[INFO] cloning repository https://github.com/jo3yzhu/too-many-lists
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/jo3yzhu/too-many-lists" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjo3yzhu%2Ftoo-many-lists", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjo3yzhu%2Ftoo-many-lists'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 992da1900da48b7849342f549b7c163579c6b3c8
[INFO] checking jo3yzhu/too-many-lists against master#507271bc119683008ec719ecee48814e8ac86c65 for pr-146440
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjo3yzhu%2Ftoo-many-lists" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/jo3yzhu/too-many-lists
[INFO] finished tweaking git repo https://github.com/jo3yzhu/too-many-lists
[INFO] tweaked toml for git repo https://github.com/jo3yzhu/too-many-lists written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/jo3yzhu/too-many-lists on toolchain 507271bc119683008ec719ecee48814e8ac86c65
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/jo3yzhu/too-many-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" "+507271bc119683008ec719ecee48814e8ac86c65" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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" "+507271bc119683008ec719ecee48814e8ac86c65" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d513a2ba17dfc2604efc4a76769c295d53b9e057997f9dc58ed53df14019e200
[INFO] running `Command { std: "docker" "start" "-a" "d513a2ba17dfc2604efc4a76769c295d53b9e057997f9dc58ed53df14019e200", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d513a2ba17dfc2604efc4a76769c295d53b9e057997f9dc58ed53df14019e200", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d513a2ba17dfc2604efc4a76769c295d53b9e057997f9dc58ed53df14019e200", kill_on_drop: false }`
[INFO] [stdout] d513a2ba17dfc2604efc4a76769c295d53b9e057997f9dc58ed53df14019e200
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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" "+507271bc119683008ec719ecee48814e8ac86c65" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a67c9dd48f82893bbe2e92c7809ec6218646750916d5213bdc527b96651a836e
[INFO] running `Command { std: "docker" "start" "-a" "a67c9dd48f82893bbe2e92c7809ec6218646750916d5213bdc527b96651a836e", kill_on_drop: false }`
[INFO] [stderr]     Checking too-many-lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `super::List`
[INFO] [stdout]   --> src/first.rs:60:9
[INFO] [stdout]    |
[INFO] [stdout] 60 |     use super::List;
[INFO] [stdout]    |         ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `super::List`
[INFO] [stdout]    --> src/second.rs:136:9
[INFO] [stdout]     |
[INFO] [stdout] 136 |     use super::List;
[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:13:12
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl<T> List<T> {
[INFO] [stdout]    | --------------- associated items in this implementation
[INFO] [stdout] 13 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 17 |     pub fn push(&mut self, i: T) {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 32 |     pub fn peek(&self) -> Option<&T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 36 |     pub fn peek_mut(&mut self) -> Option<&mut T> {
[INFO] [stdout]    |            ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `into_iter` is never used
[INFO] [stdout]   --> src/second.rs:62:12
[INFO] [stdout]    |
[INFO] [stdout] 61 | impl<T> List<T> {
[INFO] [stdout]    | --------------- method in this implementation
[INFO] [stdout] 62 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]    |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `iter` is never used
[INFO] [stdout]    --> src/second.rs:101:8
[INFO] [stdout]     |
[INFO] [stdout] 100 | impl<T> List<T> {
[INFO] [stdout]     | --------------- method in this implementation
[INFO] [stdout] 101 |     fn iter(&self) -> Iter<T> {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `IterMut` is never constructed
[INFO] [stdout]    --> src/second.rs:108:8
[INFO] [stdout]     |
[INFO] [stdout] 108 | struct IterMut<'a, T> {
[INFO] [stdout]     |        ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `iter_mut` is never used
[INFO] [stdout]    --> src/second.rs:128:8
[INFO] [stdout]     |
[INFO] [stdout] 126 | impl<'a, T> List<T> {
[INFO] [stdout]     | ------------------- method in this implementation
[INFO] [stdout] 127 |     // TODO: why use '_ instead of 'a, or won't compile?
[INFO] [stdout] 128 |     fn iter_mut(&mut self) -> IterMut<'_, T> {
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `plus_one` is never used
[INFO] [stdout]    --> src/second.rs:138:8
[INFO] [stdout]     |
[INFO] [stdout] 138 |     fn plus_one(i: i32) -> i32 {
[INFO] [stdout]     |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `List` is never constructed
[INFO] [stdout]   --> src/third.rs:10:8
[INFO] [stdout]    |
[INFO] [stdout] 10 | struct List<T> {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `prepend`, `tail`, and `head` are never used
[INFO] [stdout]   --> src/third.rs:15:12
[INFO] [stdout]    |
[INFO] [stdout] 14 | impl<T> List<T> {
[INFO] [stdout]    | --------------- associated items in this implementation
[INFO] [stdout] 15 |     pub fn new() -> Self {
[INFO] [stdout]    |            ^^^
[INFO] [stdout] ...
[INFO] [stdout] 19 |     pub fn prepend(&mut self, val: T) -> List<T> {
[INFO] [stdout]    |            ^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 34 |     pub fn tail(&mut self) -> List<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] ...
[INFO] [stdout] 40 |     pub fn head(&self) -> Option<&T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `iter` is never used
[INFO] [stdout]   --> src/third.rs:46:12
[INFO] [stdout]    |
[INFO] [stdout] 45 | impl<T> List<T> {
[INFO] [stdout]    | --------------- method in this implementation
[INFO] [stdout] 46 |     pub fn iter(&self) -> Iter<T> {
[INFO] [stdout]    |            ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/fourth.rs:22:8
[INFO] [stdout]    |
[INFO] [stdout] 21 | impl<T> Node<T> {
[INFO] [stdout]    | --------------- associated function in this implementation
[INFO] [stdout] 22 |     fn new(val: T) -> Rc<RefCell<Self>> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new`, `push_front`, `push_back`, `peek_front`, and `peek_back` are never used
[INFO] [stdout]    --> src/fourth.rs:32:8
[INFO] [stdout]     |
[INFO] [stdout]  31 | impl<T> List<T> {
[INFO] [stdout]     | --------------- associated items in this implementation
[INFO] [stdout]  32 |     fn new() -> List<T> {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] ...
[INFO] [stdout]  39 |     fn push_front(&mut self, val: T) {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout]  54 |     fn push_back(&mut self, val: T) {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 106 |     fn peek_front(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 112 |     fn peek_back(&self) -> Option<Ref<T>> {
[INFO] [stdout]     |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `into_iter` is never used
[INFO] [stdout]    --> src/fourth.rs:128:12
[INFO] [stdout]     |
[INFO] [stdout] 127 | impl<T> List<T> {
[INFO] [stdout]     | --------------- method in this implementation
[INFO] [stdout] 128 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated items `new` and `push` are never used
[INFO] [stdout]   --> src/fifth.rs:16:8
[INFO] [stdout]    |
[INFO] [stdout] 15 | impl<T> List<T> {
[INFO] [stdout]    | --------------- associated items in this implementation
[INFO] [stdout] 16 |     fn new() -> Self {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] ...
[INFO] [stdout] 23 |     fn push(&mut self, val: T) {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/second.rs:101:13
[INFO] [stdout]     |
[INFO] [stdout] 101 |     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]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 101 |     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/third.rs:46:17
[INFO] [stdout]    |
[INFO] [stdout] 46 |     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] 46 |     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/fourth.rs:106:19
[INFO] [stdout]     |
[INFO] [stdout] 106 |     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] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 106 |     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:112:18
[INFO] [stdout]     |
[INFO] [stdout] 112 |     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] 112 |     fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `into_iter` is never used
[INFO] [stdout]    --> src/fourth.rs:128:12
[INFO] [stdout]     |
[INFO] [stdout] 127 | impl<T> List<T> {
[INFO] [stdout]     | --------------- method in this implementation
[INFO] [stdout] 128 |     pub fn into_iter(self) -> IntoIter<T> {
[INFO] [stdout]     |            ^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]    --> src/second.rs:101:13
[INFO] [stdout]     |
[INFO] [stdout] 101 |     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]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 101 |     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/third.rs:46:17
[INFO] [stdout]    |
[INFO] [stdout] 46 |     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] 46 |     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/fourth.rs:106:19
[INFO] [stdout]     |
[INFO] [stdout] 106 |     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] help: use `'_` for type paths
[INFO] [stdout]     |
[INFO] [stdout] 106 |     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:112:18
[INFO] [stdout]     |
[INFO] [stdout] 112 |     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] 112 |     fn peek_back(&self) -> Option<Ref<'_, T>> {
[INFO] [stdout]     |                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.21s
[INFO] running `Command { std: "docker" "inspect" "a67c9dd48f82893bbe2e92c7809ec6218646750916d5213bdc527b96651a836e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a67c9dd48f82893bbe2e92c7809ec6218646750916d5213bdc527b96651a836e", kill_on_drop: false }`
[INFO] [stdout] a67c9dd48f82893bbe2e92c7809ec6218646750916d5213bdc527b96651a836e
