[INFO] cloning repository https://github.com/sobersanta/hello-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sobersanta/hello-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsobersanta%2Fhello-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsobersanta%2Fhello-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b869da0928681b3e833519615cdad4cdfc11f377
[INFO] testing sobersanta/hello-rust against 1.59.0 for beta-1.60-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsobersanta%2Fhello-rust" "/workspace/builds/worker-50/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-50/source'...
[INFO] [stderr] done.
[INFO] [stderr] Updating files:  24% (6/25)
Updating files:  28% (7/25)
Updating files:  32% (8/25)
Updating files:  36% (9/25)
Updating files:  40% (10/25)
Updating files:  44% (11/25)
Updating files:  48% (12/25)
Updating files:  52% (13/25)
Updating files:  56% (14/25)
Updating files:  60% (15/25)
Updating files:  64% (16/25)
Updating files:  68% (17/25)
Updating files:  72% (18/25)
Updating files:  76% (19/25)
Updating files:  80% (20/25)
Updating files:  84% (21/25)
Updating files:  88% (22/25)
Updating files:  92% (23/25)
Updating files:  96% (24/25)
Updating files: 100% (25/25)
Updating files: 100% (25/25), done.
[INFO] validating manifest of git repo https://github.com/sobersanta/hello-rust on toolchain 1.59.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sobersanta/hello-rust
[INFO] finished tweaking git repo https://github.com/sobersanta/hello-rust
[INFO] tweaked toml for git repo https://github.com/sobersanta/hello-rust written to /workspace/builds/worker-50/source/Cargo.toml
[INFO] crate git repo https://github.com/sobersanta/hello-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-50/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-50/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 2b5dee8086db18c42d056ce2a96e653cf1cbf669a376cba69ce45a5486bf0c66
[INFO] running `Command { std: "docker" "start" "-a" "2b5dee8086db18c42d056ce2a96e653cf1cbf669a376cba69ce45a5486bf0c66", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2b5dee8086db18c42d056ce2a96e653cf1cbf669a376cba69ce45a5486bf0c66", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2b5dee8086db18c42d056ce2a96e653cf1cbf669a376cba69ce45a5486bf0c66", kill_on_drop: false }`
[INFO] [stdout] 2b5dee8086db18c42d056ce2a96e653cf1cbf669a376cba69ce45a5486bf0c66
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-50/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-50/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f7274ae64d1c419286c17431e78d3fd9b62db86a7e6bc2f28309cdebecf0cad8
[INFO] running `Command { std: "docker" "start" "-a" "f7274ae64d1c419286c17431e78d3fd9b62db86a7e6bc2f28309cdebecf0cad8", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling syn v1.0.58
[INFO] [stderr]    Compiling proc-macro-hack v0.5.19
[INFO] [stderr]    Compiling proc-macro-nested v0.1.6
[INFO] [stderr]    Compiling memchr v2.3.4
[INFO] [stderr]    Compiling futures-sink v0.3.8
[INFO] [stderr]    Compiling futures-core v0.3.8
[INFO] [stderr]    Compiling once_cell v1.5.2
[INFO] [stderr]    Compiling futures-io v0.3.8
[INFO] [stderr]    Compiling pin-utils v0.1.0
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]    Compiling futures-task v0.3.8
[INFO] [stderr]    Compiling futures-channel v0.3.8
[INFO] [stderr]    Compiling pin-project-internal v1.0.3
[INFO] [stderr]    Compiling futures-macro v0.3.8
[INFO] [stderr]    Compiling pin-project v1.0.3
[INFO] [stderr]    Compiling futures-util v0.3.8
[INFO] [stderr]    Compiling futures-executor v0.3.8
[INFO] [stderr]    Compiling futures v0.3.8
[INFO] [stderr]    Compiling hello-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `calculation`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     calculation: T,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `values`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 |     values: HashMap<V, R>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:21:8
[INFO] [stdout]    |
[INFO] [stdout] 21 |     fn new(calculation: T) -> Cacher<T, V, R> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `value`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:28:8
[INFO] [stdout]    |
[INFO] [stdout] 28 |     fn value(&mut self, arg: &V) -> &R {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Solution`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:11:8
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct Solution;
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:34:8
[INFO] [stdout]    |
[INFO] [stdout] 34 |     fn new(x: i32, y: i32) -> Point {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `plus`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:38:8
[INFO] [stdout]    |
[INFO] [stdout] 38 |     fn plus(&mut self, other: &Point) {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `rotate_90_cw`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:43:8
[INFO] [stdout]    |
[INFO] [stdout] 43 |     fn rotate_90_cw(&mut self) {
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `rotate_90_ccw`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:50:8
[INFO] [stdout]    |
[INFO] [stdout] 50 |     fn rotate_90_ccw(&mut self) {
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant is never used: `NORTH`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:58:1
[INFO] [stdout]    |
[INFO] [stdout] 58 | const NORTH: Point = Point { x: 0, y: 1 };
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant is never used: `ZERO`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:59:1
[INFO] [stdout]    |
[INFO] [stdout] 59 | const ZERO: Point = Point { x: 0, y: 0 };
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `is_robot_bounded`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:62:12
[INFO] [stdout]    |
[INFO] [stdout] 62 |     pub fn is_robot_bounded(instructions: String) -> bool {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Solution`
[INFO] [stdout]  --> src/exercises/increasing_subsequences.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct Solution {}
[INFO] [stdout]   |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `find_subsequences`
[INFO] [stdout]  --> src/exercises/increasing_subsequences.rs:7:12
[INFO] [stdout]   |
[INFO] [stdout] 7 |     pub fn find_subsequences(nums: Vec<i32>) -> Vec<Vec<i32>> {
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `recur`
[INFO] [stdout]   --> src/exercises/increasing_subsequences.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn recur(nums: &[i32], last: i32, accum: &mut Vec<i32>, results: &mut HashSet<Vec<i32>>) {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `x`
[INFO] [stdout]  --> src/exercises/borrow_xxx/mod.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 |     x: String,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `y`
[INFO] [stdout]  --> src/exercises/borrow_xxx/mod.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     y: String,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_a_mut`
[INFO] [stdout]  --> src/exercises/borrow_xxx/mod.rs:8:8
[INFO] [stdout]   |
[INFO] [stdout] 8 |     fn get_a_mut(self: &mut A) -> &'_ mut String {
[INFO] [stdout]   |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 18 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 16.30s
[INFO] running `Command { std: "docker" "inspect" "f7274ae64d1c419286c17431e78d3fd9b62db86a7e6bc2f28309cdebecf0cad8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f7274ae64d1c419286c17431e78d3fd9b62db86a7e6bc2f28309cdebecf0cad8", kill_on_drop: false }`
[INFO] [stdout] f7274ae64d1c419286c17431e78d3fd9b62db86a7e6bc2f28309cdebecf0cad8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-50/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-50/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@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 086a0fb035570ef5ed2948acd44301e0bcc9380de7eb55ea93b50e6c1cb56e7c
[INFO] running `Command { std: "docker" "start" "-a" "086a0fb035570ef5ed2948acd44301e0bcc9380de7eb55ea93b50e6c1cb56e7c", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stdout] warning: field is never read: `calculation`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 |     calculation: T,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `values`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:12:5
[INFO] [stdout]    |
[INFO] [stdout] 12 |     values: HashMap<V, R>,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:21:8
[INFO] [stdout]    |
[INFO] [stdout] 21 |     fn new(calculation: T) -> Cacher<T, V, R> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `value`
[INFO] [stdout]   --> src/exercises/cacher/mod.rs:28:8
[INFO] [stdout]    |
[INFO] [stdout] 28 |     fn value(&mut self, arg: &V) -> &R {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Solution`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:11:8
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct Solution;
[INFO] [stdout]    |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:34:8
[INFO] [stdout]    |
[INFO] [stdout] 34 |     fn new(x: i32, y: i32) -> Point {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `plus`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:38:8
[INFO] [stdout]    |
[INFO] [stdout] 38 |     fn plus(&mut self, other: &Point) {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `rotate_90_cw`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:43:8
[INFO] [stdout]    |
[INFO] [stdout] 43 |     fn rotate_90_cw(&mut self) {
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `rotate_90_ccw`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:50:8
[INFO] [stdout]    |
[INFO] [stdout] 50 |     fn rotate_90_ccw(&mut self) {
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant is never used: `NORTH`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:58:1
[INFO] [stdout]    |
[INFO] [stdout] 58 | const NORTH: Point = Point { x: 0, y: 1 };
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant is never used: `ZERO`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:59:1
[INFO] [stdout]    |
[INFO] [stdout] 59 | const ZERO: Point = Point { x: 0, y: 0 };
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `is_robot_bounded`
[INFO] [stdout]   --> src/exercises/is_robot_bounded.rs:62:12
[INFO] [stdout]    |
[INFO] [stdout] 62 |     pub fn is_robot_bounded(instructions: String) -> bool {
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `Solution`
[INFO] [stdout]  --> src/exercises/increasing_subsequences.rs:4:8
[INFO] [stdout]   |
[INFO] [stdout] 4 | struct Solution {}
[INFO] [stdout]   |        ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `find_subsequences`
[INFO] [stdout]  --> src/exercises/increasing_subsequences.rs:7:12
[INFO] [stdout]   |
[INFO] [stdout] 7 |     pub fn find_subsequences(nums: Vec<i32>) -> Vec<Vec<i32>> {
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `recur`
[INFO] [stdout]   --> src/exercises/increasing_subsequences.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn recur(nums: &[i32], last: i32, accum: &mut Vec<i32>, results: &mut HashSet<Vec<i32>>) {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field is never read: `x`
[INFO] [stdout]  --> src/exercises/borrow_xxx/mod.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 |     x: String,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling hello-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: field is never read: `y`
[INFO] [stdout]  --> src/exercises/borrow_xxx/mod.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     y: String,
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `get_a_mut`
[INFO] [stdout]  --> src/exercises/borrow_xxx/mod.rs:8:8
[INFO] [stdout]   |
[INFO] [stdout] 8 |     fn get_a_mut(self: &mut A) -> &'_ mut String {
[INFO] [stdout]   |        ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 18 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `a` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/exercises/borrow_xxx/mod.rs:36:9
[INFO] [stdout]    |
[INFO] [stdout] 35 |         let y = &a.y;
[INFO] [stdout]    |                 ---- immutable borrow occurs here
[INFO] [stdout] 36 |         a.get_a_mut().xxx(|| String::from(y));
[INFO] [stdout]    |         ^^^^^^^^^^^^^                     - immutable borrow later captured here by closure
[INFO] [stdout]    |         |
[INFO] [stdout]    |         mutable borrow occurs here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0502`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `hello-rust` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "086a0fb035570ef5ed2948acd44301e0bcc9380de7eb55ea93b50e6c1cb56e7c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "086a0fb035570ef5ed2948acd44301e0bcc9380de7eb55ea93b50e6c1cb56e7c", kill_on_drop: false }`
[INFO] [stdout] 086a0fb035570ef5ed2948acd44301e0bcc9380de7eb55ea93b50e6c1cb56e7c