[INFO] cloning repository https://github.com/EdenCao/rust_learning
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/EdenCao/rust_learning" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEdenCao%2Frust_learning", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEdenCao%2Frust_learning'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3b85aa524f292dd7b9939ed7d5de8b6456618f9f
[INFO] checking EdenCao/rust_learning/3b85aa524f292dd7b9939ed7d5de8b6456618f9f against master#f609b7e0586f81fefb3523e3e17adf779ac416be for pr-129466-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FEdenCao%2Frust_learning" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/EdenCao/rust_learning on toolchain f609b7e0586f81fefb3523e3e17adf779ac416be
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+f609b7e0586f81fefb3523e3e17adf779ac416be" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/EdenCao/rust_learning
[INFO] finished tweaking git repo https://github.com/EdenCao/rust_learning
[INFO] tweaked toml for git repo https://github.com/EdenCao/rust_learning written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/EdenCao/rust_learning 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" "+f609b7e0586f81fefb3523e3e17adf779ac416be" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2021
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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:ceb6ea022f8a89cebbe621bb4987e73a935bd40dfbb726f832cfff4742a5b95a" "/opt/rustwide/cargo-home/bin/cargo" "+f609b7e0586f81fefb3523e3e17adf779ac416be" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9ec74c994c8057a39524d3fbeed2110ab2e1827ac99d52502cb663a5496c6a1d
[INFO] running `Command { std: "docker" "start" "-a" "9ec74c994c8057a39524d3fbeed2110ab2e1827ac99d52502cb663a5496c6a1d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9ec74c994c8057a39524d3fbeed2110ab2e1827ac99d52502cb663a5496c6a1d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9ec74c994c8057a39524d3fbeed2110ab2e1827ac99d52502cb663a5496c6a1d", kill_on_drop: false }`
[INFO] [stdout] 9ec74c994c8057a39524d3fbeed2110ab2e1827ac99d52502cb663a5496c6a1d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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:ceb6ea022f8a89cebbe621bb4987e73a935bd40dfbb726f832cfff4742a5b95a" "/opt/rustwide/cargo-home/bin/cargo" "+f609b7e0586f81fefb3523e3e17adf779ac416be" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] dff51d593e32f1f899f92c316987bf34190b6ebe86e170aaa68e8b201f708909
[INFO] running `Command { std: "docker" "start" "-a" "dff51d593e32f1f899f92c316987bf34190b6ebe86e170aaa68e8b201f708909", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2021
[INFO] [stderr]     Checking rand_core v0.3.0
[INFO] [stderr]     Checking libc v0.2.43
[INFO] [stderr]     Checking rand_core v0.2.2
[INFO] [stderr]     Checking rand v0.5.5
[INFO] [stderr]     Checking rust_learning v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/struct_ex.rs:17:3
[INFO] [stdout]    |
[INFO] [stdout] 17 |   ///
[INFO] [stdout]    |   ^^^
[INFO] [stdout] 18 |   let rect1 = (30, 50);
[INFO] [stdout]    |   --------------------- rustdoc does not generate documentation for statements
[INFO] [stdout]    |
[INFO] [stdout]    = help: use `//` for a plain comment
[INFO] [stdout]    = note: `#[warn(unused_doc_comments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s6`
[INFO] [stdout]   --> src/owner.rs:19:7
[INFO] [stdout]    |
[INFO] [stdout] 19 |   let s6 = s5;
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s6`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `gives_ownership` is never used
[INFO] [stdout]   --> src/owner.rs:37:4
[INFO] [stdout]    |
[INFO] [stdout] 37 | fn gives_ownership() -> String {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/match.rs:25:7
[INFO] [stdout]    |
[INFO] [stdout] 25 |   let six = plus_one(five);
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/match.rs:26:7
[INFO] [stdout]    |
[INFO] [stdout] 26 |   let none = plus_one(None);
[INFO] [stdout]    |       ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Penny`, `Nickel`, and `Dime` are never constructed
[INFO] [stdout]  --> src/match.rs:2:3
[INFO] [stdout]   |
[INFO] [stdout] 1 | enum Coin {
[INFO] [stdout]   |      ---- variants in this enum
[INFO] [stdout] 2 |   Penny,
[INFO] [stdout]   |   ^^^^^
[INFO] [stdout] 3 |   Nickel,
[INFO] [stdout]   |   ^^^^^^
[INFO] [stdout] 4 |   Dime,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `Alabama` is never constructed
[INFO] [stdout]   --> src/match.rs:10:3
[INFO] [stdout]    |
[INFO] [stdout] 9  | enum UsState {
[INFO] [stdout]    |      ------- variant in this enum
[INFO] [stdout] 10 |   Alabama,
[INFO] [stdout]    |   ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `UsState` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]  --> src/rc.rs:7:10
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons(Rc<RefCell<i32>>, Rc<List>),
[INFO] [stdout]   |     ---- ^^^^^^^^^^^^^^^^  ^^^^^^^^
[INFO] [stdout]   |     |
[INFO] [stdout]   |     fields in this variant
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons((), ()),
[INFO] [stdout]   |          ~~  ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/cycle_ref.rs:7:10
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons(i32, RefCell<Rc<List>>),
[INFO] [stdout]   |     ---- ^^^
[INFO] [stdout]   |     |
[INFO] [stdout]   |     field in this variant
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons((), RefCell<Rc<List>>),
[INFO] [stdout]   |          ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/blog.rs:2:21
[INFO] [stdout]   |
[INFO] [stdout] 2 |   state: Option<Box<State>>,
[INFO] [stdout]   |                     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 2 |   state: Option<Box<dyn State>>,
[INFO] [stdout]   |                     +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:33:45
[INFO] [stdout]    |
[INFO] [stdout] 33 |   fn request_review(self: Box<Self>) -> Box<State>;
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 33 |   fn request_review(self: Box<Self>) -> Box<dyn State>;
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:34:38
[INFO] [stdout]    |
[INFO] [stdout] 34 |   fn approve(self: Box<Self>) -> Box<State>;
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 34 |   fn approve(self: Box<Self>) -> Box<dyn State>;
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:40:45
[INFO] [stdout]    |
[INFO] [stdout] 40 |   fn request_review(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 40 |   fn request_review(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:44:38
[INFO] [stdout]    |
[INFO] [stdout] 44 |   fn approve(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 44 |   fn approve(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:52:45
[INFO] [stdout]    |
[INFO] [stdout] 52 |   fn request_review(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 52 |   fn request_review(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:56:38
[INFO] [stdout]    |
[INFO] [stdout] 56 |   fn approve(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 56 |   fn approve(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:64:45
[INFO] [stdout]    |
[INFO] [stdout] 64 |   fn request_review(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 64 |   fn request_review(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:68:38
[INFO] [stdout]    |
[INFO] [stdout] 68 |   fn approve(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 68 |   fn approve(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/blog.rs:2:21
[INFO] [stdout]   |
[INFO] [stdout] 2 |   state: Option<Box<State>>,
[INFO] [stdout]   |                     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 2 |   state: Option<Box<dyn State>>,
[INFO] [stdout]   |                     +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:33:45
[INFO] [stdout]    |
[INFO] [stdout] 33 |   fn request_review(self: Box<Self>) -> Box<State>;
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 33 |   fn request_review(self: Box<Self>) -> Box<dyn State>;
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::time::Duration`
[INFO] [stdout]  --> src/multiple_thread.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::time::Duration;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:34:38
[INFO] [stdout]    |
[INFO] [stdout] 34 |   fn approve(self: Box<Self>) -> Box<State>;
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 34 |   fn approve(self: Box<Self>) -> Box<dyn State>;
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:40:45
[INFO] [stdout]    |
[INFO] [stdout] 40 |   fn request_review(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 40 |   fn request_review(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:44:38
[INFO] [stdout]    |
[INFO] [stdout] 44 |   fn approve(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 44 |   fn approve(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:52:45
[INFO] [stdout]    |
[INFO] [stdout] 52 |   fn request_review(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 52 |   fn request_review(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/enum.rs:20:7
[INFO] [stdout]    |
[INFO] [stdout] 20 |   let six = IpAddrKind::V6;
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/enum.rs:27:7
[INFO] [stdout]    |
[INFO] [stdout] 27 |   let home = IpAddr {
[INFO] [stdout]    |       ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `post`
[INFO] [stdout]   --> src/blog.rs:30:25
[INFO] [stdout]    |
[INFO] [stdout] 30 |   fn content<'a>(&self, post: &'a Post) -> &'a str {
[INFO] [stdout]    |                         ^^^^ help: if this is intentional, prefix it with an underscore: `_post`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `op_type`
[INFO] [stdout]   --> src/enum.rs:35:10
[INFO] [stdout]    |
[INFO] [stdout] 35 | fn route(op_type: IpAddrKind) { }
[INFO] [stdout]    |          ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_op_type`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `request_review` is never used
[INFO] [stdout]   --> src/blog.rs:33:6
[INFO] [stdout]    |
[INFO] [stdout] 29 | trait State {
[INFO] [stdout]    |       ----- method in this trait
[INFO] [stdout] ...
[INFO] [stdout] 33 |   fn request_review(self: Box<Self>) -> Box<State>;
[INFO] [stdout]    |      ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `kind` and `address` are never read
[INFO] [stdout]   --> src/enum.rs:14:3
[INFO] [stdout]    |
[INFO] [stdout] 13 | struct IpAddr {
[INFO] [stdout]    |        ------ fields in this struct
[INFO] [stdout] 14 |   kind: IpAddrKind,
[INFO] [stdout]    |   ^^^^
[INFO] [stdout] 15 |   address: String
[INFO] [stdout]    |   ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `PendingReview` is never constructed
[INFO] [stdout]   --> src/blog.rs:49:8
[INFO] [stdout]    |
[INFO] [stdout] 49 | struct PendingReview{}
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Published` is never constructed
[INFO] [stdout]   --> src/blog.rs:61:8
[INFO] [stdout]    |
[INFO] [stdout] 61 | struct Published {}
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:56:38
[INFO] [stdout]    |
[INFO] [stdout] 56 |   fn approve(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 56 |   fn approve(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:64:45
[INFO] [stdout]    |
[INFO] [stdout] 64 |   fn request_review(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                             ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 64 |   fn request_review(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/blog.rs:68:38
[INFO] [stdout]    |
[INFO] [stdout] 68 |   fn approve(self: Box<Self>) -> Box<State> {
[INFO] [stdout]    |                                      ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 68 |   fn approve(self: Box<Self>) -> Box<dyn State> {
[INFO] [stdout]    |                                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `count` is assigned to, but never used
[INFO] [stdout]   --> src/iflet.rs:20:11
[INFO] [stdout]    |
[INFO] [stdout] 20 |   let mut count = 0;
[INFO] [stdout]    |           ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_count` instead
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `count` is never read
[INFO] [stdout]   --> src/iflet.rs:25:5
[INFO] [stdout]    |
[INFO] [stdout] 25 |     count += 1;
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `post`
[INFO] [stdout]   --> src/blog.rs:30:25
[INFO] [stdout]    |
[INFO] [stdout] 30 |   fn content<'a>(&self, post: &'a Post) -> &'a str {
[INFO] [stdout]    |                         ^^^^ help: if this is intentional, prefix it with an underscore: `_post`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Penny`, `Nickel`, and `Dime` are never constructed
[INFO] [stdout]  --> src/iflet.rs:2:3
[INFO] [stdout]   |
[INFO] [stdout] 1 | enum Coin {
[INFO] [stdout]   |      ---- variants in this enum
[INFO] [stdout] 2 |   Penny,
[INFO] [stdout]   |   ^^^^^
[INFO] [stdout] 3 |   Nickel,
[INFO] [stdout]   |   ^^^^^^
[INFO] [stdout] 4 |   Dime,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `Alabama` is never constructed
[INFO] [stdout]   --> src/iflet.rs:10:3
[INFO] [stdout]    |
[INFO] [stdout] 9  | enum UsState {
[INFO] [stdout]    |      ------- variant in this enum
[INFO] [stdout] 10 |   Alabama,
[INFO] [stdout]    |   ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `UsState` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `request_review` is never used
[INFO] [stdout]   --> src/blog.rs:33:6
[INFO] [stdout]    |
[INFO] [stdout] 29 | trait State {
[INFO] [stdout]    |       ----- method in this trait
[INFO] [stdout] ...
[INFO] [stdout] 33 |   fn request_review(self: Box<Self>) -> Box<State>;
[INFO] [stdout]    |      ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `PendingReview` is never constructed
[INFO] [stdout]   --> src/blog.rs:49:8
[INFO] [stdout]    |
[INFO] [stdout] 49 | struct PendingReview{}
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Published` is never constructed
[INFO] [stdout]   --> src/blog.rs:61:8
[INFO] [stdout]    |
[INFO] [stdout] 61 | struct Published {}
[INFO] [stdout]    |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/match.rs:25:7
[INFO] [stdout]    |
[INFO] [stdout] 25 |   let six = plus_one(five);
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]   --> src/match.rs:26:7
[INFO] [stdout]    |
[INFO] [stdout] 26 |   let none = plus_one(None);
[INFO] [stdout]    |       ^^^^ help: if this is intentional, prefix it with an underscore: `_none`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variants `Penny`, `Nickel`, and `Dime` are never constructed
[INFO] [stdout]  --> src/match.rs:2:3
[INFO] [stdout]   |
[INFO] [stdout] 1 | enum Coin {
[INFO] [stdout]   |      ---- variants in this enum
[INFO] [stdout] 2 |   Penny,
[INFO] [stdout]   |   ^^^^^
[INFO] [stdout] 3 |   Nickel,
[INFO] [stdout]   |   ^^^^^^
[INFO] [stdout] 4 |   Dime,
[INFO] [stdout]   |   ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `Alabama` is never constructed
[INFO] [stdout]   --> src/match.rs:10:3
[INFO] [stdout]    |
[INFO] [stdout] 9  | enum UsState {
[INFO] [stdout]    |      ------- variant in this enum
[INFO] [stdout] 10 |   Alabama,
[INFO] [stdout]    |   ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `UsState` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s6`
[INFO] [stdout]   --> src/owner.rs:19:7
[INFO] [stdout]    |
[INFO] [stdout] 19 |   let s6 = s5;
[INFO] [stdout]    |       ^^ help: if this is intentional, prefix it with an underscore: `_s6`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `gives_ownership` is never used
[INFO] [stdout]   --> src/owner.rs:37:4
[INFO] [stdout]    |
[INFO] [stdout] 37 | fn gives_ownership() -> String {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]  --> src/rc.rs:7:10
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons(Rc<RefCell<i32>>, Rc<List>),
[INFO] [stdout]   |     ---- ^^^^^^^^^^^^^^^^  ^^^^^^^^
[INFO] [stdout]   |     |
[INFO] [stdout]   |     fields in this variant
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons((), ()),
[INFO] [stdout]   |          ~~  ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `integer`
[INFO] [stdout]   --> src/generics.rs:14:7
[INFO] [stdout]    |
[INFO] [stdout] 14 |   let integer = Point {
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_integer`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `y` is never read
[INFO] [stdout]  --> src/generics.rs:3:3
[INFO] [stdout]   |
[INFO] [stdout] 1 | struct Point<T> {
[INFO] [stdout]   |        ----- field in this struct
[INFO] [stdout] 2 |   x: T,
[INFO] [stdout] 3 |   y: T
[INFO] [stdout]   |   ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::rc::Rc`
[INFO] [stdout]  --> src/shared_mem.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::rc::Rc;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::rc::Rc`
[INFO] [stdout]  --> src/shared_mem.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::rc::Rc;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused doc comment
[INFO] [stdout]   --> src/struct_ex.rs:17:3
[INFO] [stdout]    |
[INFO] [stdout] 17 |   ///
[INFO] [stdout]    |   ^^^
[INFO] [stdout] 18 |   let rect1 = (30, 50);
[INFO] [stdout]    |   --------------------- rustdoc does not generate documentation for statements
[INFO] [stdout]    |
[INFO] [stdout]    = help: use `//` for a plain comment
[INFO] [stdout]    = note: `#[warn(unused_doc_comments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/slice.rs:2:7
[INFO] [stdout]   |
[INFO] [stdout] 2 |   let mut s = String::from("hello world");
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]  --> src/cycle_ref.rs:7:10
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons(i32, RefCell<Rc<List>>),
[INFO] [stdout]   |     ---- ^^^
[INFO] [stdout]   |     |
[INFO] [stdout]   |     field in this variant
[INFO] [stdout]   |
[INFO] [stdout]   = note: `List` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]   |
[INFO] [stdout] 7 |     Cons((), RefCell<Rc<List>>),
[INFO] [stdout]   |          ~~
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `refcall`
[INFO] [stdout]   --> src/refcall.rs:66:2
[INFO] [stdout]    |
[INFO] [stdout] 66 | }
[INFO] [stdout]    |  ^ consider adding a `main` function to `src/refcall.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/slice.rs:2:7
[INFO] [stdout]   |
[INFO] [stdout] 2 |   let mut s = String::from("hello world");
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust_learning` (bin "refcall") due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]   --> src/enum.rs:20:7
[INFO] [stdout]    |
[INFO] [stdout] 20 |   let six = IpAddrKind::V6;
[INFO] [stdout]    |       ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]   --> src/enum.rs:27:7
[INFO] [stdout]    |
[INFO] [stdout] 27 |   let home = IpAddr {
[INFO] [stdout]    |       ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `op_type`
[INFO] [stdout]   --> src/enum.rs:35:10
[INFO] [stdout]    |
[INFO] [stdout] 35 | fn route(op_type: IpAddrKind) { }
[INFO] [stdout]    |          ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_op_type`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `kind` and `address` are never read
[INFO] [stdout]   --> src/enum.rs:14:3
[INFO] [stdout]    |
[INFO] [stdout] 13 | struct IpAddr {
[INFO] [stdout]    |        ------ fields in this struct
[INFO] [stdout] 14 |   kind: IpAddrKind,
[INFO] [stdout]    |   ^^^^
[INFO] [stdout] 15 |   address: String
[INFO] [stdout]    |   ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "dff51d593e32f1f899f92c316987bf34190b6ebe86e170aaa68e8b201f708909", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dff51d593e32f1f899f92c316987bf34190b6ebe86e170aaa68e8b201f708909", kill_on_drop: false }`
[INFO] [stdout] dff51d593e32f1f899f92c316987bf34190b6ebe86e170aaa68e8b201f708909