[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#4a04890980766cc79878135f5ade8c0c4321e943 for pr-65819
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fp870613%2Frust-learn" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/p870613/rust-learn on toolchain 4a04890980766cc79878135f5ade8c0c4321e943
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4a04890980766cc79878135f5ade8c0c4321e943" "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-2/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" "+4a04890980766cc79878135f5ade8c0c4321e943" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "rustops/crates-build-env@sha256:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+4a04890980766cc79878135f5ade8c0c4321e943" "metadata" "--no-deps" "--format-version=1", 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] 3079904ad5e881d49c4b6a12c1be7356a0cdd04c08199dd7ab98534fbbd478bc
[INFO] running `Command { std: "docker" "start" "-a" "3079904ad5e881d49c4b6a12c1be7356a0cdd04c08199dd7ab98534fbbd478bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3079904ad5e881d49c4b6a12c1be7356a0cdd04c08199dd7ab98534fbbd478bc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3079904ad5e881d49c4b6a12c1be7356a0cdd04c08199dd7ab98534fbbd478bc", kill_on_drop: false }`
[INFO] [stdout] 3079904ad5e881d49c4b6a12c1be7356a0cdd04c08199dd7ab98534fbbd478bc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "rustops/crates-build-env@sha256:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+4a04890980766cc79878135f5ade8c0c4321e943" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d57d3510b507543a1ca1edd9109bcfe7e978afd76f5b5aa835291c6cab58f907
[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" "d57d3510b507543a1ca1edd9109bcfe7e978afd76f5b5aa835291c6cab58f907", 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 0.57s
[INFO] running `Command { std: "docker" "inspect" "d57d3510b507543a1ca1edd9109bcfe7e978afd76f5b5aa835291c6cab58f907", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d57d3510b507543a1ca1edd9109bcfe7e978afd76f5b5aa835291c6cab58f907", kill_on_drop: false }`
[INFO] [stdout] d57d3510b507543a1ca1edd9109bcfe7e978afd76f5b5aa835291c6cab58f907