[INFO] cloning repository https://github.com/alvaroclementev/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/alvaroclementev/too-many-lists" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falvaroclementev%2Ftoo-many-lists", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falvaroclementev%2Ftoo-many-lists'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7911c46d7f4451d7f2013377c80d482cf0df6ff5
[INFO] checking alvaroclementev/too-many-lists against try#0611f7de057c584b8771102fde7aed6c70c71d3b for pr-146440
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falvaroclementev%2Ftoo-many-lists" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/alvaroclementev/too-many-lists
[INFO] finished tweaking git repo https://github.com/alvaroclementev/too-many-lists
[INFO] tweaked toml for git repo https://github.com/alvaroclementev/too-many-lists written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/alvaroclementev/too-many-lists on toolchain 0611f7de057c584b8771102fde7aed6c70c71d3b
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/alvaroclementev/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" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1445ca86465ace24f6b71cfc081c3e4698bb6f835e4c19a86c25459e5e1ee19d
[INFO] running `Command { std: "docker" "start" "-a" "1445ca86465ace24f6b71cfc081c3e4698bb6f835e4c19a86c25459e5e1ee19d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1445ca86465ace24f6b71cfc081c3e4698bb6f835e4c19a86c25459e5e1ee19d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1445ca86465ace24f6b71cfc081c3e4698bb6f835e4c19a86c25459e5e1ee19d", kill_on_drop: false }`
[INFO] [stdout] 1445ca86465ace24f6b71cfc081c3e4698bb6f835e4c19a86c25459e5e1ee19d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+0611f7de057c584b8771102fde7aed6c70c71d3b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] accec3506ee3dff9c5952b10a34be513e96e5a4e271ce8c949b313dcb6d22b9b
[INFO] running `Command { std: "docker" "start" "-a" "accec3506ee3dff9c5952b10a34be513e96e5a4e271ce8c949b313dcb6d22b9b", kill_on_drop: false }`
[INFO] [stderr]     Checking lists v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: struct `List` is never constructed
[INFO] [stdout]  --> src/fourth.rs:4:12
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub struct List<T> {
[INFO] [stdout]   |            ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout]   = note: `#[deny(unused_unconstructable_pub_struct)]` (part of `#[deny(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: struct `IntoIter` is never constructed
[INFO] [stdout]    --> src/fourth.rs:131:12
[INFO] [stdout]     |
[INFO] [stdout] 131 | pub struct IntoIter<T>(List<T>);
[INFO] [stdout]     |            ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `pub` struct has private fields, no public constructor, and is not otherwise reachable through the external API, so consider providing a public constructor or removing it
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `new` is never used
[INFO] [stdout]   --> src/fourth.rs:28:8
[INFO] [stdout]    |
[INFO] [stdout] 27 | impl<T> List<T> {
[INFO] [stdout]    | --------------- associated function in this implementation
[INFO] [stdout] 28 |     fn new() -> Self {
[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/fourth.rs:74:23
[INFO] [stdout]    |
[INFO] [stdout] 74 |     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] 74 |     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:111:22
[INFO] [stdout]     |
[INFO] [stdout] 111 |     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] 111 |     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:117:26
[INFO] [stdout]     |
[INFO] [stdout] 117 |     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] 117 |     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:123:27
[INFO] [stdout]     |
[INFO] [stdout] 123 |     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] 123 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `lists` (lib) due to 2 previous errors; 5 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: hiding a lifetime that's elided elsewhere is confusing
[INFO] [stdout]   --> src/fourth.rs:74:23
[INFO] [stdout]    |
[INFO] [stdout] 74 |     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] 74 |     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:111:22
[INFO] [stdout]     |
[INFO] [stdout] 111 |     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] 111 |     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:117:26
[INFO] [stdout]     |
[INFO] [stdout] 117 |     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] 117 |     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:123:27
[INFO] [stdout]     |
[INFO] [stdout] 123 |     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] 123 |     pub fn peek_front_mut(&mut self) -> Option<RefMut<'_, T>> {
[INFO] [stdout]     |                                                       +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "accec3506ee3dff9c5952b10a34be513e96e5a4e271ce8c949b313dcb6d22b9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "accec3506ee3dff9c5952b10a34be513e96e5a4e271ce8c949b313dcb6d22b9b", kill_on_drop: false }`
[INFO] [stdout] accec3506ee3dff9c5952b10a34be513e96e5a4e271ce8c949b313dcb6d22b9b
