[INFO] cloning repository https://github.com/primi-duan/dlink_list
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/primi-duan/dlink_list" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprimi-duan%2Fdlink_list", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprimi-duan%2Fdlink_list'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 633bbc95d1d3bd2fa0dda94ca9eb528bf61dd201
[INFO] testing primi-duan/dlink_list against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprimi-duan%2Fdlink_list" "/workspace/builds/worker-0/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/primi-duan/dlink_list on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/primi-duan/dlink_list
[INFO] finished tweaking git repo https://github.com/primi-duan/dlink_list
[INFO] tweaked toml for git repo https://github.com/primi-duan/dlink_list written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/primi-duan/dlink_list already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "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] 492438315e9c4a5e9a333c774fbf0c347cc9e40f7444c28da4604aecc2275ee1
[INFO] running `Command { std: "docker" "start" "-a" "492438315e9c4a5e9a333c774fbf0c347cc9e40f7444c28da4604aecc2275ee1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "492438315e9c4a5e9a333c774fbf0c347cc9e40f7444c28da4604aecc2275ee1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "492438315e9c4a5e9a333c774fbf0c347cc9e40f7444c28da4604aecc2275ee1", kill_on_drop: false }`
[INFO] [stdout] 492438315e9c4a5e9a333c774fbf0c347cc9e40f7444c28da4604aecc2275ee1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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=warn" "-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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5ab2b3883698ee1aa5be6269121b0b5461e7878699807e0f5281aef0c48a4c28
[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" "5ab2b3883698ee1aa5be6269121b0b5461e7878699807e0f5281aef0c48a4c28", kill_on_drop: false }`
[INFO] [stderr]    Compiling link_list_test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: type `Node_st` should have an upper camel case name
[INFO] [stdout]   --> src/dlink_list.rs:14:12
[INFO] [stdout]    |
[INFO] [stdout] 14 |     struct Node_st<T: Display> {
[INFO] [stdout]    |            ^^^^^^^ help: convert the identifier to upper camel case: `NodeSt`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: module `DLINK_LIST` should have a snake case name
[INFO] [stdout]  --> src/dlink_list.rs:1:9
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub mod DLINK_LIST {
[INFO] [stdout]   |         ^^^^^^^^^^ help: convert the identifier to snake case: `dlink_list`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:41:13
[INFO] [stdout]    |
[INFO] [stdout] 41 |             write!(f, "------------show list------------\n");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:42:13
[INFO] [stdout]    |
[INFO] [stdout] 42 |             write!(f, "length: {}\n", self.len);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:43:13
[INFO] [stdout]    |
[INFO] [stdout] 43 |             write!(f, "capacity: {}\n", self.capacity);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:45:17
[INFO] [stdout]    |
[INFO] [stdout] 45 |                 write!(f, "[empty]");
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:51:13
[INFO] [stdout]    |
[INFO] [stdout] 51 |             write!(f, "node value {}", tmp_head.borrow().element);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:54:17
[INFO] [stdout]    |
[INFO] [stdout] 54 |                 write!(f, " -> ");
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:56:17
[INFO] [stdout]    |
[INFO] [stdout] 56 |                 write!(f, "node value {}", next_t.borrow().element);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 9 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.27s
[INFO] running `Command { std: "docker" "inspect" "5ab2b3883698ee1aa5be6269121b0b5461e7878699807e0f5281aef0c48a4c28", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5ab2b3883698ee1aa5be6269121b0b5461e7878699807e0f5281aef0c48a4c28", kill_on_drop: false }`
[INFO] [stdout] 5ab2b3883698ee1aa5be6269121b0b5461e7878699807e0f5281aef0c48a4c28
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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=warn" "-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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen" "--no-run" "--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] 705ee5aac5253906c70b01b1af8be7a86fd1e08dddecc0eb1d45a2d6f462d9dc
[INFO] running `Command { std: "docker" "start" "-a" "705ee5aac5253906c70b01b1af8be7a86fd1e08dddecc0eb1d45a2d6f462d9dc", kill_on_drop: false }`
[INFO] [stderr]    Compiling link_list_test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: type `Node_st` should have an upper camel case name
[INFO] [stdout]   --> src/dlink_list.rs:14:12
[INFO] [stdout]    |
[INFO] [stdout] 14 |     struct Node_st<T: Display> {
[INFO] [stdout]    |            ^^^^^^^ help: convert the identifier to upper camel case: `NodeSt`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: module `DLINK_LIST` should have a snake case name
[INFO] [stdout]  --> src/dlink_list.rs:1:9
[INFO] [stdout]   |
[INFO] [stdout] 1 | pub mod DLINK_LIST {
[INFO] [stdout]   |         ^^^^^^^^^^ help: convert the identifier to snake case: `dlink_list`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:41:13
[INFO] [stdout]    |
[INFO] [stdout] 41 |             write!(f, "------------show list------------\n");
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:42:13
[INFO] [stdout]    |
[INFO] [stdout] 42 |             write!(f, "length: {}\n", self.len);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:43:13
[INFO] [stdout]    |
[INFO] [stdout] 43 |             write!(f, "capacity: {}\n", self.capacity);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:45:17
[INFO] [stdout]    |
[INFO] [stdout] 45 |                 write!(f, "[empty]");
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:51:13
[INFO] [stdout]    |
[INFO] [stdout] 51 |             write!(f, "node value {}", tmp_head.borrow().element);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:54:17
[INFO] [stdout]    |
[INFO] [stdout] 54 |                 write!(f, " -> ");
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/dlink_list.rs:56:17
[INFO] [stdout]    |
[INFO] [stdout] 56 |                 write!(f, "node value {}", next_t.borrow().element);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 9 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.99s
[INFO] running `Command { std: "docker" "inspect" "705ee5aac5253906c70b01b1af8be7a86fd1e08dddecc0eb1d45a2d6f462d9dc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "705ee5aac5253906c70b01b1af8be7a86fd1e08dddecc0eb1d45a2d6f462d9dc", kill_on_drop: false }`
[INFO] [stdout] 705ee5aac5253906c70b01b1af8be7a86fd1e08dddecc0eb1d45a2d6f462d9dc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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=warn" "-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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] dfb6a429d08078d0fc1f5f75272ffa7f27194029aac3734ff798adace31becce
[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" "dfb6a429d08078d0fc1f5f75272ffa7f27194029aac3734ff798adace31becce", kill_on_drop: false }`
[INFO] [stderr] warning: type `Node_st` should have an upper camel case name
[INFO] [stderr]   --> src/dlink_list.rs:14:12
[INFO] [stderr]    |
[INFO] [stderr] 14 |     struct Node_st<T: Display> {
[INFO] [stderr]    |            ^^^^^^^ help: convert the identifier to upper camel case: `NodeSt`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(non_camel_case_types)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: module `DLINK_LIST` should have a snake case name
[INFO] [stderr]  --> src/dlink_list.rs:1:9
[INFO] [stderr]   |
[INFO] [stderr] 1 | pub mod DLINK_LIST {
[INFO] [stderr]   |         ^^^^^^^^^^ help: convert the identifier to snake case: `dlink_list`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/dlink_list.rs:41:13
[INFO] [stderr]    |
[INFO] [stderr] 41 |             write!(f, "------------show list------------\n");
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/dlink_list.rs:42:13
[INFO] [stderr]    |
[INFO] [stderr] 42 |             write!(f, "length: {}\n", self.len);
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/dlink_list.rs:43:13
[INFO] [stderr]    |
[INFO] [stderr] 43 |             write!(f, "capacity: {}\n", self.capacity);
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/dlink_list.rs:45:17
[INFO] [stderr]    |
[INFO] [stderr] 45 |                 write!(f, "[empty]");
[INFO] [stderr]    |                 ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/dlink_list.rs:51:13
[INFO] [stderr]    |
[INFO] [stderr] 51 |             write!(f, "node value {}", tmp_head.borrow().element);
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/dlink_list.rs:54:17
[INFO] [stderr]    |
[INFO] [stderr] 54 |                 write!(f, " -> ");
[INFO] [stderr]    |                 ^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/dlink_list.rs:56:17
[INFO] [stderr]    |
[INFO] [stderr] 56 |                 write!(f, "node value {}", next_t.borrow().element);
[INFO] [stderr]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stderr] 
[INFO] [stderr] warning: `link_list_test` (bin "link_list_test" test) generated 9 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/link_list_test-a0aa1d957fff6fab)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "dfb6a429d08078d0fc1f5f75272ffa7f27194029aac3734ff798adace31becce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dfb6a429d08078d0fc1f5f75272ffa7f27194029aac3734ff798adace31becce", kill_on_drop: false }`
[INFO] [stdout] dfb6a429d08078d0fc1f5f75272ffa7f27194029aac3734ff798adace31becce