[INFO] cloning repository https://github.com/p870613/rust-learn
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/p870613/rust-learn" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fp870613%2Frust-learn", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fp870613%2Frust-learn'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 59ce988c1d225b430c0f293c2f0e27fed1e28cfc
[INFO] checking p870613/rust-learn against try#45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4 for pr-83744
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fp870613%2Frust-learn" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/p870613/rust-learn on toolchain 45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/p870613/rust-learn
[INFO] finished tweaking git repo https://github.com/p870613/rust-learn
[INFO] tweaked toml for git repo https://github.com/p870613/rust-learn written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/p870613/rust-learn already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] eebcd67ba1e63c7b74e79cf4659b49b185d452704dab000dde8847d54658af7e
[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" "eebcd67ba1e63c7b74e79cf4659b49b185d452704dab000dde8847d54658af7e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "eebcd67ba1e63c7b74e79cf4659b49b185d452704dab000dde8847d54658af7e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "eebcd67ba1e63c7b74e79cf4659b49b185d452704dab000dde8847d54658af7e", kill_on_drop: false }`
[INFO] [stdout] eebcd67ba1e63c7b74e79cf4659b49b185d452704dab000dde8847d54658af7e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+45d8b6e68beee1c9c1ce92ae258a7e02f8f13aa4" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a7f12f2223facd2f0a9b724f31128069e180e01a7655236fa4582c6b10de4efb
[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" "a7f12f2223facd2f0a9b724f31128069e180e01a7655236fa4582c6b10de4efb", kill_on_drop: false }`
[INFO] [stderr]     Checking double_linked_list v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: value assigned to `tmp` is never read
[INFO] [stdout]    --> src/main.rs:236:13
[INFO] [stdout]     |
[INFO] [stdout] 236 |     let mut tmp = None;
[INFO] [stdout]     |             ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `tmp2` is never read
[INFO] [stdout]    --> src/main.rs:237:13
[INFO] [stdout]     |
[INFO] [stdout] 237 |     let mut tmp2 = None;
[INFO] [stdout]     |             ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `tmp3` is never read
[INFO] [stdout]    --> src/main.rs:238:13
[INFO] [stdout]     |
[INFO] [stdout] 238 |     let mut tmp3 = None;
[INFO] [stdout]     |             ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `del`
[INFO] [stdout]   --> src/main.rs:86:21
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 let del = node.borrow_mut().next.take();
[INFO] [stdout]    |                     ^^^ help: if this is intentional, prefix it with an underscore: `_del`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `erase`
[INFO] [stdout]    --> src/main.rs:191:8
[INFO] [stdout]     |
[INFO] [stdout] 191 |     fn erase() {}
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `node_Rc` should have a snake case name
[INFO] [stdout]   --> src/main.rs:24:26
[INFO] [stdout]    |
[INFO] [stdout] 24 |                     Some(node_Rc) => Some(Rc::clone(&node_Rc)),
[INFO] [stdout]    |                          ^^^^^^^ help: convert the identifier to snake case: `node_rc`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `tmp` is never read
[INFO] [stdout]    --> src/main.rs:236:13
[INFO] [stdout]     |
[INFO] [stdout] 236 |     let mut tmp = None;
[INFO] [stdout]     |             ^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `tmp2` is never read
[INFO] [stdout]    --> src/main.rs:237:13
[INFO] [stdout]     |
[INFO] [stdout] 237 |     let mut tmp2 = None;
[INFO] [stdout]     |             ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `tmp3` is never read
[INFO] [stdout]    --> src/main.rs:238:13
[INFO] [stdout]     |
[INFO] [stdout] 238 |     let mut tmp3 = None;
[INFO] [stdout]     |             ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `del`
[INFO] [stdout]   --> src/main.rs:86:21
[INFO] [stdout]    |
[INFO] [stdout] 86 |                 let del = node.borrow_mut().next.take();
[INFO] [stdout]    |                     ^^^ help: if this is intentional, prefix it with an underscore: `_del`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `erase`
[INFO] [stdout]    --> src/main.rs:191:8
[INFO] [stdout]     |
[INFO] [stdout] 191 |     fn erase() {}
[INFO] [stdout]     |        ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `node_Rc` should have a snake case name
[INFO] [stdout]   --> src/main.rs:24:26
[INFO] [stdout]    |
[INFO] [stdout] 24 |                     Some(node_Rc) => Some(Rc::clone(&node_Rc)),
[INFO] [stdout]    |                          ^^^^^^^ help: convert the identifier to snake case: `node_rc`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.34s
[INFO] running `Command { std: "docker" "inspect" "a7f12f2223facd2f0a9b724f31128069e180e01a7655236fa4582c6b10de4efb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a7f12f2223facd2f0a9b724f31128069e180e01a7655236fa4582c6b10de4efb", kill_on_drop: false }`
[INFO] [stdout] a7f12f2223facd2f0a9b724f31128069e180e01a7655236fa4582c6b10de4efb