[INFO] updating cached repository https://github.com/sprengvogel/rust-collatz
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3f652b6e330212961dbbb905adf49d856155107f
[INFO] checking sprengvogel/rust-collatz against master#e22b61bff0bdd08be7665607cb7be3748c8a35d2 for pr-74627
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsprengvogel%2Frust-collatz" "/workspace/builds/worker-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sprengvogel/rust-collatz on toolchain e22b61bff0bdd08be7665607cb7be3748c8a35d2
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+e22b61bff0bdd08be7665607cb7be3748c8a35d2" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sprengvogel/rust-collatz
[INFO] finished tweaking git repo https://github.com/sprengvogel/rust-collatz
[INFO] tweaked toml for git repo https://github.com/sprengvogel/rust-collatz written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/sprengvogel/rust-collatz already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+e22b61bff0bdd08be7665607cb7be3748c8a35d2" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+e22b61bff0bdd08be7665607cb7be3748c8a35d2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 66cd3e7969ea832ae83dab0b0f4d5dafaf5dd57d58e3c425b0b05a983cee4702
[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" "66cd3e7969ea832ae83dab0b0f4d5dafaf5dd57d58e3c425b0b05a983cee4702", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "66cd3e7969ea832ae83dab0b0f4d5dafaf5dd57d58e3c425b0b05a983cee4702", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "66cd3e7969ea832ae83dab0b0f4d5dafaf5dd57d58e3c425b0b05a983cee4702", kill_on_drop: false }`
[INFO] [stdout] 66cd3e7969ea832ae83dab0b0f4d5dafaf5dd57d58e3c425b0b05a983cee4702
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+e22b61bff0bdd08be7665607cb7be3748c8a35d2" "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] 76f52c0807d19c46fb72a86d00461076f359635da831c9b1183de4deaef72a72
[INFO] running `Command { std: "docker" "start" "-a" "76f52c0807d19c46fb72a86d00461076f359635da831c9b1183de4deaef72a72", kill_on_drop: false }`
[INFO] [stderr]    Compiling num-traits v0.2.6
[INFO] [stderr]     Checking num-integer v0.1.39
[INFO] [stderr]     Checking num-complex v0.2.1
[INFO] [stderr]     Checking num-bigint v0.2.1
[INFO] [stderr]     Checking num-iter v0.1.37
[INFO] [stderr]     Checking num-rational v0.2.1
[INFO] [stderr]     Checking num v0.2.0
[INFO] [stderr]     Checking collatz v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: function is never used: `do_collatz_without_overflow_check`
[INFO] [stdout]   --> src/main.rs:58:4
[INFO] [stdout]    |
[INFO] [stdout] 58 | fn do_collatz_without_overflow_check(mut x: u64) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `do_collatz_with_bigints`
[INFO] [stdout]   --> src/main.rs:75:4
[INFO] [stdout]    |
[INFO] [stdout] 75 | fn do_collatz_with_bigints(mut x: BigUint) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 8.44s
[INFO] running `Command { std: "docker" "inspect" "76f52c0807d19c46fb72a86d00461076f359635da831c9b1183de4deaef72a72", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "76f52c0807d19c46fb72a86d00461076f359635da831c9b1183de4deaef72a72", kill_on_drop: false }`
[INFO] [stdout] 76f52c0807d19c46fb72a86d00461076f359635da831c9b1183de4deaef72a72