[INFO] updating cached repository https://github.com/christiansakai/linked_list_rust
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/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] b59f6d038c7a3a9c7cfb4a83a0103de5a7b175ce
[INFO] testing christiansakai/linked_list_rust against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fchristiansakai%2Flinked_list_rust" "work/builds/worker-6/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/christiansakai/linked_list_rust on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/christiansakai/linked_list_rust
[INFO] finished tweaking git repo https://github.com/christiansakai/linked_list_rust
[INFO] tweaked toml for git repo https://github.com/christiansakai/linked_list_rust written to work/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/christiansakai/linked_list_rust already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-6/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-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" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] c3e859a9410d86ebc83f0aa25659e74857b41354b1569d1b9072f32e78724bf1
[INFO] running `"docker" "start" "-a" "c3e859a9410d86ebc83f0aa25659e74857b41354b1569d1b9072f32e78724bf1"`
[INFO] [stderr]    Compiling linked_list_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused import: `super::*`
[INFO] [stderr]   --> src/first.rs:75:9
[INFO] [stderr]    |
[INFO] [stderr] 75 |     use super::*;
[INFO] [stderr]    |         ^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `elem`
[INFO] [stderr]   --> src/fourth.rs:51:33
[INFO] [stderr]    |
[INFO] [stderr] 51 |     pub fn pop_front(&mut self, elem: T) -> Option<T> {
[INFO] [stderr]    |                                 ^^^^ help: consider prefixing with an underscore: `_elem`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.56s
[INFO] running `"docker" "inspect" "c3e859a9410d86ebc83f0aa25659e74857b41354b1569d1b9072f32e78724bf1"`
[INFO] running `"docker" "rm" "-f" "c3e859a9410d86ebc83f0aa25659e74857b41354b1569d1b9072f32e78724bf1"`
[INFO] [stdout] c3e859a9410d86ebc83f0aa25659e74857b41354b1569d1b9072f32e78724bf1
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-6/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-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" "+1.38.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] 52737016d9a53f8ba29e0592b3406cce54786616a9f8ead0124596662b07b117
[INFO] running `"docker" "start" "-a" "52737016d9a53f8ba29e0592b3406cce54786616a9f8ead0124596662b07b117"`
[INFO] [stderr]    Compiling linked_list_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `elem`
[INFO] [stderr]   --> src/fourth.rs:51:33
[INFO] [stderr]    |
[INFO] [stderr] 51 |     pub fn pop_front(&mut self, elem: T) -> Option<T> {
[INFO] [stderr]    |                                 ^^^^ help: consider prefixing with an underscore: `_elem`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.48s
[INFO] running `"docker" "inspect" "52737016d9a53f8ba29e0592b3406cce54786616a9f8ead0124596662b07b117"`
[INFO] running `"docker" "rm" "-f" "52737016d9a53f8ba29e0592b3406cce54786616a9f8ead0124596662b07b117"`
[INFO] [stdout] 52737016d9a53f8ba29e0592b3406cce54786616a9f8ead0124596662b07b117
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-6/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-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" "+1.38.0" "test" "--frozen"`
[INFO] [stdout] 38779b6a5329b60939c84369248da62f3e25a1e562feb24e0557e438356f344a
[INFO] running `"docker" "start" "-a" "38779b6a5329b60939c84369248da62f3e25a1e562feb24e0557e438356f344a"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.00s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/linked_list_rust-cbead0b26b3d525a
[INFO] [stdout] 
[INFO] [stdout] running 3 tests
[INFO] [stdout] test first::test::basics ... ok
[INFO] [stdout] test third::test::iter ... ok
[INFO] [stdout] test third::test::basics ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/linked_list_rust-d2b6e8c0b7273871
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests linked_list_rust
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "38779b6a5329b60939c84369248da62f3e25a1e562feb24e0557e438356f344a"`
[INFO] running `"docker" "rm" "-f" "38779b6a5329b60939c84369248da62f3e25a1e562feb24e0557e438356f344a"`
[INFO] [stdout] 38779b6a5329b60939c84369248da62f3e25a1e562feb24e0557e438356f344a