[INFO] cloning repository https://github.com/przprz/too-many-lists
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/przprz/too-many-lists" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprzprz%2Ftoo-many-lists", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprzprz%2Ftoo-many-lists'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8177291c9406e25a00ec9fd16ae97596a7a8be53
[INFO] testing przprz/too-many-lists against try#d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2 for pr-86479
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprzprz%2Ftoo-many-lists" "/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/przprz/too-many-lists on toolchain d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/przprz/too-many-lists
[INFO] finished tweaking git repo https://github.com/przprz/too-many-lists
[INFO] tweaked toml for git repo https://github.com/przprz/too-many-lists written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/przprz/too-many-lists already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2" "fetch" "--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" "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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f2bfe36f70e83490e06948b90d4b2877280a2d47d3bbac7fe5e70315459e2797
[INFO] running `Command { std: "docker" "start" "-a" "f2bfe36f70e83490e06948b90d4b2877280a2d47d3bbac7fe5e70315459e2797", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f2bfe36f70e83490e06948b90d4b2877280a2d47d3bbac7fe5e70315459e2797", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f2bfe36f70e83490e06948b90d4b2877280a2d47d3bbac7fe5e70315459e2797", kill_on_drop: false }`
[INFO] [stdout] f2bfe36f70e83490e06948b90d4b2877280a2d47d3bbac7fe5e70315459e2797
[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" "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" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f9dd8cb492a74c502d05867e2f469b7dd2cb2860456fb5e87b5f64706cfe3c03
[INFO] running `Command { std: "docker" "start" "-a" "f9dd8cb492a74c502d05867e2f469b7dd2cb2860456fb5e87b5f64706cfe3c03", kill_on_drop: false }`
[INFO] [stderr]    Compiling a-bad-stack v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: associated function is never used: `iter`
[INFO] [stdout]   --> src/second.rs:33:12
[INFO] [stdout]    |
[INFO] [stdout] 33 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/second.rs:37:12
[INFO] [stdout]    |
[INFO] [stdout] 37 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push`
[INFO] [stdout]   --> src/second.rs:41:12
[INFO] [stdout]    |
[INFO] [stdout] 41 |     pub fn push(&mut self, elem: T) -> &mut List<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `pop`
[INFO] [stdout]   --> src/second.rs:51:12
[INFO] [stdout]    |
[INFO] [stdout] 51 |     pub fn pop(&mut self) -> Option<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/fifth.rs:19:8
[INFO] [stdout]    |
[INFO] [stdout] 19 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/fifth.rs:29:12
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push_front`
[INFO] [stdout]   --> src/fifth.rs:33:12
[INFO] [stdout]    |
[INFO] [stdout] 33 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push_back`
[INFO] [stdout]   --> src/fifth.rs:48:12
[INFO] [stdout]    |
[INFO] [stdout] 48 |     pub fn push_back(&mut self, elem: T) {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_front`
[INFO] [stdout]   --> src/fifth.rs:93:12
[INFO] [stdout]    |
[INFO] [stdout] 93 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_back`
[INFO] [stdout]   --> src/fifth.rs:99:12
[INFO] [stdout]    |
[INFO] [stdout] 99 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_back_mut`
[INFO] [stdout]    --> src/fifth.rs:105:12
[INFO] [stdout]     |
[INFO] [stdout] 105 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_front_mut`
[INFO] [stdout]    --> src/fifth.rs:111:12
[INFO] [stdout]     |
[INFO] [stdout] 111 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `into_iter`
[INFO] [stdout]    --> src/fifth.rs:117:12
[INFO] [stdout]     |
[INFO] [stdout] 117 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.27s
[INFO] [stdout] warning: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "f9dd8cb492a74c502d05867e2f469b7dd2cb2860456fb5e87b5f64706cfe3c03", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f9dd8cb492a74c502d05867e2f469b7dd2cb2860456fb5e87b5f64706cfe3c03", kill_on_drop: false }`
[INFO] [stdout] f9dd8cb492a74c502d05867e2f469b7dd2cb2860456fb5e87b5f64706cfe3c03
[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" "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" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3ab229b2247512f3e33a1c5d783be9e8df4f93c10d94a5f0ffc07ca1114ad84e
[INFO] running `Command { std: "docker" "start" "-a" "3ab229b2247512f3e33a1c5d783be9e8df4f93c10d94a5f0ffc07ca1114ad84e", kill_on_drop: false }`
[INFO] [stdout] warning: associated function is never used: `iter`
[INFO] [stdout]   --> src/second.rs:33:12
[INFO] [stdout]    |
[INFO] [stdout] 33 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling a-bad-stack v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/second.rs:37:12
[INFO] [stdout]    |
[INFO] [stdout] 37 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push`
[INFO] [stdout]   --> src/second.rs:41:12
[INFO] [stdout]    |
[INFO] [stdout] 41 |     pub fn push(&mut self, elem: T) -> &mut List<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `pop`
[INFO] [stdout]   --> src/second.rs:51:12
[INFO] [stdout]    |
[INFO] [stdout] 51 |     pub fn pop(&mut self) -> Option<T> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/fifth.rs:19:8
[INFO] [stdout]    |
[INFO] [stdout] 19 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/fifth.rs:29:12
[INFO] [stdout]    |
[INFO] [stdout] 29 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push_front`
[INFO] [stdout]   --> src/fifth.rs:33:12
[INFO] [stdout]    |
[INFO] [stdout] 33 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `push_back`
[INFO] [stdout]   --> src/fifth.rs:48:12
[INFO] [stdout]    |
[INFO] [stdout] 48 |     pub fn push_back(&mut self, elem: T) {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_front`
[INFO] [stdout]   --> src/fifth.rs:93:12
[INFO] [stdout]    |
[INFO] [stdout] 93 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_back`
[INFO] [stdout]   --> src/fifth.rs:99:12
[INFO] [stdout]    |
[INFO] [stdout] 99 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_back_mut`
[INFO] [stdout]    --> src/fifth.rs:105:12
[INFO] [stdout]     |
[INFO] [stdout] 105 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `peek_front_mut`
[INFO] [stdout]    --> src/fifth.rs:111:12
[INFO] [stdout]     |
[INFO] [stdout] 111 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |            ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `into_iter`
[INFO] [stdout]    --> src/fifth.rs:117:12
[INFO] [stdout]     |
[INFO] [stdout] 117 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.75s
[INFO] running `Command { std: "docker" "inspect" "3ab229b2247512f3e33a1c5d783be9e8df4f93c10d94a5f0ffc07ca1114ad84e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3ab229b2247512f3e33a1c5d783be9e8df4f93c10d94a5f0ffc07ca1114ad84e", kill_on_drop: false }`
[INFO] [stdout] 3ab229b2247512f3e33a1c5d783be9e8df4f93c10d94a5f0ffc07ca1114ad84e
[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" "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" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+d2e9fff28e244f1ea4927194f1f9b77f93e2ffe2" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 84c24c6609f939ed2fed02e7bbbc79d7690d9ad716481f5e7ea54a9ea31e69a2
[INFO] running `Command { std: "docker" "start" "-a" "84c24c6609f939ed2fed02e7bbbc79d7690d9ad716481f5e7ea54a9ea31e69a2", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: associated function is never used: `iter`
[INFO] [stdout] running 5 tests
[INFO] [stderr]   --> src/second.rs:33:12
[INFO] [stdout] test fifth::test::basics ... ok
[INFO] [stderr]    |
[INFO] [stdout] test second::test::basics ... ok
[INFO] [stderr] 33 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout] test fifth::test::into_iter ... ok
[INFO] [stderr]    |            ^^^^
[INFO] [stdout] test fifth::test::peek ... ok
[INFO] [stderr]    |
[INFO] [stdout] test second::test::iter ... ok
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stderr] 
[INFO] [stdout] test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] warning: associated function is never used: `new`
[INFO] [stdout] 
[INFO] [stderr]   --> src/second.rs:37:12
[INFO] [stderr]    |
[INFO] [stderr] 37 |     pub fn new() -> Self {
[INFO] [stderr]    |            ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `push`
[INFO] [stderr]   --> src/second.rs:41:12
[INFO] [stderr]    |
[INFO] [stderr] 41 |     pub fn push(&mut self, elem: T) -> &mut List<T> {
[INFO] [stderr]    |            ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `pop`
[INFO] [stderr]   --> src/second.rs:51:12
[INFO] [stderr]    |
[INFO] [stderr] 51 |     pub fn pop(&mut self) -> Option<T> {
[INFO] [stderr]    |            ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `new`
[INFO] [stderr]   --> src/fifth.rs:19:8
[INFO] [stderr]    |
[INFO] [stderr] 19 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stderr]    |        ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `new`
[INFO] [stderr]   --> src/fifth.rs:29:12
[INFO] [stderr]    |
[INFO] [stderr] 29 |     pub fn new() -> Self {
[INFO] [stderr]    |            ^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `push_front`
[INFO] [stderr]   --> src/fifth.rs:33:12
[INFO] [stderr]    |
[INFO] [stderr] 33 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stderr]    |            ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `push_back`
[INFO] [stderr]   --> src/fifth.rs:48:12
[INFO] [stderr]    |
[INFO] [stderr] 48 |     pub fn push_back(&mut self, elem: T) {
[INFO] [stderr]    |            ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `peek_front`
[INFO] [stderr]   --> src/fifth.rs:93:12
[INFO] [stderr]    |
[INFO] [stderr] 93 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stderr]    |            ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `peek_back`
[INFO] [stderr]   --> src/fifth.rs:99:12
[INFO] [stderr]    |
[INFO] [stderr] 99 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stderr]    |            ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `peek_back_mut`
[INFO] [stderr]    --> src/fifth.rs:105:12
[INFO] [stderr]     |
[INFO] [stderr] 105 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |            ^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `peek_front_mut`
[INFO] [stderr]    --> src/fifth.rs:111:12
[INFO] [stderr]     |
[INFO] [stderr] 111 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |            ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: associated function is never used: `into_iter`
[INFO] [stderr]    --> src/fifth.rs:117:12
[INFO] [stderr]     |
[INFO] [stderr] 117 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stderr]     |            ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: `a-bad-stack` (lib) generated 13 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/a_bad_stack-5db3b21ae5171bc8)
[INFO] [stderr]    Doc-tests a-bad-stack
[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; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "84c24c6609f939ed2fed02e7bbbc79d7690d9ad716481f5e7ea54a9ea31e69a2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "84c24c6609f939ed2fed02e7bbbc79d7690d9ad716481f5e7ea54a9ea31e69a2", kill_on_drop: false }`
[INFO] [stdout] 84c24c6609f939ed2fed02e7bbbc79d7690d9ad716481f5e7ea54a9ea31e69a2