[INFO] cloning repository https://github.com/tsoding/rust-doubly-linked-list
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tsoding/rust-doubly-linked-list" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftsoding%2Frust-doubly-linked-list", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftsoding%2Frust-doubly-linked-list'...
[INFO] [stderr] /workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftsoding%2Frust-doubly-linked-list: No space left on device
[WARN] Retrying crate fetch in 3 seconds (attempt 1)
[INFO] cloning repository https://github.com/tsoding/rust-doubly-linked-list
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tsoding/rust-doubly-linked-list" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftsoding%2Frust-doubly-linked-list", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftsoding%2Frust-doubly-linked-list'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 276006134a2b3010bc6fe3fef479f6c43d453f74
[INFO] checking tsoding/rust-doubly-linked-list against master#8321f00bf4a5f25cad5ec8861c5469afe6e0ce8b for pr-133925
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftsoding%2Frust-doubly-linked-list" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/tsoding/rust-doubly-linked-list on toolchain 8321f00bf4a5f25cad5ec8861c5469afe6e0ce8b
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+8321f00bf4a5f25cad5ec8861c5469afe6e0ce8b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/tsoding/rust-doubly-linked-list
[INFO] finished tweaking git repo https://github.com/tsoding/rust-doubly-linked-list
[INFO] tweaked toml for git repo https://github.com/tsoding/rust-doubly-linked-list written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/tsoding/rust-doubly-linked-list 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" "+8321f00bf4a5f25cad5ec8861c5469afe6e0ce8b" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:c80049f3b88b82089a44e0f06d0d6029d44b96b7257e55a1cd63dbc9f4c33334" "/opt/rustwide/cargo-home/bin/cargo" "+8321f00bf4a5f25cad5ec8861c5469afe6e0ce8b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b656c2e42574e1e59e3e9915598b5c8ad4c39fd043d938ab35009303cad5c3f5
[INFO] running `Command { std: "docker" "start" "-a" "b656c2e42574e1e59e3e9915598b5c8ad4c39fd043d938ab35009303cad5c3f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b656c2e42574e1e59e3e9915598b5c8ad4c39fd043d938ab35009303cad5c3f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b656c2e42574e1e59e3e9915598b5c8ad4c39fd043d938ab35009303cad5c3f5", kill_on_drop: false }`
[INFO] [stdout] b656c2e42574e1e59e3e9915598b5c8ad4c39fd043d938ab35009303cad5c3f5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:c80049f3b88b82089a44e0f06d0d6029d44b96b7257e55a1cd63dbc9f4c33334" "/opt/rustwide/cargo-home/bin/cargo" "+8321f00bf4a5f25cad5ec8861c5469afe6e0ce8b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] fef13494e2d9901e2b773578bb2500751eb59b1b34e5516fc00968b7b24b516f
[INFO] running `Command { std: "docker" "start" "-a" "fef13494e2d9901e2b773578bb2500751eb59b1b34e5516fc00968b7b24b516f", kill_on_drop: false }`
[INFO] [stderr]     Checking rust-doubly-linked-list v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:19:13
[INFO] [stdout]    |
[INFO] [stdout] 19 |         for x in self.buffer.iter() {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:19:13
[INFO] [stdout]    |
[INFO] [stdout] 19 |         for x in self.buffer.iter() {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `pop_back` is never used
[INFO] [stdout]    --> src/main.rs:123:8
[INFO] [stdout]     |
[INFO] [stdout] 77  | impl<T: Clone + Debug> Deque<T> {
[INFO] [stdout]     | ------------------------------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 123 |     fn pop_back(&mut self, memory: &mut Memory<Node<T>>) {
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `pop_back` is never used
[INFO] [stdout]    --> src/main.rs:123:8
[INFO] [stdout]     |
[INFO] [stdout] 77  | impl<T: Clone + Debug> Deque<T> {
[INFO] [stdout]     | ------------------------------- method in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 123 |     fn pop_back(&mut self, memory: &mut Memory<Node<T>>) {
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.10s
[INFO] running `Command { std: "docker" "inspect" "fef13494e2d9901e2b773578bb2500751eb59b1b34e5516fc00968b7b24b516f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fef13494e2d9901e2b773578bb2500751eb59b1b34e5516fc00968b7b24b516f", kill_on_drop: false }`
[INFO] [stdout] fef13494e2d9901e2b773578bb2500751eb59b1b34e5516fc00968b7b24b516f