[INFO] updating cached repository https://github.com/luzeduardo/rust-exercises
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] [stderr] From https://github.com/luzeduardo/rust-exercises
[INFO] [stderr]    87148be..4e5a430  master     -> master
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 4e5a43020e6c7994b79acb1d65c9675ee654ce1a
[INFO] checking luzeduardo/rust-exercises against try#a243773eaf3fedcd203f10ae4579e4f106bf7ccd for pr-68325
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fluzeduardo%2Frust-exercises" "/workspace/builds/worker-11/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/luzeduardo/rust-exercises on toolchain a243773eaf3fedcd203f10ae4579e4f106bf7ccd
[INFO] running `"/workspace/cargo-home/bin/cargo" "+a243773eaf3fedcd203f10ae4579e4f106bf7ccd" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/luzeduardo/rust-exercises
[INFO] finished tweaking git repo https://github.com/luzeduardo/rust-exercises
[INFO] tweaked toml for git repo https://github.com/luzeduardo/rust-exercises written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate git repo https://github.com/luzeduardo/rust-exercises already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+a243773eaf3fedcd203f10ae4579e4f106bf7ccd" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+a243773eaf3fedcd203f10ae4579e4f106bf7ccd" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 1967c6be366ddbe0771a00c649a0acb77c659527b41b2a13b9d8a6559fa2afe3
[INFO] running `"docker" "start" "-a" "1967c6be366ddbe0771a00c649a0acb77c659527b41b2a13b9d8a6559fa2afe3"`
[INFO] [stderr]     Checking exercises v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/main.rs:45:29
[INFO] [stderr]    |
[INFO] [stderr] 45 |         pub spells: Vec<Box<Cast>>,
[INFO] [stderr]    |                             ^^^^ help: use `dyn`: `dyn Cast`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/main.rs:45:29
[INFO] [stderr]    |
[INFO] [stderr] 45 |         pub spells: Vec<Box<Cast>>,
[INFO] [stderr]    |                             ^^^^ help: use `dyn`: `dyn Cast`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `character`
[INFO] [stderr]    --> src/main.rs:141:36
[INFO] [stderr]     |
[INFO] [stderr] 141 |     pub fn speak_elvish<T: Elvish>(character: T) -> String {
[INFO] [stderr]     |                                    ^^^^^^^^^ help: consider prefixing with an underscore: `_character`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `character`
[INFO] [stderr]    --> src/main.rs:141:36
[INFO] [stderr]     |
[INFO] [stderr] 141 |     pub fn speak_elvish<T: Elvish>(character: T) -> String {
[INFO] [stderr]     |                                    ^^^^^^^^^ help: consider prefixing with an underscore: `_character`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `len`
[INFO] [stderr]    --> src/main.rs:252:9
[INFO] [stderr]     |
[INFO] [stderr] 252 |     let len = String::from("Hola").len();
[INFO] [stderr]     |         ^^^ help: consider prefixing with an underscore: `_len`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `a`
[INFO] [stderr]    --> src/main.rs:256:13
[INFO] [stderr]     |
[INFO] [stderr] 256 |     let mut a = String::new();
[INFO] [stderr]     |             ^ help: consider prefixing with an underscore: `_a`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `len`
[INFO] [stderr]    --> src/main.rs:252:9
[INFO] [stderr]     |
[INFO] [stderr] 252 |     let len = String::from("Hola").len();
[INFO] [stderr]     |         ^^^ help: consider prefixing with an underscore: `_len`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `a`
[INFO] [stderr]    --> src/main.rs:256:13
[INFO] [stderr]     |
[INFO] [stderr] 256 |     let mut a = String::new();
[INFO] [stderr]     |             ^ help: consider prefixing with an underscore: `_a`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s1`
[INFO] [stderr]    --> src/main.rs:261:9
[INFO] [stderr]     |
[INFO] [stderr] 261 |     let s1 = String::from("raise error if access by index");
[INFO] [stderr]     |         ^^ help: consider prefixing with an underscore: `_s1`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s1`
[INFO] [stderr]    --> src/main.rs:261:9
[INFO] [stderr]     |
[INFO] [stderr] 261 |     let s1 = String::from("raise error if access by index");
[INFO] [stderr]     |         ^^ help: consider prefixing with an underscore: `_s1`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `integer`
[INFO] [stderr]    --> src/main.rs:408:9
[INFO] [stderr]     |
[INFO] [stderr] 408 |     let integer = Point { x: 1, y:2 };
[INFO] [stderr]     |         ^^^^^^^ help: consider prefixing with an underscore: `_integer`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `float`
[INFO] [stderr]    --> src/main.rs:409:9
[INFO] [stderr]     |
[INFO] [stderr] 409 |     let float = Point { x: 1.0, y: 2.1 };
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_float`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `integer_float`
[INFO] [stderr]    --> src/main.rs:415:9
[INFO] [stderr]     |
[INFO] [stderr] 415 |     let integer_float = AreaGenerics { x: 1, y :4.5 };
[INFO] [stderr]     |         ^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_integer_float`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `integer`
[INFO] [stderr]    --> src/main.rs:408:9
[INFO] [stderr]     |
[INFO] [stderr] 408 |     let integer = Point { x: 1, y:2 };
[INFO] [stderr]     |         ^^^^^^^ help: consider prefixing with an underscore: `_integer`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `float`
[INFO] [stderr]    --> src/main.rs:409:9
[INFO] [stderr]     |
[INFO] [stderr] 409 |     let float = Point { x: 1.0, y: 2.1 };
[INFO] [stderr]     |         ^^^^^ help: consider prefixing with an underscore: `_float`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `integer_float`
[INFO] [stderr]    --> src/main.rs:415:9
[INFO] [stderr]     |
[INFO] [stderr] 415 |     let integer_float = AreaGenerics { x: 1, y :4.5 };
[INFO] [stderr]     |         ^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_integer_float`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:256:9
[INFO] [stderr]     |
[INFO] [stderr] 256 |     let mut a = String::new();
[INFO] [stderr]     |         ----^
[INFO] [stderr]     |         |
[INFO] [stderr]     |         help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:256:9
[INFO] [stderr]     |
[INFO] [stderr] 256 |     let mut a = String::new();
[INFO] [stderr]     |         ----^
[INFO] [stderr]     |         |
[INFO] [stderr]     |         help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_traits`
[INFO] [stderr]    --> src/main.rs:111:4
[INFO] [stderr]     |
[INFO] [stderr] 111 | fn testing_traits() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_hash_map`
[INFO] [stderr]    --> src/main.rs:205:4
[INFO] [stderr]     |
[INFO] [stderr] 205 | fn testing_hash_map() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_internal_representation_of_string`
[INFO] [stderr]    --> src/main.rs:251:4
[INFO] [stderr]     |
[INFO] [stderr] 251 | fn testing_internal_representation_of_string() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_traits`
[INFO] [stderr]    --> src/main.rs:111:4
[INFO] [stderr]     |
[INFO] [stderr] 111 | fn testing_traits() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_strings`
[INFO] [stderr]    --> src/main.rs:255:4
[INFO] [stderr]     |
[INFO] [stderr] 255 | fn testing_strings() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_hash_map`
[INFO] [stderr]    --> src/main.rs:205:4
[INFO] [stderr]     |
[INFO] [stderr] 205 | fn testing_hash_map() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_vector`
[INFO] [stderr]    --> src/main.rs:276:4
[INFO] [stderr]     |
[INFO] [stderr] 276 | fn testing_vector() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_internal_representation_of_string`
[INFO] [stderr]    --> src/main.rs:251:4
[INFO] [stderr]     |
[INFO] [stderr] 251 | fn testing_internal_representation_of_string() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_refactoring_struct_tuples`
[INFO] [stderr]    --> src/main.rs:318:4
[INFO] [stderr]     |
[INFO] [stderr] 318 | fn testing_refactoring_struct_tuples() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_strings`
[INFO] [stderr]    --> src/main.rs:255:4
[INFO] [stderr]     |
[INFO] [stderr] 255 | fn testing_strings() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `area`
[INFO] [stderr]    --> src/main.rs:336:5
[INFO] [stderr]     |
[INFO] [stderr] 336 |     fn area(&self) -> u32 {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `square`
[INFO] [stderr]    --> src/main.rs:343:5
[INFO] [stderr]     |
[INFO] [stderr] 343 |     fn square(size: u32) -> Rectangle {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_dangle_error`
[INFO] [stderr]    --> src/main.rs:351:4
[INFO] [stderr]     |
[INFO] [stderr] 351 | fn testing_dangle_error() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_vector`
[INFO] [stderr]    --> src/main.rs:276:4
[INFO] [stderr]     |
[INFO] [stderr] 276 | fn testing_vector() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `dangle_error`
[INFO] [stderr]    --> src/main.rs:356:4
[INFO] [stderr]     |
[INFO] [stderr] 356 | fn dangle_error() -> String {
[INFO] [stderr]     |    ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_refactoring_struct_tuples`
[INFO] [stderr]    --> src/main.rs:318:4
[INFO] [stderr]     |
[INFO] [stderr] 318 | fn testing_refactoring_struct_tuples() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `area`
[INFO] [stderr]    --> src/main.rs:365:4
[INFO] [stderr]     |
[INFO] [stderr] 365 | fn area(rectangle: &Rectangle) -> u32 {
[INFO] [stderr]     |    ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `area`
[INFO] [stderr]    --> src/main.rs:336:5
[INFO] [stderr]     |
[INFO] [stderr] 336 |     fn area(&self) -> u32 {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_takes_ownership`
[INFO] [stderr]    --> src/main.rs:369:4
[INFO] [stderr]     |
[INFO] [stderr] 369 | fn testing_takes_ownership() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `square`
[INFO] [stderr]    --> src/main.rs:343:5
[INFO] [stderr]     |
[INFO] [stderr] 343 |     fn square(size: u32) -> Rectangle {
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_ownership`
[INFO] [stderr]    --> src/main.rs:379:4
[INFO] [stderr]     |
[INFO] [stderr] 379 | fn takes_ownership(somestring: String) {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_dangle_error`
[INFO] [stderr]    --> src/main.rs:351:4
[INFO] [stderr]     |
[INFO] [stderr] 351 | fn testing_dangle_error() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `makes_copy`
[INFO] [stderr]    --> src/main.rs:382:4
[INFO] [stderr]     |
[INFO] [stderr] 382 | fn makes_copy(example_integer: u32) {
[INFO] [stderr]     |    ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `dangle_error`
[INFO] [stderr]    --> src/main.rs:356:4
[INFO] [stderr]     |
[INFO] [stderr] 356 | fn dangle_error() -> String {
[INFO] [stderr]     |    ^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_owner_refs`
[INFO] [stderr]    --> src/main.rs:386:4
[INFO] [stderr]     |
[INFO] [stderr] 386 | fn testing_owner_refs() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_structs`
[INFO] [stderr]    --> src/main.rs:403:4
[INFO] [stderr]     |
[INFO] [stderr] 403 | fn testing_structs() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `first_word`
[INFO] [stderr]    --> src/main.rs:435:4
[INFO] [stderr]     |
[INFO] [stderr] 435 | fn first_word(s: &str) -> &str {
[INFO] [stderr]     |    ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `area`
[INFO] [stderr]    --> src/main.rs:365:4
[INFO] [stderr]     |
[INFO] [stderr] 365 | fn area(rectangle: &Rectangle) -> u32 {
[INFO] [stderr]     |    ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `change`
[INFO] [stderr]    --> src/main.rs:446:4
[INFO] [stderr]     |
[INFO] [stderr] 446 | fn change(s: &mut String) {
[INFO] [stderr]     |    ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_takes_ownership`
[INFO] [stderr]    --> src/main.rs:369:4
[INFO] [stderr]     |
[INFO] [stderr] 369 | fn testing_takes_ownership() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `calculate_length_with_reference`
[INFO] [stderr]    --> src/main.rs:450:4
[INFO] [stderr]     |
[INFO] [stderr] 450 | fn calculate_length_with_reference(s: &String) -> usize {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_ownership`
[INFO] [stderr]    --> src/main.rs:379:4
[INFO] [stderr]     |
[INFO] [stderr] 379 | fn takes_ownership(somestring: String) {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `makes_copy`
[INFO] [stderr]    --> src/main.rs:382:4
[INFO] [stderr]     |
[INFO] [stderr] 382 | fn makes_copy(example_integer: u32) {
[INFO] [stderr]     |    ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_owner_refs`
[INFO] [stderr]    --> src/main.rs:386:4
[INFO] [stderr]     |
[INFO] [stderr] 386 | fn testing_owner_refs() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `testing_structs`
[INFO] [stderr]    --> src/main.rs:403:4
[INFO] [stderr]     |
[INFO] [stderr] 403 | fn testing_structs() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `first_word`
[INFO] [stderr]    --> src/main.rs:435:4
[INFO] [stderr]     |
[INFO] [stderr] 435 | fn first_word(s: &str) -> &str {
[INFO] [stderr]     |    ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `change`
[INFO] [stderr]    --> src/main.rs:446:4
[INFO] [stderr]     |
[INFO] [stderr] 446 | fn change(s: &mut String) {
[INFO] [stderr]     |    ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `calculate_length_with_reference`
[INFO] [stderr]    --> src/main.rs:450:4
[INFO] [stderr]     |
[INFO] [stderr] 450 | fn calculate_length_with_reference(s: &String) -> usize {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `gives_ownership`
[INFO] [stderr]    --> src/main.rs:454:4
[INFO] [stderr]     |
[INFO] [stderr] 454 | fn gives_ownership() -> String {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_and_gives_back_ownership`
[INFO] [stderr]    --> src/main.rs:459:4
[INFO] [stderr]     |
[INFO] [stderr] 459 | fn takes_and_gives_back_ownership(a_string: String) -> String {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `gives_ownership`
[INFO] [stderr]    --> src/main.rs:454:4
[INFO] [stderr]     |
[INFO] [stderr] 454 | fn gives_ownership() -> String {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `takes_and_gives_back_ownership`
[INFO] [stderr]    --> src/main.rs:459:4
[INFO] [stderr]     |
[INFO] [stderr] 459 | fn takes_and_gives_back_ownership(a_string: String) -> String {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.66s
[INFO] running `"docker" "inspect" "1967c6be366ddbe0771a00c649a0acb77c659527b41b2a13b9d8a6559fa2afe3"`
[INFO] running `"docker" "rm" "-f" "1967c6be366ddbe0771a00c649a0acb77c659527b41b2a13b9d8a6559fa2afe3"`
[INFO] [stdout] 1967c6be366ddbe0771a00c649a0acb77c659527b41b2a13b9d8a6559fa2afe3