[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 against try#45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4 for pr-83744
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBravo555%2Fcategory-theory-for-programmers" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Bravo555/category-theory-for-programmers on toolchain 45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "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-4/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: "/workspace/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4bf26f7cf3edfc90f8e9682bcc33924e07305ec6823dd3028a5421b6b062f56c
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "4bf26f7cf3edfc90f8e9682bcc33924e07305ec6823dd3028a5421b6b062f56c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4bf26f7cf3edfc90f8e9682bcc33924e07305ec6823dd3028a5421b6b062f56c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4bf26f7cf3edfc90f8e9682bcc33924e07305ec6823dd3028a5421b6b062f56c", kill_on_drop: false }`
[INFO] [stdout] 4bf26f7cf3edfc90f8e9682bcc33924e07305ec6823dd3028a5421b6b062f56c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 0277b4447e03db7bff0b1a970a09700c78dad63b690a002b215aa2f39634d534
[INFO] running `Command { std: "docker" "start" "-a" "0277b4447e03db7bff0b1a970a09700c78dad63b690a002b215aa2f39634d534", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.85
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking ppv-lite86 v0.2.10
[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 is never used: `ret`
[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 is never used: `ret`
[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 [unoptimized + debuginfo] target(s) in 7.53s
[INFO] running `Command { std: "docker" "inspect" "0277b4447e03db7bff0b1a970a09700c78dad63b690a002b215aa2f39634d534", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0277b4447e03db7bff0b1a970a09700c78dad63b690a002b215aa2f39634d534", kill_on_drop: false }`
[INFO] [stdout] 0277b4447e03db7bff0b1a970a09700c78dad63b690a002b215aa2f39634d534