[INFO] cloning repository https://github.com/ryota-sakamoto/rust_study
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ryota-sakamoto/rust_study" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fryota-sakamoto%2Frust_study", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fryota-sakamoto%2Frust_study'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5eb4f8bec1711983c25dcc199f9e5c1cb2a2aa47
[INFO] checking ryota-sakamoto/rust_study against master#1f12b9b0fdbe735968ac002792a720f0ba4faca6 for crater-rollup-uwu
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fryota-sakamoto%2Frust_study" "/workspace/builds/worker-5-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/ryota-sakamoto/rust_study on toolchain 1f12b9b0fdbe735968ac002792a720f0ba4faca6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/ryota-sakamoto/rust_study
[INFO] finished tweaking git repo https://github.com/ryota-sakamoto/rust_study
[INFO] tweaked toml for git repo https://github.com/ryota-sakamoto/rust_study written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/ryota-sakamoto/rust_study 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" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2021
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3d2173d019452ac07a1f0fe55525f8898828b1932adf9c9357b9be009d1fff1a
[INFO] running `Command { std: "docker" "start" "-a" "3d2173d019452ac07a1f0fe55525f8898828b1932adf9c9357b9be009d1fff1a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3d2173d019452ac07a1f0fe55525f8898828b1932adf9c9357b9be009d1fff1a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3d2173d019452ac07a1f0fe55525f8898828b1932adf9c9357b9be009d1fff1a", kill_on_drop: false }`
[INFO] [stdout] 3d2173d019452ac07a1f0fe55525f8898828b1932adf9c9357b9be009d1fff1a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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@sha256:923055f121b5182466d55868a8b05e67af8ba4a3a3f6bad814e953ca3cd3ac2a" "/opt/rustwide/cargo-home/bin/cargo" "+1f12b9b0fdbe735968ac002792a720f0ba4faca6" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 598e61362e9cfa6dac83fcf2b24598cb5e01474f4cd01ac74caa417c608b8af1
[INFO] running `Command { std: "docker" "start" "-a" "598e61362e9cfa6dac83fcf2b24598cb5e01474f4cd01ac74caa417c608b8af1", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2021
[INFO] [stderr]     Checking libc v0.2.39
[INFO] [stderr]     Checking rand v0.4.2
[INFO] [stderr]     Checking rust_test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused macro definition: `list`
[INFO] [stdout]   --> src/list.rs:53:14
[INFO] [stdout]    |
[INFO] [stdout] 53 | macro_rules! list {
[INFO] [stdout]    |              ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused macro definition: `list`
[INFO] [stdout]   --> src/list.rs:53:14
[INFO] [stdout]    |
[INFO] [stdout] 53 | macro_rules! list {
[INFO] [stdout]    |              ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `call` is never used
[INFO] [stdout]  --> src/module.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub fn call() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]  --> src/list.rs:4:10
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub enum List<T: Debug> {
[INFO] [stdout]   |          ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `call` is never used
[INFO] [stdout]  --> src/module.rs:1:8
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub fn call() {
[INFO] [stdout]   |        ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `List` is never used
[INFO] [stdout]  --> src/list.rs:4:10
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub enum List<T: Debug> {
[INFO] [stdout]   |          ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `empty_list`, `prepend`, `head`, `last`, and `is_empty` are never used
[INFO] [stdout]   --> src/list.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl <T: Debug> List<T> {
[INFO] [stdout]    | ----------------------- associated items in this implementation
[INFO] [stdout] 13 |     pub fn empty_list() -> List<T> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 17 |     pub fn prepend(self, t: T) -> Self {
[INFO] [stdout]    |            ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 24 |     pub fn head(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 31 |     pub fn last(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 44 |     fn is_empty(&self) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `empty_list`, `prepend`, `head`, `last`, and `is_empty` are never used
[INFO] [stdout]   --> src/list.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl <T: Debug> List<T> {
[INFO] [stdout]    | ----------------------- associated items in this implementation
[INFO] [stdout] 13 |     pub fn empty_list() -> List<T> {
[INFO] [stdout]    |            ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 17 |     pub fn prepend(self, t: T) -> Self {
[INFO] [stdout]    |            ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 24 |     pub fn head(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 31 |     pub fn last(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 44 |     fn is_empty(&self) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `tailrec` is never used
[INFO] [stdout]   --> src/list.rs:87:4
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `tailrec` is never used
[INFO] [stdout]   --> src/list.rs:87:4
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:27:26
[INFO] [stdout]    |
[INFO] [stdout] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_shorthand_field_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:26
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:27:26
[INFO] [stdout]    |
[INFO] [stdout] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_shorthand_field_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:42
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:22
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:26
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:38
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:42
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:22
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:38
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused macro definition: `list`
[INFO] [stdout]   --> src/list.rs:53:14
[INFO] [stdout]    |
[INFO] [stdout] 53 | macro_rules! list {
[INFO] [stdout]    |              ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused macro definition: `list`
[INFO] [stdout]   --> src/list.rs:53:14
[INFO] [stdout]    |
[INFO] [stdout] 53 | macro_rules! list {
[INFO] [stdout]    |              ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:78:19
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let func: Box<Fn(u64) -> u64> = Box::new(|a| a.pow(2));
[INFO] [stdout]    |                   ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let func: Box<dyn Fn(u64) -> u64> = Box::new(|a| a.pow(2));
[INFO] [stdout]    |                   +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:78:19
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let func: Box<Fn(u64) -> u64> = Box::new(|a| a.pow(2));
[INFO] [stdout]    |                   ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let func: Box<dyn Fn(u64) -> u64> = Box::new(|a| a.pow(2));
[INFO] [stdout]    |                   +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `head` and `tail` are never read
[INFO] [stdout]  --> src/list.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     List {
[INFO] [stdout]   |     ---- fields in this variant
[INFO] [stdout] 7 |         head: T,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout] 8 |         tail: Box<List<T>>,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `head`, `last`, and `is_empty` are never used
[INFO] [stdout]   --> src/list.rs:24:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl <T: Debug> List<T> {
[INFO] [stdout]    | ----------------------- methods in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 24 |     pub fn head(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 31 |     pub fn last(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 44 |     fn is_empty(&self) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `tailrec` is never used
[INFO] [stdout]   --> src/list.rs:87:4
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:27:26
[INFO] [stdout]    |
[INFO] [stdout] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_shorthand_field_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:26
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:42
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `head` and `tail` are never read
[INFO] [stdout]  --> src/list.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     List {
[INFO] [stdout]   |     ---- fields in this variant
[INFO] [stdout] 7 |         head: T,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout] 8 |         tail: Box<List<T>>,
[INFO] [stdout]   |         ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:22
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `head`, `last`, and `is_empty` are never used
[INFO] [stdout]   --> src/list.rs:24:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl <T: Debug> List<T> {
[INFO] [stdout]    | ----------------------- methods in this implementation
[INFO] [stdout] ...
[INFO] [stdout] 24 |     pub fn head(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 31 |     pub fn last(&self) -> &T {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 44 |     fn is_empty(&self) -> bool {
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:38
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `tailrec` is never used
[INFO] [stdout]   --> src/list.rs:87:4
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:27:26
[INFO] [stdout]    |
[INFO] [stdout] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_shorthand_field_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:26
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:34:42
[INFO] [stdout]    |
[INFO] [stdout] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                          ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `head:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:22
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref head`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the `tail:` in this pattern is redundant
[INFO] [stdout]   --> src/list.rs:90:38
[INFO] [stdout]    |
[INFO] [stdout] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stdout]    |                                      ^^^^^^^^^^^^^^ help: use shorthand field pattern: `ref tail`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.71s
[INFO] running `Command { std: "docker" "inspect" "598e61362e9cfa6dac83fcf2b24598cb5e01474f4cd01ac74caa417c608b8af1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "598e61362e9cfa6dac83fcf2b24598cb5e01474f4cd01ac74caa417c608b8af1", kill_on_drop: false }`
[INFO] [stdout] 598e61362e9cfa6dac83fcf2b24598cb5e01474f4cd01ac74caa417c608b8af1