[INFO] updating cached repository ryota-sakamoto/rust_study
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/ryota-sakamoto/rust_study
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/ryota-sakamoto/rust_study" "work/ex/pr-59199/sources/master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7/gh/ryota-sakamoto/rust_study"`
[INFO] [stderr] Cloning into 'work/ex/pr-59199/sources/master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7/gh/ryota-sakamoto/rust_study'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/ryota-sakamoto/rust_study" "work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ryota-sakamoto/rust_study"`
[INFO] [stderr] Cloning into 'work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ryota-sakamoto/rust_study'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 5eb4f8bec1711983c25dcc199f9e5c1cb2a2aa47
[INFO] sha for GitHub repo ryota-sakamoto/rust_study: 5eb4f8bec1711983c25dcc199f9e5c1cb2a2aa47
[INFO] validating manifest of ryota-sakamoto/rust_study on toolchain master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of ryota-sakamoto/rust_study on toolchain try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing ryota-sakamoto/rust_study
[INFO] finished frobbing ryota-sakamoto/rust_study
[INFO] frobbed toml for ryota-sakamoto/rust_study written to work/ex/pr-59199/sources/master#bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7/gh/ryota-sakamoto/rust_study/Cargo.toml
[INFO] started frobbing ryota-sakamoto/rust_study
[INFO] finished frobbing ryota-sakamoto/rust_study
[INFO] frobbed toml for ryota-sakamoto/rust_study written to work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ryota-sakamoto/rust_study/Cargo.toml
[INFO] crate ryota-sakamoto/rust_study already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+bc44841ad2a2ad5f6c5e67b9e35ed8e7e71d4dc7-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/crater-raid/crater/work/local/cargo-home/bin/cargo" "+68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] checking ryota-sakamoto/rust_study against try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b for pr-59199
[INFO] running `"docker" "create" "-v" "/mnt/crater-raid/crater/work/local/target-dirs/pr-59199/worker-3/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b:/opt/crater/target:rw,Z" "-v" "/mnt/crater-raid/crater/work/ex/pr-59199/sources/try#68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b/gh/ryota-sakamoto/rust_study:/opt/crater/workdir:ro,Z" "-v" "/mnt/crater-raid/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/crater-raid/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+68fcf881bd1e4dbfc21e22f8c7a56b8a5d8e8f7b-alt" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 39248a3fb4979923368329dba2422ca8317379fe6dd3785c9666073d76e00ac0
[INFO] running `"docker" "start" "-a" "39248a3fb4979923368329dba2422ca8317379fe6dd3785c9666073d76e00ac0"`
[INFO] [stderr]     Checking rust_test v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused macro definition
[INFO] [stderr]   --> src/list.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | / macro_rules! list {
[INFO] [stderr] 54 | |     ($($n: expr),*) => {
[INFO] [stderr] 55 | |         {
[INFO] [stderr] 56 | |             let mut list = List::empty_list();
[INFO] [stderr] ...  |
[INFO] [stderr] 74 | |     };
[INFO] [stderr] 75 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_macros)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused macro definition
[INFO] [stderr]   --> src/list.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | / macro_rules! list {
[INFO] [stderr] 54 | |     ($($n: expr),*) => {
[INFO] [stderr] 55 | |         {
[INFO] [stderr] 56 | |             let mut list = List::empty_list();
[INFO] [stderr] ...  |
[INFO] [stderr] 74 | |     };
[INFO] [stderr] 75 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_macros)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `call`
[INFO] [stderr]  --> src/module.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | pub fn call() {
[INFO] [stderr]   | ^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `List`
[INFO] [stderr]  --> src/list.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | pub enum List<T: Debug> {
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `empty_list`
[INFO] [stderr]   --> src/list.rs:13:5
[INFO] [stderr]    |
[INFO] [stderr] 13 |     pub fn empty_list() -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `prepend`
[INFO] [stderr]   --> src/list.rs:17:5
[INFO] [stderr]    |
[INFO] [stderr] 17 |     pub fn prepend(self, t: T) -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `head`
[INFO] [stderr]   --> src/list.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn head(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `last`
[INFO] [stderr]   --> src/list.rs:31:5
[INFO] [stderr]    |
[INFO] [stderr] 31 |     pub fn last(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `is_empty`
[INFO] [stderr]   --> src/list.rs:44:5
[INFO] [stderr]    |
[INFO] [stderr] 44 |     fn is_empty(&self) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `tailrec`
[INFO] [stderr]   --> src/list.rs:87:1
[INFO] [stderr]    |
[INFO] [stderr] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:27:26
[INFO] [stderr]    |
[INFO] [stderr] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(non_shorthand_field_patterns)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:26
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:42
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                          -----^^^^^^^^^
[INFO] [stderr]    |                                          |
[INFO] [stderr]    |                                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:22
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                      -----^^^^^^^^^
[INFO] [stderr]    |                      |
[INFO] [stderr]    |                      help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:38
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                      -----^^^^^^^^^
[INFO] [stderr]    |                                      |
[INFO] [stderr]    |                                      help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `call`
[INFO] [stderr]  --> src/module.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | pub fn call() {
[INFO] [stderr]   | ^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `List`
[INFO] [stderr]  --> src/list.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | pub enum List<T: Debug> {
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `empty_list`
[INFO] [stderr]   --> src/list.rs:13:5
[INFO] [stderr]    |
[INFO] [stderr] 13 |     pub fn empty_list() -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `prepend`
[INFO] [stderr]   --> src/list.rs:17:5
[INFO] [stderr]    |
[INFO] [stderr] 17 |     pub fn prepend(self, t: T) -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `head`
[INFO] [stderr]   --> src/list.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn head(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `last`
[INFO] [stderr]   --> src/list.rs:31:5
[INFO] [stderr]    |
[INFO] [stderr] 31 |     pub fn last(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `is_empty`
[INFO] [stderr]   --> src/list.rs:44:5
[INFO] [stderr]    |
[INFO] [stderr] 44 |     fn is_empty(&self) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `tailrec`
[INFO] [stderr]   --> src/list.rs:87:1
[INFO] [stderr]    |
[INFO] [stderr] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:27:26
[INFO] [stderr]    |
[INFO] [stderr] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(non_shorthand_field_patterns)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:26
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:42
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                          -----^^^^^^^^^
[INFO] [stderr]    |                                          |
[INFO] [stderr]    |                                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:22
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                      -----^^^^^^^^^
[INFO] [stderr]    |                      |
[INFO] [stderr]    |                      help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:38
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                      -----^^^^^^^^^
[INFO] [stderr]    |                                      |
[INFO] [stderr]    |                                      help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: unused macro definition
[INFO] [stderr]   --> src/list.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | / macro_rules! list {
[INFO] [stderr] 54 | |     ($($n: expr),*) => {
[INFO] [stderr] 55 | |         {
[INFO] [stderr] 56 | |             let mut list = List::empty_list();
[INFO] [stderr] ...  |
[INFO] [stderr] 74 | |     };
[INFO] [stderr] 75 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_macros)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused macro definition
[INFO] [stderr]   --> src/list.rs:53:1
[INFO] [stderr]    |
[INFO] [stderr] 53 | / macro_rules! list {
[INFO] [stderr] 54 | |     ($($n: expr),*) => {
[INFO] [stderr] 55 | |         {
[INFO] [stderr] 56 | |             let mut list = List::empty_list();
[INFO] [stderr] ...  |
[INFO] [stderr] 74 | |     };
[INFO] [stderr] 75 | | }
[INFO] [stderr]    | |_^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_macros)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `head`
[INFO] [stderr]   --> src/list.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn head(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `last`
[INFO] [stderr]   --> src/list.rs:31:5
[INFO] [stderr]    |
[INFO] [stderr] 31 |     pub fn last(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `is_empty`
[INFO] [stderr]   --> src/list.rs:44:5
[INFO] [stderr]    |
[INFO] [stderr] 44 |     fn is_empty(&self) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `tailrec`
[INFO] [stderr]   --> src/list.rs:87:1
[INFO] [stderr]    |
[INFO] [stderr] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:27:26
[INFO] [stderr]    |
[INFO] [stderr] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(non_shorthand_field_patterns)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:26
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:42
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                          -----^^^^^^^^^
[INFO] [stderr]    |                                          |
[INFO] [stderr]    |                                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:22
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                      -----^^^^^^^^^
[INFO] [stderr]    |                      |
[INFO] [stderr]    |                      help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:38
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                      -----^^^^^^^^^
[INFO] [stderr]    |                                      |
[INFO] [stderr]    |                                      help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `head`
[INFO] [stderr]   --> src/list.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn head(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(dead_code)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `last`
[INFO] [stderr]   --> src/list.rs:31:5
[INFO] [stderr]    |
[INFO] [stderr] 31 |     pub fn last(&self) -> &T {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `is_empty`
[INFO] [stderr]   --> src/list.rs:44:5
[INFO] [stderr]    |
[INFO] [stderr] 44 |     fn is_empty(&self) -> bool {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `tailrec`
[INFO] [stderr]   --> src/list.rs:87:1
[INFO] [stderr]    |
[INFO] [stderr] 87 | fn tailrec<T: Debug>(list: &List<T>) {
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:27:26
[INFO] [stderr]    |
[INFO] [stderr] 27 |             &List::List {head: ref head, tail: _} => head,
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(non_shorthand_field_patterns)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:26
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                          -----^^^^^^^^^
[INFO] [stderr]    |                          |
[INFO] [stderr]    |                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:34:42
[INFO] [stderr]    |
[INFO] [stderr] 34 |             &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                          -----^^^^^^^^^
[INFO] [stderr]    |                                          |
[INFO] [stderr]    |                                          help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `head:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:22
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                      -----^^^^^^^^^
[INFO] [stderr]    |                      |
[INFO] [stderr]    |                      help: remove this
[INFO] [stderr] 
[INFO] [stderr] warning: the `tail:` in this pattern is redundant
[INFO] [stderr]   --> src/list.rs:90:38
[INFO] [stderr]    |
[INFO] [stderr] 90 |         &List::List {head: ref head, tail: ref tail} => {
[INFO] [stderr]    |                                      -----^^^^^^^^^
[INFO] [stderr]    |                                      |
[INFO] [stderr]    |                                      help: remove this
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.68s
[INFO] running `"docker" "inspect" "39248a3fb4979923368329dba2422ca8317379fe6dd3785c9666073d76e00ac0"`
[INFO] running `"docker" "rm" "-f" "39248a3fb4979923368329dba2422ca8317379fe6dd3785c9666073d76e00ac0"`
[INFO] [stdout] 39248a3fb4979923368329dba2422ca8317379fe6dd3785c9666073d76e00ac0