[INFO] updating cached repository https://github.com/vlabo/rust_linked_list
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/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] 7acf8ae8f8b2b7cd5e6f926627917dad00b669aa
[INFO] checking vlabo/rust_linked_list against master#ba72b15666b2491415aec703a02c2364fe5e2790 for pr-71140
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvlabo%2Frust_linked_list" "/workspace/builds/worker-13/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/vlabo/rust_linked_list on toolchain ba72b15666b2491415aec703a02c2364fe5e2790
[INFO] running `"/workspace/cargo-home/bin/cargo" "+ba72b15666b2491415aec703a02c2364fe5e2790" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/vlabo/rust_linked_list
[INFO] finished tweaking git repo https://github.com/vlabo/rust_linked_list
[INFO] tweaked toml for git repo https://github.com/vlabo/rust_linked_list written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/vlabo/rust_linked_list already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+ba72b15666b2491415aec703a02c2364fe5e2790" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+ba72b15666b2491415aec703a02c2364fe5e2790" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] d0050d27a61e3fe1d4071b309c26badecf34681d68f33318528edd57731e0dc2
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "d0050d27a61e3fe1d4071b309c26badecf34681d68f33318528edd57731e0dc2"`
[INFO] [stderr]     Checking rust_linked_list v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused import: `super::List`
[INFO] [stderr]   --> src/first.rs:52:9
[INFO] [stderr]    |
[INFO] [stderr] 52 |     use super::List;
[INFO] [stderr]    |         ^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `super::List`
[INFO] [stderr]    --> src/second.rs:106:9
[INFO] [stderr]     |
[INFO] [stderr] 106 |     use super::List;
[INFO] [stderr]     |         ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `super::List`
[INFO] [stderr]    --> src/fourth.rs:147:6
[INFO] [stderr]     |
[INFO] [stderr] 147 |     use super::List;
[INFO] [stderr]     |         ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `super::List`
[INFO] [stderr]    --> src/fifth.rs:119:9
[INFO] [stderr]     |
[INFO] [stderr] 119 |     use super::List;
[INFO] [stderr]     |         ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `Node`
[INFO] [stderr]   --> src/fourth.rs:43:4
[INFO] [stderr]    |
[INFO] [stderr] 43 |             Node => {
[INFO] [stderr]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_Node`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: private type `second::IntoIter<T>` in public interface (error E0446)
[INFO] [stderr]   --> src/second.rs:54:5
[INFO] [stderr]    |
[INFO] [stderr] 54 | /     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stderr] 55 | |         IntoIter(self)
[INFO] [stderr] 56 | |     }
[INFO] [stderr]    | |_____^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(private_in_public)]` on by default
[INFO] [stderr]    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stderr]    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `More`
[INFO] [stderr]  --> src/first.rs:9:5
[INFO] [stderr]   |
[INFO] [stderr] 9 |     More(Box<Node>),
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `elem`
[INFO] [stderr]   --> src/first.rs:13:5
[INFO] [stderr]    |
[INFO] [stderr] 13 |     elem: i32,
[INFO] [stderr]    |     ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/first.rs:18:5
[INFO] [stderr]    |
[INFO] [stderr] 18 |     pub fn new() -> List {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `push`
[INFO] [stderr]   --> src/first.rs:22:5
[INFO] [stderr]    |
[INFO] [stderr] 22 |     pub fn push(&mut self, value: i32) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `pop`
[INFO] [stderr]   --> src/first.rs:29:5
[INFO] [stderr]    |
[INFO] [stderr] 29 |     pub fn pop(&mut self) -> Option<i32> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/second.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn new() -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `push`
[INFO] [stderr]   --> src/second.rs:28:5
[INFO] [stderr]    |
[INFO] [stderr] 28 |     pub fn push(&mut self, value: T) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek`
[INFO] [stderr]   --> src/second.rs:42:5
[INFO] [stderr]    |
[INFO] [stderr] 42 |     pub fn peek(&self) -> Option<&T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek_mut`
[INFO] [stderr]   --> src/second.rs:48:5
[INFO] [stderr]    |
[INFO] [stderr] 48 |     pub fn peek_mut(&mut self) -> Option<&mut T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `into_iter`
[INFO] [stderr]   --> src/second.rs:54:5
[INFO] [stderr]    |
[INFO] [stderr] 54 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `iter`
[INFO] [stderr]   --> src/second.rs:58:5
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `iter_mut`
[INFO] [stderr]   --> src/second.rs:62:5
[INFO] [stderr]    |
[INFO] [stderr] 62 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/third.rs:20:2
[INFO] [stderr]    |
[INFO] [stderr] 20 |     pub fn new() -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `append`
[INFO] [stderr]   --> src/third.rs:24:2
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn append(&self, elem: T) -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `tail`
[INFO] [stderr]   --> src/third.rs:31:2
[INFO] [stderr]    |
[INFO] [stderr] 31 |     pub fn tail(&self) -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `head`
[INFO] [stderr]   --> src/third.rs:35:2
[INFO] [stderr]    |
[INFO] [stderr] 35 |     pub fn head(&self) -> Option<&T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `iter`
[INFO] [stderr]   --> src/third.rs:39:2
[INFO] [stderr]    |
[INFO] [stderr] 39 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/fourth.rs:18:2
[INFO] [stderr]    |
[INFO] [stderr] 18 |     fn new(elem: T) -> Rc<RefCell<Self>> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/fourth.rs:30:2
[INFO] [stderr]    |
[INFO] [stderr] 30 |     pub fn new() -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `push_front`
[INFO] [stderr]   --> src/fourth.rs:34:2
[INFO] [stderr]    |
[INFO] [stderr] 34 |     pub fn push_front(&mut self, elem: T) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `push_back`
[INFO] [stderr]   --> src/fourth.rs:50:2
[INFO] [stderr]    |
[INFO] [stderr] 50 |     pub fn push_back(&mut self, elem: T) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek_front`
[INFO] [stderr]   --> src/fourth.rs:96:2
[INFO] [stderr]    |
[INFO] [stderr] 96 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek_back`
[INFO] [stderr]    --> src/fourth.rs:102:2
[INFO] [stderr]     |
[INFO] [stderr] 102 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek_front_mut`
[INFO] [stderr]    --> src/fourth.rs:108:2
[INFO] [stderr]     |
[INFO] [stderr] 108 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek_back_mut`
[INFO] [stderr]    --> src/fourth.rs:114:2
[INFO] [stderr]     |
[INFO] [stderr] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `into_iter`
[INFO] [stderr]    --> src/fourth.rs:120:2
[INFO] [stderr]     |
[INFO] [stderr] 120 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/fifth.rs:26:5
[INFO] [stderr]    |
[INFO] [stderr] 26 |     pub fn new() -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `push`
[INFO] [stderr]   --> src/fifth.rs:30:5
[INFO] [stderr]    |
[INFO] [stderr] 30 |     pub fn push(&mut self, elem: T) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek`
[INFO] [stderr]   --> src/fifth.rs:61:5
[INFO] [stderr]    |
[INFO] [stderr] 61 |     pub fn peek(&self) -> Option<&T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek_mut`
[INFO] [stderr]   --> src/fifth.rs:65:5
[INFO] [stderr]    |
[INFO] [stderr] 65 |     pub fn peek_mut(&mut self) -> Option<&mut T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `into_iter`
[INFO] [stderr]   --> src/fifth.rs:69:5
[INFO] [stderr]    |
[INFO] [stderr] 69 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `iter`
[INFO] [stderr]   --> src/fifth.rs:73:5
[INFO] [stderr]    |
[INFO] [stderr] 73 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `iter_mut`
[INFO] [stderr]   --> src/fifth.rs:77:5
[INFO] [stderr]    |
[INFO] [stderr] 77 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variable `Node` should have a snake case name
[INFO] [stderr]   --> src/fourth.rs:43:4
[INFO] [stderr]    |
[INFO] [stderr] 43 |             Node => {
[INFO] [stderr]    |             ^^^^ help: convert the identifier to snake case: `node`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 40 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `Node`
[INFO] [stderr]   --> src/fourth.rs:43:4
[INFO] [stderr]    |
[INFO] [stderr] 43 |             Node => {
[INFO] [stderr]    |             ^^^^ help: if this is intentional, prefix it with an underscore: `_Node`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: private type `second::IntoIter<T>` in public interface (error E0446)
[INFO] [stderr]   --> src/second.rs:54:5
[INFO] [stderr]    |
[INFO] [stderr] 54 | /     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stderr] 55 | |         IntoIter(self)
[INFO] [stderr] 56 | |     }
[INFO] [stderr]    | |_____^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(private_in_public)]` on by default
[INFO] [stderr]    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stderr]    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek`
[INFO] [stderr]   --> src/fifth.rs:61:5
[INFO] [stderr]    |
[INFO] [stderr] 61 |     pub fn peek(&self) -> Option<&T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `peek_mut`
[INFO] [stderr]   --> src/fifth.rs:65:5
[INFO] [stderr]    |
[INFO] [stderr] 65 |     pub fn peek_mut(&mut self) -> Option<&mut T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: variable `Node` should have a snake case name
[INFO] [stderr]   --> src/fourth.rs:43:4
[INFO] [stderr]    |
[INFO] [stderr] 43 |             Node => {
[INFO] [stderr]    |             ^^^^ help: convert the identifier to snake case: `node`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 5 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.72s
[INFO] running `"docker" "inspect" "d0050d27a61e3fe1d4071b309c26badecf34681d68f33318528edd57731e0dc2"`
[INFO] running `"docker" "rm" "-f" "d0050d27a61e3fe1d4071b309c26badecf34681d68f33318528edd57731e0dc2"`
[INFO] [stdout] d0050d27a61e3fe1d4071b309c26badecf34681d68f33318528edd57731e0dc2