[INFO] cloning repository https://github.com/Ember1100/lists
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Ember1100/lists" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEmber1100%2Flists", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEmber1100%2Flists'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] a14019a9471c4f1e62f9819a91639ce6f1b636ad
[INFO] testing Ember1100/lists against master#ec6f9a5b4413f74386267ef8efc93712c2ce6db6 for pr-155739
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEmber1100%2Flists" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/Ember1100/lists
[INFO] finished tweaking git repo https://github.com/Ember1100/lists
[INFO] tweaked toml for git repo https://github.com/Ember1100/lists written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/Ember1100/lists on toolchain ec6f9a5b4413f74386267ef8efc93712c2ce6db6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ec6f9a5b4413f74386267ef8efc93712c2ce6db6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/Ember1100/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" "+ec6f9a5b4413f74386267ef8efc93712c2ce6db6" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+ec6f9a5b4413f74386267ef8efc93712c2ce6db6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3a1fb56bdd7e14f68e7279f1d5c7c38c2c114e41a6601242304760292889266b
[INFO] running `Command { std: "docker" "start" "-a" "3a1fb56bdd7e14f68e7279f1d5c7c38c2c114e41a6601242304760292889266b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3a1fb56bdd7e14f68e7279f1d5c7c38c2c114e41a6601242304760292889266b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3a1fb56bdd7e14f68e7279f1d5c7c38c2c114e41a6601242304760292889266b", kill_on_drop: false }`
[INFO] [stdout] 3a1fb56bdd7e14f68e7279f1d5c7c38c2c114e41a6601242304760292889266b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+ec6f9a5b4413f74386267ef8efc93712c2ce6db6" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 315ccf48be0120e9f698ba98444019fff27afc5df4c21090e87995fa5a70aac8
[INFO] running `Command { std: "docker" "start" "-a" "315ccf48be0120e9f698ba98444019fff27afc5df4c21090e87995fa5a70aac8", kill_on_drop: false }`
[INFO] [stderr]    Compiling lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/fourth.rs:71:23
[INFO] [stdout]    |
[INFO] [stdout] 71 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |                       ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |                       |
[INFO] [stdout]    |                       the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 71 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:108:22
[INFO] [stdout]     |
[INFO] [stdout] 108 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |                      ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 108 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:114:26
[INFO] [stdout]     |
[INFO] [stdout] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                          ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:120:27
[INFO] [stdout]     |
[INFO] [stdout] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                           ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:162:17
[INFO] [stdout]     |
[INFO] [stdout] 162 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |                 ^^^^^     ^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 162 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]     |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:171:21
[INFO] [stdout]     |
[INFO] [stdout] 171 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                     ^^^^^^^^^     ^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 171 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:180:23
[INFO] [stdout]     |
[INFO] [stdout] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stdout]     |                       ^^^^^^^^^     ^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stdout]     |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.27s
[INFO] running `Command { std: "docker" "inspect" "315ccf48be0120e9f698ba98444019fff27afc5df4c21090e87995fa5a70aac8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "315ccf48be0120e9f698ba98444019fff27afc5df4c21090e87995fa5a70aac8", kill_on_drop: false }`
[INFO] [stdout] 315ccf48be0120e9f698ba98444019fff27afc5df4c21090e87995fa5a70aac8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+ec6f9a5b4413f74386267ef8efc93712c2ce6db6" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ef35f485ff3acd446c9dd1b53bb654451dde0d4ad92fb99d4cb412d83af6ad11
[INFO] running `Command { std: "docker" "start" "-a" "ef35f485ff3acd446c9dd1b53bb654451dde0d4ad92fb99d4cb412d83af6ad11", kill_on_drop: false }`
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/fourth.rs:71:23
[INFO] [stdout]    |
[INFO] [stdout] 71 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |                       ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |                       |
[INFO] [stdout]    |                       the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 71 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:108:22
[INFO] [stdout]     |
[INFO] [stdout] 108 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |                      ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 108 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:114:26
[INFO] [stdout]     |
[INFO] [stdout] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                          ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:120:27
[INFO] [stdout]     |
[INFO] [stdout] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                           ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:162:17
[INFO] [stdout]     |
[INFO] [stdout] 162 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |                 ^^^^^     ^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 162 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]     |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:171:21
[INFO] [stdout]     |
[INFO] [stdout] 171 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                     ^^^^^^^^^     ^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 171 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:180:23
[INFO] [stdout]     |
[INFO] [stdout] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stdout]     |                       ^^^^^^^^^     ^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stdout]     |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/fourth.rs:71:23
[INFO] [stdout]    |
[INFO] [stdout] 71 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]    |                       ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stdout]    |                       |
[INFO] [stdout]    |                       the lifetime is elided here
[INFO] [stdout]    |
[INFO] [stdout]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]    |
[INFO] [stdout] 71 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:108:22
[INFO] [stdout]     |
[INFO] [stdout] 108 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |                      ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 108 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:114:26
[INFO] [stdout]     |
[INFO] [stdout] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                          ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/fourth.rs:120:27
[INFO] [stdout]     |
[INFO] [stdout] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stdout]     |                           ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                           |
[INFO] [stdout]     |                           the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:162:17
[INFO] [stdout]     |
[INFO] [stdout] 162 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |                 ^^^^^     ^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                 |
[INFO] [stdout]     |                 the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 162 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stdout]     |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:171:21
[INFO] [stdout]     |
[INFO] [stdout] 171 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stdout]     |                     ^^^^^^^^^     ^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 171 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/linked_list.rs:180:23
[INFO] [stdout]     |
[INFO] [stdout] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stdout]     |                       ^^^^^^^^^     ^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                       |
[INFO] [stdout]     |                       the lifetime is elided here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stdout]     |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 1.00s
[INFO] running `Command { std: "docker" "inspect" "ef35f485ff3acd446c9dd1b53bb654451dde0d4ad92fb99d4cb412d83af6ad11", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ef35f485ff3acd446c9dd1b53bb654451dde0d4ad92fb99d4cb412d83af6ad11", kill_on_drop: false }`
[INFO] [stdout] ef35f485ff3acd446c9dd1b53bb654451dde0d4ad92fb99d4cb412d83af6ad11
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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" "-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+ec6f9a5b4413f74386267ef8efc93712c2ce6db6" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 406844c15b833d57a29a063c93adfd5538285cda84f3e4e8dc037b3d6731a0b9
[INFO] running `Command { std: "docker" "start" "-a" "406844c15b833d57a29a063c93adfd5538285cda84f3e4e8dc037b3d6731a0b9", kill_on_drop: false }`
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]   --> src/fourth.rs:71:23
[INFO] [stderr]    |
[INFO] [stderr] 71 |     pub fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stderr]    |                       ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stderr]    |                       |
[INFO] [stderr]    |                       the lifetime is elided here
[INFO] [stderr]    |
[INFO] [stderr]    = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr]    = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]    |
[INFO] [stderr] 71 |     pub fn peek_front(&self) -> Option<Ref<'_, T>> {
[INFO] [stderr]    |                                            +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/fourth.rs:108:22
[INFO] [stderr]     |
[INFO] [stderr] 108 |     pub fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stderr]     |                      ^^^^^            ^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                      |
[INFO] [stderr]     |                      the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 108 |     pub fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stderr]     |                                           +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/fourth.rs:114:26
[INFO] [stderr]     |
[INFO] [stderr] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |                          ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                          |
[INFO] [stderr]     |                          the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 114 |     pub fn peek_back_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stderr]     |                                                      +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/fourth.rs:120:27
[INFO] [stderr]     |
[INFO] [stderr] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<T>> {
[INFO] [stderr]     |                           ^^^^^^^^^            ^^^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                           |
[INFO] [stderr]     |                           the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 120 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stderr]     |                                                       +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/linked_list.rs:162:17
[INFO] [stderr]     |
[INFO] [stderr] 162 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stderr]     |                 ^^^^^     ^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                 |
[INFO] [stderr]     |                 the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 162 |     pub fn iter(&self) -> Iter<'_, T> {
[INFO] [stderr]     |                                +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/linked_list.rs:171:21
[INFO] [stderr]     |
[INFO] [stderr] 171 |     pub fn iter_mut(&mut self) -> IterMut<T> {
[INFO] [stderr]     |                     ^^^^^^^^^     ^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                     |
[INFO] [stderr]     |                     the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 171 |     pub fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stderr]     |                                           +++
[INFO] [stderr] 
[INFO] [stderr] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stderr]    --> src/linked_list.rs:180:23
[INFO] [stderr]     |
[INFO] [stderr] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<T> {
[INFO] [stderr]     |                       ^^^^^^^^^     ^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stderr]     |                       |
[INFO] [stderr]     |                       the lifetime is elided here
[INFO] [stderr]     |
[INFO] [stderr]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stderr] help: use `'_` for type paths
[INFO] [stderr]     |
[INFO] [stderr] 180 |     pub fn cursor_mut(&mut self) -> CursorMut<'_, T> {
[INFO] [stderr]     |                                               +++
[INFO] [stderr] 
[INFO] [stderr] warning: `lists` (lib) generated 7 warnings (run `cargo fix --lib -p lists` to apply 7 suggestions)
[INFO] [stderr] warning: `lists` (lib test) generated 7 warnings (7 duplicates)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/lists-d74ae4756691c45b)
[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 fifth::test::iter ... ok
[INFO] [stdout] test fifth::test::miri_food ... ok
[INFO] [stdout] test fifth::test::into_iter ... ok
[INFO] [stdout] test linked_list::test::test_basic_front ... ok
[INFO] [stdout] test linked_list::test::test_basic ... ok
[INFO] [stdout] test linked_list::test::test_cursor_move_peek ... ok
[INFO] [stdout] test linked_list::test::test_cursor_mut_insert ... ok
[INFO] [stdout] test linked_list::test::test_debug ... ok
[INFO] [stdout] test linked_list::test::test_eq ... ok
[INFO] [stdout] test linked_list::test::test_hashmap ... ok
[INFO] [stdout] test linked_list::test::test_iterator_mut_double_end ... ok
[INFO] [stdout] test linked_list::test::test_mut_iter ... ok
[INFO] [stdout] test linked_list::test::test_iterator ... ok
[INFO] [stdout] test linked_list::test::test_iterator_double_end ... ok
[INFO] [stdout] test linked_list::test::test_ord ... ok
[INFO] [stdout] test linked_list::test::test_ord_nan ... ok
[INFO] [stdout] test linked_list::test::test_rev_iter ... ok
[INFO] [stdout] test tests::basics ... ok
[INFO] [stdout] test tests::basics2 ... ok
[INFO] [stdout] test tests::fourth ... ok
[INFO] [stdout] test tests::basics_third ... ok
[INFO] [stdout] test tests::fourth_peek ... ok
[INFO] [stdout] test tests::basics3 ... ok
[INFO] [stdout] test tests::fourth_into_iter ... ok
[INFO] [stdout] test tests::iter ... ok
[INFO] [stdout] test tests::iter_mut ... ok
[INFO] [stdout] test tests::it_works ... ok
[INFO] [stdout] test tests::into_iter ... ok
[INFO] [stdout] test tests::iter_third ... ok
[INFO] [stderr]    Doc-tests lists
[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] [stdout] 
[INFO] [stdout] running 1 test
[INFO] [stdout] test src/linked_list.rs - linked_list::assert_properties::iter_mut_invariant (line 742) - compile fail ... FAILED
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/linked_list.rs - linked_list::assert_properties::iter_mut_invariant (line 742) stdout ----
[INFO] [stdout] error[E0432]: unresolved import `linked_list`
[INFO] [stdout]    --> src/linked_list.rs:743:5
[INFO] [stdout]     |
[INFO] [stdout] 743 | use linked_list::IterMut;
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout] help: a similar path exists
[INFO] [stdout]     |
[INFO] [stdout] 743 | use lists::linked_list::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/linked_list.rs - linked_list::assert_properties::iter_mut_invariant (line 742)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.07s
[INFO] [stdout] 
[INFO] [stderr] error: doctest failed, to rerun pass `--doc`
[INFO] running `Command { std: "docker" "inspect" "406844c15b833d57a29a063c93adfd5538285cda84f3e4e8dc037b3d6731a0b9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "406844c15b833d57a29a063c93adfd5538285cda84f3e4e8dc037b3d6731a0b9", kill_on_drop: false }`
[INFO] [stdout] 406844c15b833d57a29a063c93adfd5538285cda84f3e4e8dc037b3d6731a0b9
