[INFO] cloning repository https://github.com/cronik/rusty-maze
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/cronik/rusty-maze" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcronik%2Frusty-maze", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcronik%2Frusty-maze'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 77ea60e11aef80abfad3f10093241ce43eb27377
[INFO] checking cronik/rusty-maze against master#ceab6128fa48a616bfd3e3adf4bc80133b8ee223 for no-never-type-fallback
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcronik%2Frusty-maze" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/cronik/rusty-maze on toolchain ceab6128fa48a616bfd3e3adf4bc80133b8ee223
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/cronik/rusty-maze
[INFO] finished tweaking git repo https://github.com/cronik/rusty-maze
[INFO] tweaked toml for git repo https://github.com/cronik/rusty-maze written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/cronik/rusty-maze 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" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] de75d52c7465a3922d8f0dfa1e2f679bfdc518423b3036f29d10ced7319d08c5
[INFO] running `Command { std: "docker" "start" "-a" "de75d52c7465a3922d8f0dfa1e2f679bfdc518423b3036f29d10ced7319d08c5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "de75d52c7465a3922d8f0dfa1e2f679bfdc518423b3036f29d10ced7319d08c5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "de75d52c7465a3922d8f0dfa1e2f679bfdc518423b3036f29d10ced7319d08c5", kill_on_drop: false }`
[INFO] [stdout] de75d52c7465a3922d8f0dfa1e2f679bfdc518423b3036f29d10ced7319d08c5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8bd75971452e1846e690adf315a1b33d194375551144a5d4732f7eab39616c79
[INFO] running `Command { std: "docker" "start" "-a" "8bd75971452e1846e690adf315a1b33d194375551144a5d4732f7eab39616c79", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.34
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.82
[INFO] [stderr]    Compiling libc v0.2.112
[INFO] [stderr]    Compiling version_check v0.9.3
[INFO] [stderr]    Compiling serde_derive v1.0.132
[INFO] [stderr]     Checking unicode-width v0.1.9
[INFO] [stderr]    Compiling unicode-segmentation v1.8.0
[INFO] [stderr]    Compiling serde v1.0.132
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking ppv-lite86 v0.2.15
[INFO] [stderr]     Checking numtoa v0.1.0
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]     Checking base64 v0.13.0
[INFO] [stderr]    Compiling quote v1.0.10
[INFO] [stderr]     Checking getrandom v0.2.3
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking termion v1.5.6
[INFO] [stderr]     Checking clap v2.34.0
[INFO] [stderr]     Checking rand_core v0.6.3
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking rand v0.8.4
[INFO] [stderr]    Compiling structopt-derive v0.4.18
[INFO] [stderr]    Compiling thiserror-impl v1.0.30
[INFO] [stderr]     Checking thiserror v1.0.30
[INFO] [stderr]     Checking structopt v0.3.25
[INFO] [stderr]     Checking ron v0.6.6
[INFO] [stderr]     Checking rusty_maze v0.2.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/disjset.rs:11:10
[INFO] [stdout]    |
[INFO] [stdout] 11 |     Same(usize),
[INFO] [stdout]    |     ---- ^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     field in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 11 |     Same(()),
[INFO] [stdout]    |          ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `lookup` and `len` are never used
[INFO] [stdout]   --> src/disjset.rs:49:12
[INFO] [stdout]    |
[INFO] [stdout] 15 | impl DisjSet {
[INFO] [stdout]    | ------------ methods in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 49 |     pub fn lookup(&self, c: usize) -> usize {
[INFO] [stdout]    |            ^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 57 |     pub fn len(&self) -> usize {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/disjset.rs:11:10
[INFO] [stdout]    |
[INFO] [stdout] 11 |     Same(usize),
[INFO] [stdout]    |     ---- ^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     field in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 11 |     Same(()),
[INFO] [stdout]    |          ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `len` is never used
[INFO] [stdout]   --> src/disjset.rs:57:12
[INFO] [stdout]    |
[INFO] [stdout] 15 | impl DisjSet {
[INFO] [stdout]    | ------------ method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 57 |     pub fn len(&self) -> usize {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 7.61s
[INFO] running `Command { std: "docker" "inspect" "8bd75971452e1846e690adf315a1b33d194375551144a5d4732f7eab39616c79", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8bd75971452e1846e690adf315a1b33d194375551144a5d4732f7eab39616c79", kill_on_drop: false }`
[INFO] [stdout] 8bd75971452e1846e690adf315a1b33d194375551144a5d4732f7eab39616c79