[INFO] updating cached repository https://github.com/nbardiuk/mazes
[INFO] running `"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"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 888a96302611db487c41fcf8f050032ddf535b44
[INFO] checking nbardiuk/mazes against try#1a608893c03d7722effeb0058e82770bd36b4b3c for pr-66504-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnbardiuk%2Fmazes" "/workspace/builds/worker-4/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/nbardiuk/mazes on toolchain 1a608893c03d7722effeb0058e82770bd36b4b3c
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1a608893c03d7722effeb0058e82770bd36b4b3c" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/nbardiuk/mazes
[INFO] finished tweaking git repo https://github.com/nbardiuk/mazes
[INFO] tweaked toml for git repo https://github.com/nbardiuk/mazes written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/nbardiuk/mazes already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1a608893c03d7722effeb0058e82770bd36b4b3c" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"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" "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" "/opt/rustwide/cargo-home/bin/cargo" "+1a608893c03d7722effeb0058e82770bd36b4b3c" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 004ac4aa56270fcef446914020e82845ec0d7f17b552a1ac32116b275ee2aef2
[INFO] running `"docker" "start" "-a" "004ac4aa56270fcef446914020e82845ec0d7f17b552a1ac32116b275ee2aef2"`
[INFO] [stderr]     Checking svg v0.6.0
[INFO] [stderr]     Checking getrandom v0.1.12
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking rand v0.7.2
[INFO] [stderr]     Checking mazes v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused import: `Rng`
[INFO] [stderr]  --> src/binary_tree.rs:4:24
[INFO] [stderr]   |
[INFO] [stderr] 4 | use rand::{thread_rng, Rng};
[INFO] [stderr]   |                        ^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]    --> src/maze.rs:175:13
[INFO] [stderr]     |
[INFO] [stderr] 175 |         for x in 0..self.width {
[INFO] [stderr]     |             ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `BinaryTree`
[INFO] [stderr]  --> src/binary_tree.rs:6:12
[INFO] [stderr]   |
[INFO] [stderr] 6 | pub struct BinaryTree;
[INFO] [stderr]   |            ^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `on`
[INFO] [stderr]  --> src/binary_tree.rs:8:5
[INFO] [stderr]   |
[INFO] [stderr] 8 |     pub fn on(mut maze: Maze) -> Maze {
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `links`
[INFO] [stderr]   --> src/maze.rs:92:5
[INFO] [stderr]    |
[INFO] [stderr] 92 |     pub fn links(&self, cell: &Cell) -> Vec<Cell> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Rng`
[INFO] [stderr]  --> src/binary_tree.rs:4:24
[INFO] [stderr]   |
[INFO] [stderr] 4 | use rand::{thread_rng, Rng};
[INFO] [stderr]   |                        ^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]    --> src/maze.rs:175:13
[INFO] [stderr]     |
[INFO] [stderr] 175 |         for x in 0..self.width {
[INFO] [stderr]     |             ^ help: consider prefixing with an underscore: `_x`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 8.54s
[INFO] running `"docker" "inspect" "004ac4aa56270fcef446914020e82845ec0d7f17b552a1ac32116b275ee2aef2"`
[INFO] running `"docker" "rm" "-f" "004ac4aa56270fcef446914020e82845ec0d7f17b552a1ac32116b275ee2aef2"`
[INFO] [stdout] 004ac4aa56270fcef446914020e82845ec0d7f17b552a1ac32116b275ee2aef2