[INFO] updating cached repository https://github.com/Pungyeon/rusty-lists
[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] 7e84440d222e7b6bdb69f05555b9ff4c1f21a9d8
[INFO] checking Pungyeon/rusty-lists against try#1a608893c03d7722effeb0058e82770bd36b4b3c for pr-66504-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FPungyeon%2Frusty-lists" "/workspace/builds/worker-11/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Pungyeon/rusty-lists on toolchain 1a608893c03d7722effeb0058e82770bd36b4b3c
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1a608893c03d7722effeb0058e82770bd36b4b3c" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/Pungyeon/rusty-lists
[INFO] finished tweaking git repo https://github.com/Pungyeon/rusty-lists
[INFO] tweaked toml for git repo https://github.com/Pungyeon/rusty-lists written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate git repo https://github.com/Pungyeon/rusty-lists already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1a608893c03d7722effeb0058e82770bd36b4b3c" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "+1a608893c03d7722effeb0058e82770bd36b4b3c" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 6a6ff4fda43202554ccad77ca74ebbd104af05fad65b26ef4186c0352d787a27
[INFO] running `"docker" "start" "-a" "6a6ff4fda43202554ccad77ca74ebbd104af05fad65b26ef4186c0352d787a27"`
[INFO] [stderr]     Checking rusty-cart v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused import: `super::Stack`
[INFO] [stderr]   --> src/lists/stack.rs:99:9
[INFO] [stderr]    |
[INFO] [stderr] 99 |     use super::Stack;
[INFO] [stderr]    |         ^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `super::BinaryTree`
[INFO] [stderr]   --> src/lists/binary.rs:81:9
[INFO] [stderr]    |
[INFO] [stderr] 81 |     use super::BinaryTree;
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `elem`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:33:24
[INFO] [stderr]    |
[INFO] [stderr] 33 |     pub fn tail(&self, elem: T) -> List<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] warning: method is never used: `tail`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:33:5
[INFO] [stderr]    |
[INFO] [stderr] 33 |     pub fn tail(&self, elem: T) -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `head`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:41:5
[INFO] [stderr]    |
[INFO] [stderr] 41 |     pub fn head(&self) -> Option<&T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `test_tail`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:73:8
[INFO] [stderr]    |
[INFO] [stderr] 73 |     fn test_tail() {
[INFO] [stderr]    |        ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `elem`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:33:24
[INFO] [stderr]    |
[INFO] [stderr] 33 |     pub fn tail(&self, elem: T) -> List<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] warning: method is never used: `peek`
[INFO] [stderr]   --> src/lists/stack.rs:27:5
[INFO] [stderr]    |
[INFO] [stderr] 27 |     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: `iter`
[INFO] [stderr]   --> src/lists/stack.rs:37:5
[INFO] [stderr]    |
[INFO] [stderr] 37 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `iter_mut`
[INFO] [stderr]   --> src/lists/stack.rs:41:5
[INFO] [stderr]    |
[INFO] [stderr] 41 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `count`
[INFO] [stderr]   --> src/lists/binary.rs:16:5
[INFO] [stderr]    |
[INFO] [stderr] 16 |     pub fn count(self) -> usize {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `count`
[INFO] [stderr]   --> src/lists/binary.rs:49:5
[INFO] [stderr]    |
[INFO] [stderr] 49 |     pub fn count(self) -> usize {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `List`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:17:12
[INFO] [stderr]    |
[INFO] [stderr] 17 | pub struct List<T> {
[INFO] [stderr]    |            ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `new`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:22:5
[INFO] [stderr]    |
[INFO] [stderr] 22 |     pub fn new() -> Self {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `append`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:26:5
[INFO] [stderr]    |
[INFO] [stderr] 26 |     pub fn append(&self, elem: T) -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `tail`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:33:5
[INFO] [stderr]    |
[INFO] [stderr] 33 |     pub fn tail(&self, elem: T) -> List<T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `head`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:41:5
[INFO] [stderr]    |
[INFO] [stderr] 41 |     pub fn head(&self) -> Option<&T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `iter`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:45:5
[INFO] [stderr]    |
[INFO] [stderr] 45 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `test_tail`
[INFO] [stderr]   --> src/lists/persistently_linked.rs:73:8
[INFO] [stderr]    |
[INFO] [stderr] 73 |     fn test_tail() {
[INFO] [stderr]    |        ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.24s
[INFO] running `"docker" "inspect" "6a6ff4fda43202554ccad77ca74ebbd104af05fad65b26ef4186c0352d787a27"`
[INFO] running `"docker" "rm" "-f" "6a6ff4fda43202554ccad77ca74ebbd104af05fad65b26ef4186c0352d787a27"`
[INFO] [stdout] 6a6ff4fda43202554ccad77ca74ebbd104af05fad65b26ef4186c0352d787a27