[INFO] cloning repository https://github.com/shide1989/rustlings_answers
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/shide1989/rustlings_answers" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshide1989%2Frustlings_answers", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshide1989%2Frustlings_answers'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f275a583cab053fec671301a1ff8f26f43540ae8
[INFO] checking shide1989/rustlings_answers against try#c86ec274072509d26d0ee52682a0c94ed012ed89 for pr-153027
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fshide1989%2Frustlings_answers" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/shide1989/rustlings_answers
[INFO] finished tweaking git repo https://github.com/shide1989/rustlings_answers
[INFO] tweaked toml for git repo https://github.com/shide1989/rustlings_answers written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/shide1989/rustlings_answers on toolchain c86ec274072509d26d0ee52682a0c94ed012ed89
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+c86ec274072509d26d0ee52682a0c94ed012ed89" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+c86ec274072509d26d0ee52682a0c94ed012ed89" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+c86ec274072509d26d0ee52682a0c94ed012ed89" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+c86ec274072509d26d0ee52682a0c94ed012ed89" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d733305522b425e647ca74ff3dd341ac4c308a8c75345a74b405a09c1a586e7e
[INFO] running `Command { std: "docker" "start" "-a" "d733305522b425e647ca74ff3dd341ac4c308a8c75345a74b405a09c1a586e7e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d733305522b425e647ca74ff3dd341ac4c308a8c75345a74b405a09c1a586e7e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d733305522b425e647ca74ff3dd341ac4c308a8c75345a74b405a09c1a586e7e", kill_on_drop: false }`
[INFO] [stdout] d733305522b425e647ca74ff3dd341ac4c308a8c75345a74b405a09c1a586e7e
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+c86ec274072509d26d0ee52682a0c94ed012ed89" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 7e7f3f2b8906b93d0f7fbbaf384ea51ed3a2f1c10296847396291bfedf85ac76
[INFO] running `Command { std: "docker" "start" "-a" "7e7f3f2b8906b93d0f7fbbaf384ea51ed3a2f1c10296847396291bfedf85ac76", kill_on_drop: false }`
[INFO] [stderr]     Checking exercises v0.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> exercises/23_conversions/from_str.rs:60:13
[INFO] [stdout]    |
[INFO] [stdout] 60 |         let mut u: usize;
[INFO] [stdout]    |             ----^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `threads3`
[INFO] [stdout]   --> exercises/20_threads/threads3.rs:64:2
[INFO] [stdout]    |
[INFO] [stdout] 64 | }
[INFO] [stdout]    |  ^ consider adding a `main` function to `exercises/20_threads/threads3.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "threads3") due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "7e7f3f2b8906b93d0f7fbbaf384ea51ed3a2f1c10296847396291bfedf85ac76", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7e7f3f2b8906b93d0f7fbbaf384ea51ed3a2f1c10296847396291bfedf85ac76", kill_on_drop: false }`
[INFO] [stdout] 7e7f3f2b8906b93d0f7fbbaf384ea51ed3a2f1c10296847396291bfedf85ac76