[INFO] cloning repository https://github.com/Bravo555/category-theory-for-programmers
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Bravo555/category-theory-for-programmers" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBravo555%2Fcategory-theory-for-programmers", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBravo555%2Fcategory-theory-for-programmers'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 76332543a5ef9b6acf5d5991f5c387a682aa2840
[INFO] checking Bravo555/category-theory-for-programmers/76332543a5ef9b6acf5d5991f5c387a682aa2840 against try#c387b04bf028733cd561d62128c8a5eee4bc1458+rustflags=-Dtail_expr_drop_order for pr-130930
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBravo555%2Fcategory-theory-for-programmers" "/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/Bravo555/category-theory-for-programmers on toolchain c387b04bf028733cd561d62128c8a5eee4bc1458
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+c387b04bf028733cd561d62128c8a5eee4bc1458" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Bravo555/category-theory-for-programmers
[INFO] finished tweaking git repo https://github.com/Bravo555/category-theory-for-programmers
[INFO] tweaked toml for git repo https://github.com/Bravo555/category-theory-for-programmers written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/Bravo555/category-theory-for-programmers 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" "+c387b04bf028733cd561d62128c8a5eee4bc1458" "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@sha256:6252d7ea7fb8caaf7af6d800c5fb250a9cd862b9a7f9508afb3c54fa7fe1102e" "/opt/rustwide/cargo-home/bin/cargo" "+c387b04bf028733cd561d62128c8a5eee4bc1458" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5da3fc5d48ebceab9b0e571469e78dba5b26da5af51afe5e2d8fcca107fb1bdb
[INFO] running `Command { std: "docker" "start" "-a" "5da3fc5d48ebceab9b0e571469e78dba5b26da5af51afe5e2d8fcca107fb1bdb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5da3fc5d48ebceab9b0e571469e78dba5b26da5af51afe5e2d8fcca107fb1bdb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5da3fc5d48ebceab9b0e571469e78dba5b26da5af51afe5e2d8fcca107fb1bdb", kill_on_drop: false }`
[INFO] [stdout] 5da3fc5d48ebceab9b0e571469e78dba5b26da5af51afe5e2d8fcca107fb1bdb
[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 -Dtail_expr_drop_order" "-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@sha256:6252d7ea7fb8caaf7af6d800c5fb250a9cd862b9a7f9508afb3c54fa7fe1102e" "/opt/rustwide/cargo-home/bin/cargo" "+c387b04bf028733cd561d62128c8a5eee4bc1458" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c3057d506de4d9441e243f12715e9de46a70138d105873dba2b019ce90eed27a
[INFO] running `Command { std: "docker" "start" "-a" "c3057d506de4d9441e243f12715e9de46a70138d105873dba2b019ce90eed27a", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.85
[INFO] [stderr]    Compiling getrandom v0.2.2
[INFO] [stderr]     Checking ppv-lite86 v0.2.10
[INFO] [stderr]     Checking rand_core v0.6.1
[INFO] [stderr]     Checking rand_chacha v0.3.0
[INFO] [stderr]     Checking rand v0.8.3
[INFO] [stderr]     Checking excercises v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: function `ret` is never used
[INFO] [stdout]  --> src/bin/ch4.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn ret<A>(a: A) -> Optional<A> {
[INFO] [stdout]   |    ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `ret` is never used
[INFO] [stdout]  --> src/bin/ch4.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn ret<A>(a: A) -> Optional<A> {
[INFO] [stdout]   |    ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.06s
[INFO] running `Command { std: "docker" "inspect" "c3057d506de4d9441e243f12715e9de46a70138d105873dba2b019ce90eed27a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c3057d506de4d9441e243f12715e9de46a70138d105873dba2b019ce90eed27a", kill_on_drop: false }`
[INFO] [stdout] c3057d506de4d9441e243f12715e9de46a70138d105873dba2b019ce90eed27a