[INFO] cloning repository https://github.com/Maan-el/linked_lists
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Maan-el/linked_lists" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMaan-el%2Flinked_lists", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMaan-el%2Flinked_lists'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 15192ca3920c62b1a038f0cf6f114eb112f9aa55
[INFO] testing Maan-el/linked_lists against master#d98a5da813da67eb189387b8ccfb73cf481275d8+rustflags=-Copt-level=3 for pr-138759
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMaan-el%2Flinked_lists" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/Maan-el/linked_lists
[INFO] finished tweaking git repo https://github.com/Maan-el/linked_lists
[INFO] tweaked toml for git repo https://github.com/Maan-el/linked_lists written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/Maan-el/linked_lists on toolchain d98a5da813da67eb189387b8ccfb73cf481275d8
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d98a5da813da67eb189387b8ccfb73cf481275d8" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/Maan-el/linked_lists 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" "+d98a5da813da67eb189387b8ccfb73cf481275d8" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+d98a5da813da67eb189387b8ccfb73cf481275d8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6914cc874f7365835e16a467c4eb1f638d92599b36f18429801e1a909ed6b08d
[INFO] running `Command { std: "docker" "start" "-a" "6914cc874f7365835e16a467c4eb1f638d92599b36f18429801e1a909ed6b08d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6914cc874f7365835e16a467c4eb1f638d92599b36f18429801e1a909ed6b08d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6914cc874f7365835e16a467c4eb1f638d92599b36f18429801e1a909ed6b08d", kill_on_drop: false }`
[INFO] [stdout] 6914cc874f7365835e16a467c4eb1f638d92599b36f18429801e1a909ed6b08d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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 -Copt-level=3" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+d98a5da813da67eb189387b8ccfb73cf481275d8" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 48a823ef8bc3c5ae8dd276b5d40a9dbbd22c86b312a027733f84802947744cc6
[INFO] running `Command { std: "docker" "start" "-a" "48a823ef8bc3c5ae8dd276b5d40a9dbbd22c86b312a027733f84802947744cc6", kill_on_drop: false }`
[INFO] [stderr]    Compiling linked_lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]   --> src/fourth.rs:67:23
[INFO] [stdout]    |
[INFO] [stdout] 67 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[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] 67 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:103:22
[INFO] [stdout]     |
[INFO] [stdout] 103 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |                      ^^^^^            ------ the lifetime gets resolved as `'_`
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 103 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:109:26
[INFO] [stdout]     |
[INFO] [stdout] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                          ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:115:27
[INFO] [stdout]     |
[INFO] [stdout] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                           ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:186:17
[INFO] [stdout]     |
[INFO] [stdout] 186 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |                 ^^^^^     ------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 186 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]     |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:195:21
[INFO] [stdout]     |
[INFO] [stdout] 195 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                     ^^^^^^^^^     ---------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 195 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:204:23
[INFO] [stdout]     |
[INFO] [stdout] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stdout]     |                       ^^^^^^^^^     ------------ the lifetime gets resolved as `'_`
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stdout]     |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.39s
[INFO] running `Command { std: "docker" "inspect" "48a823ef8bc3c5ae8dd276b5d40a9dbbd22c86b312a027733f84802947744cc6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "48a823ef8bc3c5ae8dd276b5d40a9dbbd22c86b312a027733f84802947744cc6", kill_on_drop: false }`
[INFO] [stdout] 48a823ef8bc3c5ae8dd276b5d40a9dbbd22c86b312a027733f84802947744cc6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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 -Copt-level=3" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+d98a5da813da67eb189387b8ccfb73cf481275d8" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1933b30a93adf69788d88b205dd4eac1594ed0f998670c77763c991fb557cbf1
[INFO] running `Command { std: "docker" "start" "-a" "1933b30a93adf69788d88b205dd4eac1594ed0f998670c77763c991fb557cbf1", kill_on_drop: false }`
[INFO] [stderr]    Compiling linked_lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]   --> src/fourth.rs:67:23
[INFO] [stdout]    |
[INFO] [stdout] 67 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[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] 67 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:103:22
[INFO] [stdout]     |
[INFO] [stdout] 103 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |                      ^^^^^            ------ the lifetime gets resolved as `'_`
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 103 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:109:26
[INFO] [stdout]     |
[INFO] [stdout] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                          ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:115:27
[INFO] [stdout]     |
[INFO] [stdout] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                           ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:186:17
[INFO] [stdout]     |
[INFO] [stdout] 186 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |                 ^^^^^     ------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 186 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]     |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:195:21
[INFO] [stdout]     |
[INFO] [stdout] 195 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                     ^^^^^^^^^     ---------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 195 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:204:23
[INFO] [stdout]     |
[INFO] [stdout] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stdout]     |                       ^^^^^^^^^     ------------ the lifetime gets resolved as `'_`
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stdout]     |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]   --> src/fourth.rs:67:23
[INFO] [stdout]    |
[INFO] [stdout] 67 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[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] 67 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:103:22
[INFO] [stdout]     |
[INFO] [stdout] 103 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |                      ^^^^^            ------ the lifetime gets resolved as `'_`
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 103 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:109:26
[INFO] [stdout]     |
[INFO] [stdout] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                          ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/fourth.rs:115:27
[INFO] [stdout]     |
[INFO] [stdout] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                           ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:186:17
[INFO] [stdout]     |
[INFO] [stdout] 186 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |                 ^^^^^     ------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 186 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]     |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:195:21
[INFO] [stdout]     |
[INFO] [stdout] 195 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                     ^^^^^^^^^     ---------- the lifetime gets resolved as `'_`
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 195 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stdout]    --> src/sixth.rs:204:23
[INFO] [stdout]     |
[INFO] [stdout] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stdout]     |                       ^^^^^^^^^     ------------ the lifetime gets resolved as `'_`
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       this lifetime flows to the output
[INFO] [stdout]     |
[INFO] [stdout] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stdout]     |
[INFO] [stdout] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stdout]     |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 2.38s
[INFO] running `Command { std: "docker" "inspect" "1933b30a93adf69788d88b205dd4eac1594ed0f998670c77763c991fb557cbf1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1933b30a93adf69788d88b205dd4eac1594ed0f998670c77763c991fb557cbf1", kill_on_drop: false }`
[INFO] [stdout] 1933b30a93adf69788d88b205dd4eac1594ed0f998670c77763c991fb557cbf1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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 -Copt-level=3" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+d98a5da813da67eb189387b8ccfb73cf481275d8" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 3837ba0cfcd52b5a57c3635d3b349887d291802dc49a9bfce37d2893fe4cea1d
[INFO] running `Command { std: "docker" "start" "-a" "3837ba0cfcd52b5a57c3635d3b349887d291802dc49a9bfce37d2893fe4cea1d", kill_on_drop: false }`
[INFO] [stderr] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stderr]   --> src/fourth.rs:67:23
[INFO] [stderr]    |
[INFO] [stderr] 67 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stderr]    |                       ^^^^^            ------ the lifetime gets resolved as `'_`
[INFO] [stderr]    |                       |
[INFO] [stderr]    |                       this lifetime flows to the output
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stderr] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stderr]    |
[INFO] [stderr] 67 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stderr]    |                                            +++
[INFO] [stderr] 
[INFO] [stderr] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stderr]    --> src/fourth.rs:103:22
[INFO] [stderr]     |
[INFO] [stderr] 103 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stderr]     |                      ^^^^^            ------ the lifetime gets resolved as `'_`
[INFO] [stderr]     |                      |
[INFO] [stderr]     |                      this lifetime flows to the output
[INFO] [stderr]     |
[INFO] [stderr] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stderr]     |
[INFO] [stderr] 103 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stderr]     |                                           +++
[INFO] [stderr] 
[INFO] [stderr] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stderr]    --> src/fourth.rs:109:26
[INFO] [stderr]     |
[INFO] [stderr] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |                          ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stderr]     |                          |
[INFO] [stderr]     |                          this lifetime flows to the output
[INFO] [stderr]     |
[INFO] [stderr] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stderr]     |
[INFO] [stderr] 109 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stderr]     |                                                      +++
[INFO] [stderr] 
[INFO] [stderr] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stderr]    --> src/fourth.rs:115:27
[INFO] [stderr]     |
[INFO] [stderr] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |                           ^^^^^^^^^            --------- the lifetime gets resolved as `'_`
[INFO] [stderr]     |                           |
[INFO] [stderr]     |                           this lifetime flows to the output
[INFO] [stderr]     |
[INFO] [stderr] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stderr]     |
[INFO] [stderr] 115 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stderr]     |                                                       +++
[INFO] [stderr] 
[INFO] [stderr] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stderr]    --> src/sixth.rs:186:17
[INFO] [stderr]     |
[INFO] [stderr] 186 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stderr]     |                 ^^^^^     ------- the lifetime gets resolved as `'_`
[INFO] [stderr]     |                 |
[INFO] [stderr]     |                 this lifetime flows to the output
[INFO] [stderr]     |
[INFO] [stderr] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stderr]     |
[INFO] [stderr] 186 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stderr]     |                                +++
[INFO] [stderr] 
[INFO] [stderr] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stderr]    --> src/sixth.rs:195:21
[INFO] [stderr]     |
[INFO] [stderr] 195 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stderr]     |                     ^^^^^^^^^     ---------- the lifetime gets resolved as `'_`
[INFO] [stderr]     |                     |
[INFO] [stderr]     |                     this lifetime flows to the output
[INFO] [stderr]     |
[INFO] [stderr] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stderr]     |
[INFO] [stderr] 195 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stderr]     |                                           +++
[INFO] [stderr] 
[INFO] [stderr] warning: lifetime flowing from input to output with different syntax can be confusing
[INFO] [stderr]    --> src/sixth.rs:204:23
[INFO] [stderr]     |
[INFO] [stderr] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stderr]     |                       ^^^^^^^^^     ------------ the lifetime gets resolved as `'_`
[INFO] [stderr]     |                       |
[INFO] [stderr]     |                       this lifetime flows to the output
[INFO] [stderr]     |
[INFO] [stderr] help: one option is to remove the lifetime for references and use the anonymous lifetime for paths
[INFO] [stderr]     |
[INFO] [stderr] 204 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stderr]     |                                               +++
[INFO] [stderr] 
[INFO] [stderr] warning: `linked_lists` (lib) generated 7 warnings
[INFO] [stderr] warning: `linked_lists` (lib test) generated 7 warnings (7 duplicates)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.05s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/linked_lists-9a430d1158cd0508)
[INFO] [stdout] 
[INFO] [stdout] running 31 tests
[INFO] [stdout] test fifth::test::basics ... ok
[INFO] [stdout] test fifth::test::iter_mut ... ok
[INFO] [stdout] test second::test::iter_mut ... ok
[INFO] [stdout] test second::test::peek ... ok
[INFO] [stdout] test sixth::test::test_basic ... ok
[INFO] [stdout] test sixth::test::test_basic_front ... ok
[INFO] [stdout] test sixth::test::test_cursor_move_peek ... ok
[INFO] [stdout] test sixth::test::test_cursor_mut_insert ... ok
[INFO] [stdout] test sixth::test::test_debug ... ok
[INFO] [stdout] test fifth::test::into_iter ... ok
[INFO] [stdout] test sixth::test::test_iterator ... ok
[INFO] [stdout] test fifth::test::iter ... ok
[INFO] [stdout] test sixth::test::test_iterator_double_end ... ok
[INFO] [stdout] test fourth::test::basics ... ok
[INFO] [stdout] test first::test::basico ... ok
[INFO] [stdout] test sixth::test::test_eq ... ok
[INFO] [stdout] test fourth::test::into_iter ... ok
[INFO] [stdout] test second::test::iter ... ok
[INFO] [stdout] test sixth::test::test_iterator_mut_double_end ... ok
[INFO] [stdout] test sixth::test::test_hashmap ... ok
[INFO] [stdout] test sixth::test::test_mut_iter ... ok
[INFO] [stdout] test sixth::test::test_ord ... ok
[INFO] [stdout] test tests::it_works ... ok
[INFO] [stdout] test third::test::basics ... ok
[INFO] [stdout] test third::test::iter ... ok
[INFO] [stdout] test sixth::test::test_ord_nan ... ok
[INFO] [stdout] test sixth::test::test_rev_iter ... ok
[INFO] [stdout] test fifth::test::miri_food ... ok
[INFO] [stdout] test second::test::basico ... ok
[INFO] [stdout] test fourth::test::peek ... ok
[INFO] [stdout] test second::test::into_iter ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 31 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.01s
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests linked_lists
[INFO] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test src/sixth.rs - sixth::assert_properties::iter_mut_invariant (line 791) - compile fail ... FAILED
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/sixth.rs - sixth::assert_properties::iter_mut_invariant (line 791) stdout ----
[INFO] [stdout] error[E0432]: unresolved import `linked_list`
[INFO] [stdout]  --> src/sixth.rs:792:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use linked_list::IterMut;
[INFO] [stdout]   |     ^^^^^^^^^^^ use of unresolved module or unlinked crate `linked_list`
[INFO] [stdout]   |
[INFO] [stdout] help: there is a crate or module with a similar name
[INFO] [stdout]   |
[INFO] [stdout] 3 | use linked_lists::IterMut;
[INFO] [stdout]   |                +
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 previous error
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0432`.
[INFO] [stdout] Some expected error codes were not found: ["E0308"]
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout]     src/sixth.rs - sixth::assert_properties::iter_mut_invariant (line 791)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.08s
[INFO] [stdout] 
[INFO] [stderr] error: doctest failed, to rerun pass `--doc`
[INFO] running `Command { std: "docker" "inspect" "3837ba0cfcd52b5a57c3635d3b349887d291802dc49a9bfce37d2893fe4cea1d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3837ba0cfcd52b5a57c3635d3b349887d291802dc49a9bfce37d2893fe4cea1d", kill_on_drop: false }`
[INFO] [stdout] 3837ba0cfcd52b5a57c3635d3b349887d291802dc49a9bfce37d2893fe4cea1d
