[INFO] cloning repository https://github.com/juliob29/Rust-Doubly-Linked-List
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/juliob29/Rust-Doubly-Linked-List" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjuliob29%2FRust-Doubly-Linked-List", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjuliob29%2FRust-Doubly-Linked-List'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f2b03c65ec30a503bc26bdd76001aa12696e550a
[INFO] checking juliob29/Rust-Doubly-Linked-List against try#3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f for pr-87248
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjuliob29%2FRust-Doubly-Linked-List" "/workspace/builds/worker-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/juliob29/Rust-Doubly-Linked-List on toolchain 3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/juliob29/Rust-Doubly-Linked-List
[INFO] finished tweaking git repo https://github.com/juliob29/Rust-Doubly-Linked-List
[INFO] tweaked toml for git repo https://github.com/juliob29/Rust-Doubly-Linked-List written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/juliob29/Rust-Doubly-Linked-List already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 146174948c3987b5ee3e1a0dde1777081ff1cf6912096a17e9dc4a28afb237df
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "146174948c3987b5ee3e1a0dde1777081ff1cf6912096a17e9dc4a28afb237df", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "146174948c3987b5ee3e1a0dde1777081ff1cf6912096a17e9dc4a28afb237df", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "146174948c3987b5ee3e1a0dde1777081ff1cf6912096a17e9dc4a28afb237df", kill_on_drop: false }`
[INFO] [stdout] 146174948c3987b5ee3e1a0dde1777081ff1cf6912096a17e9dc4a28afb237df
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+3e59a8c2f14152ccc92a6c079f592dc2dc6fa93f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 795899486bc33e899e23c5c39698d33fe39c29c20b4dfe3b0c726b536ea3422f
[INFO] running `Command { std: "docker" "start" "-a" "795899486bc33e899e23c5c39698d33fe39c29c20b4dfe3b0c726b536ea3422f", kill_on_drop: false }`
[INFO] [stderr]     Checking doubly-linked-list v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `fmt::Display`
[INFO] [stdout]  --> src/main.rs:6:26
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::{cell::RefCell, fmt::Display, rc::Rc}; 
[INFO] [stdout]   |                          ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:29:11
[INFO] [stdout]    |
[INFO] [stdout] 29 |       let mut new_node = Rc::new(RefCell::new(Node{
[INFO] [stdout]    |           ----^^^^^^^^
[INFO] [stdout]    |           |
[INFO] [stdout]    |           help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `fmt::Display`
[INFO] [stdout]  --> src/main.rs:6:26
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::{cell::RefCell, fmt::Display, rc::Rc}; 
[INFO] [stdout]   |                          ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:29:11
[INFO] [stdout]    |
[INFO] [stdout] 29 |       let mut new_node = Rc::new(RefCell::new(Node{
[INFO] [stdout]    |           ----^^^^^^^^
[INFO] [stdout]    |           |
[INFO] [stdout]    |           help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `printList` should have a snake case name
[INFO] [stdout]   --> src/main.rs:48:6
[INFO] [stdout]    |
[INFO] [stdout] 48 |   fn printList(&self) {
[INFO] [stdout]    |      ^^^^^^^^^ help: convert the identifier to snake case: `print_list`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `printBack` should have a snake case name
[INFO] [stdout]   --> src/main.rs:58:6
[INFO] [stdout]    |
[INFO] [stdout] 58 |   fn printBack(&self) {
[INFO] [stdout]    |      ^^^^^^^^^ help: convert the identifier to snake case: `print_back`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `printList` should have a snake case name
[INFO] [stdout]   --> src/main.rs:48:6
[INFO] [stdout]    |
[INFO] [stdout] 48 |   fn printList(&self) {
[INFO] [stdout]    |      ^^^^^^^^^ help: convert the identifier to snake case: `print_list`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `printBack` should have a snake case name
[INFO] [stdout]   --> src/main.rs:58:6
[INFO] [stdout]    |
[INFO] [stdout] 58 |   fn printBack(&self) {
[INFO] [stdout]    |      ^^^^^^^^^ help: convert the identifier to snake case: `print_back`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.85s
[INFO] running `Command { std: "docker" "inspect" "795899486bc33e899e23c5c39698d33fe39c29c20b4dfe3b0c726b536ea3422f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "795899486bc33e899e23c5c39698d33fe39c29c20b4dfe3b0c726b536ea3422f", kill_on_drop: false }`
[INFO] [stdout] 795899486bc33e899e23c5c39698d33fe39c29c20b4dfe3b0c726b536ea3422f