[INFO] cloning repository https://github.com/jarinosuke/rust-programming-introduction
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/jarinosuke/rust-programming-introduction" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjarinosuke%2Frust-programming-introduction", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjarinosuke%2Frust-programming-introduction'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] a013f7630da2ea03e08f82170533efba530b3b62
[INFO] checking jarinosuke/rust-programming-introduction against master#6526e5c772f2da07db745c94ca6bb0a591a39ba4 for pr-80920
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjarinosuke%2Frust-programming-introduction" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/jarinosuke/rust-programming-introduction on toolchain 6526e5c772f2da07db745c94ca6bb0a591a39ba4
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/jarinosuke/rust-programming-introduction
[INFO] finished tweaking git repo https://github.com/jarinosuke/rust-programming-introduction
[INFO] tweaked toml for git repo https://github.com/jarinosuke/rust-programming-introduction written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/jarinosuke/rust-programming-introduction already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] eb483a71ba669d074c9df26c7a9d356c069618e8943d9918c5e61c9630b02a6f
[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" "eb483a71ba669d074c9df26c7a9d356c069618e8943d9918c5e61c9630b02a6f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "eb483a71ba669d074c9df26c7a9d356c069618e8943d9918c5e61c9630b02a6f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "eb483a71ba669d074c9df26c7a9d356c069618e8943d9918c5e61c9630b02a6f", kill_on_drop: false }`
[INFO] [stdout] eb483a71ba669d074c9df26c7a9d356c069618e8943d9918c5e61c9630b02a6f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+6526e5c772f2da07db745c94ca6bb0a591a39ba4" "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] 8c0eb5e35ef339fa852539ef1f092c957ceb6f7ab5807218433b438bea8f7afa
[INFO] running `Command { std: "docker" "start" "-a" "8c0eb5e35ef339fa852539ef1f092c957ceb6f7ab5807218433b438bea8f7afa", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.58
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]     Checking futures-core v0.3.9
[INFO] [stderr]     Checking futures-sink v0.3.9
[INFO] [stderr]     Checking futures-io v0.3.9
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]     Checking pin-project-lite v0.1.11
[INFO] [stderr]     Checking bytes v0.5.6
[INFO] [stderr]     Checking futures-task v0.3.9
[INFO] [stderr]     Checking futures-channel v0.3.9
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]    Compiling futures-macro v0.3.9
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]    Compiling async-trait v0.1.42
[INFO] [stderr]     Checking tokio v0.2.24
[INFO] [stderr]     Checking futures-util v0.3.9
[INFO] [stderr]     Checking futures-executor v0.3.9
[INFO] [stderr]     Checking futures v0.3.9
[INFO] [stderr]     Checking rust-programming-introduction v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused label
[INFO] [stdout]    --> src/main.rs:118:9
[INFO] [stdout]     |
[INFO] [stdout] 118 |         'sub: loop {
[INFO] [stdout]     |         ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_labels)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]    --> src/main.rs:118:9
[INFO] [stdout]     |
[INFO] [stdout] 118 |         'sub: loop {
[INFO] [stdout]     |         ^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_labels)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s3`
[INFO] [stdout]   --> src/main.rs:15:12
[INFO] [stdout]    |
[INFO] [stdout] 15 |        let s3: String = s2.to_string();
[INFO] [stdout]    |            ^^ help: if this is intentional, prefix it with an underscore: `_s3`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p`
[INFO] [stdout]   --> src/main.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let p = Person {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_p`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `e1`
[INFO] [stdout]   --> src/main.rs:38:9
[INFO] [stdout]    |
[INFO] [stdout] 38 |     let e1 = Event::Quit;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_e1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `e2`
[INFO] [stdout]   --> src/main.rs:39:9
[INFO] [stdout]    |
[INFO] [stdout] 39 |     let e2 = Event::MouseDown { x: 10, y: 10 };
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_e2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `next_result3`
[INFO] [stdout]   --> src/main.rs:56:9
[INFO] [stdout]    |
[INFO] [stdout] 56 |     let next_result3 = result3.and_then(func);
[INFO] [stdout]    |         ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_next_result3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `next_result4`
[INFO] [stdout]   --> src/main.rs:58:9
[INFO] [stdout]    |
[INFO] [stdout] 58 |     let next_result4 = result4.and_then(func);
[INFO] [stdout]    |         ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_next_result4`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v2`
[INFO] [stdout]   --> src/main.rs:62:9
[INFO] [stdout]    |
[INFO] [stdout] 62 |     let v2 = vec![0; 5];
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_v2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]   --> src/main.rs:82:9
[INFO] [stdout]    |
[INFO] [stdout] 82 |     let result = if 0 <= number2 {
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result2`
[INFO] [stdout]   --> src/main.rs:90:9
[INFO] [stdout]    |
[INFO] [stdout] 90 |     let result2 = loop {
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_result2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `count3`
[INFO] [stdout]    --> src/main.rs:106:9
[INFO] [stdout]     |
[INFO] [stdout] 106 |     let count3 = 0;
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_count3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result_number`
[INFO] [stdout]    --> src/main.rs:141:9
[INFO] [stdout]     |
[INFO] [stdout] 141 |     let result_number = match result5 {
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_result_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s3`
[INFO] [stdout]   --> src/main.rs:15:12
[INFO] [stdout]    |
[INFO] [stdout] 15 |        let s3: String = s2.to_string();
[INFO] [stdout]    |            ^^ help: if this is intentional, prefix it with an underscore: `_s3`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p`
[INFO] [stdout]   --> src/main.rs:32:9
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let p = Person {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_p`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `e1`
[INFO] [stdout]   --> src/main.rs:38:9
[INFO] [stdout]    |
[INFO] [stdout] 38 |     let e1 = Event::Quit;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_e1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `e2`
[INFO] [stdout]   --> src/main.rs:39:9
[INFO] [stdout]    |
[INFO] [stdout] 39 |     let e2 = Event::MouseDown { x: 10, y: 10 };
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_e2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `next_result3`
[INFO] [stdout]   --> src/main.rs:56:9
[INFO] [stdout]    |
[INFO] [stdout] 56 |     let next_result3 = result3.and_then(func);
[INFO] [stdout]    |         ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_next_result3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `next_result4`
[INFO] [stdout]   --> src/main.rs:58:9
[INFO] [stdout]    |
[INFO] [stdout] 58 |     let next_result4 = result4.and_then(func);
[INFO] [stdout]    |         ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_next_result4`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v2`
[INFO] [stdout]   --> src/main.rs:62:9
[INFO] [stdout]    |
[INFO] [stdout] 62 |     let v2 = vec![0; 5];
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_v2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]   --> src/main.rs:82:9
[INFO] [stdout]    |
[INFO] [stdout] 82 |     let result = if 0 <= number2 {
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result2`
[INFO] [stdout]   --> src/main.rs:90:9
[INFO] [stdout]    |
[INFO] [stdout] 90 |     let result2 = loop {
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_result2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `count3`
[INFO] [stdout]    --> src/main.rs:106:9
[INFO] [stdout]     |
[INFO] [stdout] 106 |     let count3 = 0;
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_count3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result_number`
[INFO] [stdout]    --> src/main.rs:141:9
[INFO] [stdout]     |
[INFO] [stdout] 141 |     let result_number = match result5 {
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_result_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `error_handling`
[INFO] [stdout]    --> src/main.rs:196:4
[INFO] [stdout]     |
[INFO] [stdout] 196 | fn error_handling(result: Result<i32, String>) -> Result<i32, String> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]    --> src/main.rs:211:8
[INFO] [stdout]     |
[INFO] [stdout] 211 |     fn new(name: &str, age: u32) -> Person {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `KeyDown`
[INFO] [stdout]    --> src/main.rs:231:5
[INFO] [stdout]     |
[INFO] [stdout] 231 |     KeyDown(u8),
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `x`
[INFO] [stdout]    --> src/main.rs:232:17
[INFO] [stdout]     |
[INFO] [stdout] 232 |     MouseDown { x: i32, y: i32 },
[INFO] [stdout]     |                 ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `y`
[INFO] [stdout]    --> src/main.rs:232:25
[INFO] [stdout]     |
[INFO] [stdout] 232 |     MouseDown { x: i32, y: i32 },
[INFO] [stdout]     |                         ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Blue`
[INFO] [stdout]    --> src/main.rs:237:5
[INFO] [stdout]     |
[INFO] [stdout] 237 |     Blue,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Green`
[INFO] [stdout]    --> src/main.rs:238:5
[INFO] [stdout]     |
[INFO] [stdout] 238 |     Green,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `something_great_async_function2`
[INFO] [stdout]    --> src/main.rs:289:4
[INFO] [stdout]     |
[INFO] [stdout] 289 | fn something_great_async_function2() -> impl Future<Output = i32> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `move_to_async_block`
[INFO] [stdout]    --> src/main.rs:297:4
[INFO] [stdout]     |
[INFO] [stdout] 297 | fn move_to_async_block() -> impl Future<Output = ()> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `error_handling`
[INFO] [stdout]    --> src/main.rs:196:4
[INFO] [stdout]     |
[INFO] [stdout] 196 | fn error_handling(result: Result<i32, String>) -> Result<i32, String> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]    --> src/main.rs:211:8
[INFO] [stdout]     |
[INFO] [stdout] 211 |     fn new(name: &str, age: u32) -> Person {
[INFO] [stdout]     |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `KeyDown`
[INFO] [stdout]    --> src/main.rs:231:5
[INFO] [stdout]     |
[INFO] [stdout] 231 |     KeyDown(u8),
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `x`
[INFO] [stdout]    --> src/main.rs:232:17
[INFO] [stdout]     |
[INFO] [stdout] 232 |     MouseDown { x: i32, y: i32 },
[INFO] [stdout]     |                 ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `y`
[INFO] [stdout]    --> src/main.rs:232:25
[INFO] [stdout]     |
[INFO] [stdout] 232 |     MouseDown { x: i32, y: i32 },
[INFO] [stdout]     |                         ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Blue`
[INFO] [stdout]    --> src/main.rs:237:5
[INFO] [stdout]     |
[INFO] [stdout] 237 |     Blue,
[INFO] [stdout]     |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Green`
[INFO] [stdout]    --> src/main.rs:238:5
[INFO] [stdout]     |
[INFO] [stdout] 238 |     Green,
[INFO] [stdout]     |     ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `something_great_async_function2`
[INFO] [stdout]    --> src/main.rs:289:4
[INFO] [stdout]     |
[INFO] [stdout] 289 | fn something_great_async_function2() -> impl Future<Output = i32> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `move_to_async_block`
[INFO] [stdout]    --> src/main.rs:297:4
[INFO] [stdout]     |
[INFO] [stdout] 297 | fn move_to_async_block() -> impl Future<Output = ()> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:175:5
[INFO] [stdout]     |
[INFO] [stdout] 175 |     write!(&mut w, "{}", "ABC");
[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 a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:176:5
[INFO] [stdout]     |
[INFO] [stdout] 176 |     writeln!(&mut w, " is 123");
[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 a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 23 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:175:5
[INFO] [stdout]     |
[INFO] [stdout] 175 |     write!(&mut w, "{}", "ABC");
[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 a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/main.rs:176:5
[INFO] [stdout]     |
[INFO] [stdout] 176 |     writeln!(&mut w, " is 123");
[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 a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 23 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 35.03s
[INFO] running `Command { std: "docker" "inspect" "8c0eb5e35ef339fa852539ef1f092c957ceb6f7ab5807218433b438bea8f7afa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8c0eb5e35ef339fa852539ef1f092c957ceb6f7ab5807218433b438bea8f7afa", kill_on_drop: false }`
[INFO] [stdout] 8c0eb5e35ef339fa852539ef1f092c957ceb6f7ab5807218433b438bea8f7afa