[INFO] cloning repository https://github.com/daniel-j-anderson-dev/linked_lists_book
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/daniel-j-anderson-dev/linked_lists_book" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdaniel-j-anderson-dev%2Flinked_lists_book", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdaniel-j-anderson-dev%2Flinked_lists_book'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] df5e3098d35a90a0fabe5039f84ae0bb0c5de713
[INFO] checking daniel-j-anderson-dev/linked_lists_book against try#5ef65a4ed75279dc1b7a26cedc27293a9f4ca8db for pr-143717
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdaniel-j-anderson-dev%2Flinked_lists_book" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/daniel-j-anderson-dev/linked_lists_book
[INFO] finished tweaking git repo https://github.com/daniel-j-anderson-dev/linked_lists_book
[INFO] tweaked toml for git repo https://github.com/daniel-j-anderson-dev/linked_lists_book written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/daniel-j-anderson-dev/linked_lists_book on toolchain 5ef65a4ed75279dc1b7a26cedc27293a9f4ca8db
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+5ef65a4ed75279dc1b7a26cedc27293a9f4ca8db" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/daniel-j-anderson-dev/linked_lists_book 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" "+5ef65a4ed75279dc1b7a26cedc27293a9f4ca8db" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+5ef65a4ed75279dc1b7a26cedc27293a9f4ca8db" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 24555272dd63ab6bd37cd90d5a480824c1e79e0e3674f871e50f50d9b5b49717
[INFO] running `Command { std: "docker" "start" "-a" "24555272dd63ab6bd37cd90d5a480824c1e79e0e3674f871e50f50d9b5b49717", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "24555272dd63ab6bd37cd90d5a480824c1e79e0e3674f871e50f50d9b5b49717", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "24555272dd63ab6bd37cd90d5a480824c1e79e0e3674f871e50f50d9b5b49717", kill_on_drop: false }`
[INFO] [stdout] 24555272dd63ab6bd37cd90d5a480824c1e79e0e3674f871e50f50d9b5b49717
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+5ef65a4ed75279dc1b7a26cedc27293a9f4ca8db" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4301fa4de323c0fadfdd4299de8761ab34aed6c5dd745c07873572fd75a4332f
[INFO] running `Command { std: "docker" "start" "-a" "4301fa4de323c0fadfdd4299de8761ab34aed6c5dd745c07873572fd75a4332f", kill_on_drop: false }`
[INFO] [stderr]     Checking linked_lists_book v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: struct `List` is never constructed
[INFO] [stdout]  --> src/first.rs:3:12
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub struct List<E> {
[INFO] [stdout]   |            ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Link` is never used
[INFO] [stdout]  --> src/first.rs:7:6
[INFO] [stdout]   |
[INFO] [stdout] 7 | enum Link<E> {
[INFO] [stdout]   |      ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Node` is never constructed
[INFO] [stdout]   --> src/first.rs:12:8
[INFO] [stdout]    |
[INFO] [stdout] 12 | struct Node<E> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `push`, and `pop` are never used
[INFO] [stdout]   --> src/first.rs:18:18
[INFO] [stdout]    |
[INFO] [stdout] 17 | impl<E> List<E> {
[INFO] [stdout]    | --------------- associated items in this implementation
[INFO] [stdout] 18 |     pub const fn new() -> Self {
[INFO] [stdout]    |                  ^^^
[INFO] [stdout] ...
[INFO] [stdout] 22 |     pub fn push(&mut self, element: E) {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 36 |     pub fn pop(&mut self) -> Option<E> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `push`, `peek`, and `peek_mut` are never used
[INFO] [stdout]   --> src/second.rs:15:18
[INFO] [stdout]    |
[INFO] [stdout] 14 | impl<E> List<E> {
[INFO] [stdout]    | --------------- associated items in this implementation
[INFO] [stdout] 15 |     pub const fn new() -> Self {
[INFO] [stdout]    |                  ^^^
[INFO] [stdout] ...
[INFO] [stdout] 19 |     pub fn push(&mut self, element: E) {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 33 |     pub fn peek(&self) -> Option<&E> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 36 |     pub fn peek_mut(&mut self) -> Option<&mut E> {
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `iter` and `iter_mut` are never used
[INFO] [stdout]   --> src/second/iter.rs:12:12
[INFO] [stdout]    |
[INFO] [stdout] 11 | impl<E> List<E> {
[INFO] [stdout]    | --------------- methods in this implementation
[INFO] [stdout] 12 |     pub fn iter(&self) -> ReferenceIterator<'_, E> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 15 |     pub fn iter_mut(&mut self) -> MutableReferenceIterator<E> {
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `ReferenceIterator` is never constructed
[INFO] [stdout]   --> src/second/iter.rs:28:12
[INFO] [stdout]    |
[INFO] [stdout] 28 | pub struct ReferenceIterator<'a, E> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `MutableReferenceIterator` is never constructed
[INFO] [stdout]   --> src/second/iter.rs:43:12
[INFO] [stdout]    |
[INFO] [stdout] 43 | pub struct MutableReferenceIterator<'a, E> {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]   --> src/second/iter.rs:15:21
[INFO] [stdout]    |
[INFO] [stdout] 15 |     pub fn iter_mut(&mut self) -> MutableReferenceIterator<E> {
[INFO] [stdout]    |                     ^^^^^^^^^     --------------------------- the lifetime gets resolved as `'_`
[INFO] [stdout]    |                     |
[INFO] [stdout]    |                     this lifetime flows to the output
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]    |
[INFO] [stdout] 15 |     pub fn iter_mut(&mut self) -> MutableReferenceIterator<'_, E> {
[INFO] [stdout]    |                                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]   --> src/second/iter.rs:15:21
[INFO] [stdout]    |
[INFO] [stdout] 15 |     pub fn iter_mut(&mut self) -> MutableReferenceIterator<E> {
[INFO] [stdout]    |                     ^^^^^^^^^     --------------------------- the lifetime gets resolved as `'_`
[INFO] [stdout]    |                     |
[INFO] [stdout]    |                     this lifetime flows to the output
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]    |
[INFO] [stdout] 15 |     pub fn iter_mut(&mut self) -> MutableReferenceIterator<'_, E> {
[INFO] [stdout]    |                                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.11s
[INFO] running `Command { std: "docker" "inspect" "4301fa4de323c0fadfdd4299de8761ab34aed6c5dd745c07873572fd75a4332f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4301fa4de323c0fadfdd4299de8761ab34aed6c5dd745c07873572fd75a4332f", kill_on_drop: false }`
[INFO] [stdout] 4301fa4de323c0fadfdd4299de8761ab34aed6c5dd745c07873572fd75a4332f
