com/UsamaHameed/rustlings-solutions written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/UsamaHameed/rustlings-solutions 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] c53629d271d80504125635267f5cbef1a832c7db313589cc14a78401b866f74b
[INFO] running `Command { std: "docker" "start" "-a" "c53629d271d80504125635267f5cbef1a832c7db313589cc14a78401b866f74b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c53629d271d80504125635267f5cbef1a832c7db313589cc14a78401b866f74b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c53629d271d80504125635267f5cbef1a832c7db313589cc14a78401b866f74b", kill_on_drop: false }`
[INFO] [stdout] c53629d271d80504125635267f5cbef1a832c7db313589cc14a78401b866f74b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] a1f43de3f2eb4dd368cedd8007a22e196c8bb3ba062a93eb0178029952ed9e8f
[INFO] running `Command { std: "docker" "start" "-a" "a1f43de3f2eb4dd368cedd8007a22e196c8bb3ba062a93eb0178029952ed9e8f", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.58
[INFO] [stderr]    Compiling autocfg v0.1.4
[INFO] [stderr]     Checking rand_core v0.4.0
[INFO] [stderr]     Checking cfg-if v0.1.9
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling memchr v2.2.0
[INFO] [stderr]     Checking lazy_static v1.3.0
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[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 regex-syntax v0.6.6
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]     Checking utf8-ranges v1.0.2
[INFO] [stderr]    Compiling serde v1.0.92
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]     Checking aho-corasick v0.7.3
[INFO] [stderr]     Checking rand_os v0.1.3
[INFO] [stderr]     Checking rand_isaac v0.1.1
[INFO] [stderr]     Checking rand_xorshift v0.1.1
[INFO] [stderr]     Checking rand_hc v0.1.0
[INFO] [stderr]     Checking rand_jitter v0.1.4
[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]    Compiling ryu v0.2.8
[INFO] [stderr]     Checking scopeguard v1.0.0
[INFO] [stderr]     Checking smallvec v0.6.9
[INFO] [stderr]     Checking lock_api v0.2.0
[INFO] [stderr]     Checking clicolors-control v1.0.0
[INFO] [stderr]     Checking net2 v0.2.33
[INFO] [stderr]     Checking termios v0.3.1
[INFO] [stderr]     Checking iovec v0.1.2
[INFO] [stderr]     Checking bitflags v1.0.4
[INFO] [stderr]     Checking slab v0.4.2
[INFO] [stderr]     Checking inotify-sys v0.1.3
[INFO] [stderr]     Checking atty v0.2.11
[INFO] [stderr]     Checking predicates-core v1.0.0
[INFO] [stderr]     Checking same-file v1.0.4
[INFO] [stderr]     Checking lazycell v1.2.1
[INFO] [stderr]     Checking inotify v0.7.0
[INFO] [stderr]     Checking mio v0.6.19
[INFO] [stderr]     Checking walkdir v2.2.7
[INFO] [stderr]     Checking float-cmp v0.4.0
[INFO] [stderr]     Checking number_prefix v0.2.8
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking filetime v0.2.5
[INFO] [stderr]     Checking normalize-line-endings v0.2.2
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking predicates-tree v1.0.0
[INFO] [stderr]     Checking mio-extras v2.0.5
[INFO] [stderr]     Checking notify v4.0.15
[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]    Compiling serde_derive v1.0.92
[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 escargot v0.4.0
[INFO] [stderr]     Checking assert_cmd v0.11.1
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 24.21s
[INFO] running `Command { std: "docker" "inspect" "a1f43de3f2eb4dd368cedd8007a22e196c8bb3ba062a93eb0178029952ed9e8f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a1f43de3f2eb4dd368cedd8007a22e196c8bb3ba062a93eb0178029952ed9e8f", kill_on_drop: false }`
[INFO] [stdout] a1f43de3f2eb4dd368cedd8007a22e196c8bb3ba062a93eb0178029952ed9e8f