[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#7014e13d5becc920d4bea3cd87942c8a13d359bf+rustflags=-Dtail_expr_drop_order for pr-129864
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBravo555%2Fcategory-theory-for-programmers" "/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/Bravo555/category-theory-for-programmers on toolchain 7014e13d5becc920d4bea3cd87942c8a13d359bf
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+7014e13d5becc920d4bea3cd87942c8a13d359bf" "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-0-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" "+7014e13d5becc920d4bea3cd87942c8a13d359bf" "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:ceb6ea022f8a89cebbe621bb4987e73a935bd40dfbb726f832cfff4742a5b95a" "/opt/rustwide/cargo-home/bin/cargo" "+7014e13d5becc920d4bea3cd87942c8a13d359bf" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e47c2b1090b74b6bf64c526026665356323c7c05b1a44ac78338d77539040cb9
[INFO] running `Command { std: "docker" "start" "-a" "e47c2b1090b74b6bf64c526026665356323c7c05b1a44ac78338d77539040cb9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e47c2b1090b74b6bf64c526026665356323c7c05b1a44ac78338d77539040cb9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e47c2b1090b74b6bf64c526026665356323c7c05b1a44ac78338d77539040cb9", kill_on_drop: false }`
[INFO] [stdout] e47c2b1090b74b6bf64c526026665356323c7c05b1a44ac78338d77539040cb9
[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 -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:ceb6ea022f8a89cebbe621bb4987e73a935bd40dfbb726f832cfff4742a5b95a" "/opt/rustwide/cargo-home/bin/cargo" "+7014e13d5becc920d4bea3cd87942c8a13d359bf" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 33a0961f749558ff1a5eeb1f3a9ce27a7ae86dfa872c4963b1842dfce77803ea
[INFO] running `Command { std: "docker" "start" "-a" "33a0961f749558ff1a5eeb1f3a9ce27a7ae86dfa872c4963b1842dfce77803ea", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.85
[INFO] [stderr]     Checking getrandom v0.2.2
[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: 1 warning emitted
[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] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.39s
[INFO] running `Command { std: "docker" "inspect" "33a0961f749558ff1a5eeb1f3a9ce27a7ae86dfa872c4963b1842dfce77803ea", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "33a0961f749558ff1a5eeb1f3a9ce27a7ae86dfa872c4963b1842dfce77803ea", kill_on_drop: false }`
[INFO] [stdout] 33a0961f749558ff1a5eeb1f3a9ce27a7ae86dfa872c4963b1842dfce77803ea