[INFO] updating cached repository https://github.com/suhanyujie/hello_cargo
[INFO] running `Command { std: "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", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ad8b723b1eb53e56c14c0ac7a919be70b4190353
[INFO] testing suhanyujie/hello_cargo against beta-2020-07-24 for beta-1.46-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsuhanyujie%2Fhello_cargo" "/workspace/builds/worker-11/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/suhanyujie/hello_cargo on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/suhanyujie/hello_cargo
[INFO] finished tweaking git repo https://github.com/suhanyujie/hello_cargo
[INFO] tweaked toml for git repo https://github.com/suhanyujie/hello_cargo written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate git repo https://github.com/suhanyujie/hello_cargo already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "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_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e450f2fe7b0ee2281b8f4995640f42d65f67f8a3b96f6a1a7ac454377b186275
[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" "e450f2fe7b0ee2281b8f4995640f42d65f67f8a3b96f6a1a7ac454377b186275", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e450f2fe7b0ee2281b8f4995640f42d65f67f8a3b96f6a1a7ac454377b186275", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e450f2fe7b0ee2281b8f4995640f42d65f67f8a3b96f6a1a7ac454377b186275", kill_on_drop: false }`
[INFO] [stdout] e450f2fe7b0ee2281b8f4995640f42d65f67f8a3b96f6a1a7ac454377b186275
[INFO] running `Command { std: "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=warn" "-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@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 34aacc02dba01c591ad38a27b27c1b280f2b40ca6360c3ced9344d35ef95d449
[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" "34aacc02dba01c591ad38a27b27c1b280f2b40ca6360c3ced9344d35ef95d449", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v0.4.25
[INFO] [stderr]    Compiling encode_unicode v0.3.5
[INFO] [stderr]    Compiling term v0.5.1
[INFO] [stderr]    Compiling bincode v1.0.1
[INFO] [stderr]    Compiling memchr v2.1.2
[INFO] [stderr]    Compiling atty v0.2.11
[INFO] [stderr]    Compiling rand v0.4.5
[INFO] [stderr]    Compiling clap v2.32.0
[INFO] [stderr]    Compiling csv-core v0.1.5
[INFO] [stderr]    Compiling csv v1.0.5
[INFO] [stderr]    Compiling rand v0.3.22
[INFO] [stderr]    Compiling quote v0.6.10
[INFO] [stderr]    Compiling syn v0.15.26
[INFO] [stderr]    Compiling prettytable-rs v0.8.0
[INFO] [stderr]    Compiling structopt-derive v0.2.14
[INFO] [stderr]    Compiling serde_derive v1.0.84
[INFO] [stderr]    Compiling structopt v0.2.14
[INFO] [stderr]    Compiling hello_cargo v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `word1`
[INFO] [stdout]   --> src/main.rs:59:9
[INFO] [stdout]    |
[INFO] [stdout] 59 |     let word1 = &my_str1[..];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_word1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/main.rs:57:15
[INFO] [stdout]    |
[INFO] [stdout] 57 | fn slice_show(s: &str) {
[INFO] [stdout]    |               ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `User`
[INFO] [stdout]   --> src/main.rs:14:8
[INFO] [stdout]    |
[INFO] [stdout] 14 | struct User {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum is never used: `Message`
[INFO] [stdout]   --> src/main.rs:20:6
[INFO] [stdout]    |
[INFO] [stdout] 20 | enum Message {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `first_word`
[INFO] [stdout]   --> src/main.rs:76:4
[INFO] [stdout]    |
[INFO] [stdout] 76 | fn first_word(s:&String)->&str{
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `about_slice`
[INFO] [stdout]   --> src/main.rs:87:4
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn about_slice(){
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `ownership_change`
[INFO] [stdout]   --> src/main.rs:98:4
[INFO] [stdout]    |
[INFO] [stdout] 98 | fn ownership_change()->String{
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `mutable_ref_example`
[INFO] [stdout]    --> src/main.rs:104:4
[INFO] [stdout]     |
[INFO] [stdout] 104 | fn mutable_ref_example(s:&mut String){
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `reference_example`
[INFO] [stdout]    --> src/main.rs:110:4
[INFO] [stdout]     |
[INFO] [stdout] 110 | fn reference_example(s:&String)->usize{
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `multipleReturnVal`
[INFO] [stdout]    --> src/main.rs:115:4
[INFO] [stdout]     |
[INFO] [stdout] 115 | fn multipleReturnVal(s:String)->(String, usize){
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `copyDeeply`
[INFO] [stdout]    --> src/main.rs:121:4
[INFO] [stdout]     |
[INFO] [stdout] 121 | fn copyDeeply() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `five`
[INFO] [stdout]    --> src/main.rs:129:4
[INFO] [stdout]     |
[INFO] [stdout] 129 | fn five()->i32{
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:43:9
[INFO] [stdout]    |
[INFO] [stdout] 43 |         handle(Command::from_args());
[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] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `multipleReturnVal` should have a snake case name
[INFO] [stdout]    --> src/main.rs:115:4
[INFO] [stdout]     |
[INFO] [stdout] 115 | fn multipleReturnVal(s:String)->(String, usize){
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `multiple_return_val`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `copyDeeply` should have a snake case name
[INFO] [stdout]    --> src/main.rs:121:4
[INFO] [stdout]     |
[INFO] [stdout] 121 | fn copyDeeply() {
[INFO] [stdout]     |    ^^^^^^^^^^ help: convert the identifier to snake case: `copy_deeply`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 15 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 41.26s
[INFO] running `Command { std: "docker" "inspect" "34aacc02dba01c591ad38a27b27c1b280f2b40ca6360c3ced9344d35ef95d449", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "34aacc02dba01c591ad38a27b27c1b280f2b40ca6360c3ced9344d35ef95d449", kill_on_drop: false }`
[INFO] [stdout] 34aacc02dba01c591ad38a27b27c1b280f2b40ca6360c3ced9344d35ef95d449
[INFO] running `Command { std: "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=warn" "-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@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4bd733ddd628f443d13a0484cc2e32a925a4a6f225528095309c66e10b499f9b
[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" "4bd733ddd628f443d13a0484cc2e32a925a4a6f225528095309c66e10b499f9b", kill_on_drop: false }`
[INFO] [stderr]    Compiling hello_cargo v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `word1`
[INFO] [stdout]   --> src/main.rs:59:9
[INFO] [stdout]    |
[INFO] [stdout] 59 |     let word1 = &my_str1[..];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_word1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/main.rs:57:15
[INFO] [stdout]    |
[INFO] [stdout] 57 | fn slice_show(s: &str) {
[INFO] [stdout]    |               ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct is never constructed: `User`
[INFO] [stdout]   --> src/main.rs:14:8
[INFO] [stdout]    |
[INFO] [stdout] 14 | struct User {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum is never used: `Message`
[INFO] [stdout]   --> src/main.rs:20:6
[INFO] [stdout]    |
[INFO] [stdout] 20 | enum Message {
[INFO] [stdout]    |      ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `first_word`
[INFO] [stdout]   --> src/main.rs:76:4
[INFO] [stdout]    |
[INFO] [stdout] 76 | fn first_word(s:&String)->&str{
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `about_slice`
[INFO] [stdout]   --> src/main.rs:87:4
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn about_slice(){
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `ownership_change`
[INFO] [stdout]   --> src/main.rs:98:4
[INFO] [stdout]    |
[INFO] [stdout] 98 | fn ownership_change()->String{
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `mutable_ref_example`
[INFO] [stdout]    --> src/main.rs:104:4
[INFO] [stdout]     |
[INFO] [stdout] 104 | fn mutable_ref_example(s:&mut String){
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `reference_example`
[INFO] [stdout]    --> src/main.rs:110:4
[INFO] [stdout]     |
[INFO] [stdout] 110 | fn reference_example(s:&String)->usize{
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `multipleReturnVal`
[INFO] [stdout]    --> src/main.rs:115:4
[INFO] [stdout]     |
[INFO] [stdout] 115 | fn multipleReturnVal(s:String)->(String, usize){
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `copyDeeply`
[INFO] [stdout]    --> src/main.rs:121:4
[INFO] [stdout]     |
[INFO] [stdout] 121 | fn copyDeeply() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `five`
[INFO] [stdout]    --> src/main.rs:129:4
[INFO] [stdout]     |
[INFO] [stdout] 129 | fn five()->i32{
[INFO] [stdout]     |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:43:9
[INFO] [stdout]    |
[INFO] [stdout] 43 |         handle(Command::from_args());
[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] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `multipleReturnVal` should have a snake case name
[INFO] [stdout]    --> src/main.rs:115:4
[INFO] [stdout]     |
[INFO] [stdout] 115 | fn multipleReturnVal(s:String)->(String, usize){
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `multiple_return_val`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `copyDeeply` should have a snake case name
[INFO] [stdout]    --> src/main.rs:121:4
[INFO] [stdout]     |
[INFO] [stdout] 121 | fn copyDeeply() {
[INFO] [stdout]     |    ^^^^^^^^^^ help: convert the identifier to snake case: `copy_deeply`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 15 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.31s
[INFO] running `Command { std: "docker" "inspect" "4bd733ddd628f443d13a0484cc2e32a925a4a6f225528095309c66e10b499f9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4bd733ddd628f443d13a0484cc2e32a925a4a6f225528095309c66e10b499f9b", kill_on_drop: false }`
[INFO] [stdout] 4bd733ddd628f443d13a0484cc2e32a925a4a6f225528095309c66e10b499f9b
[INFO] running `Command { std: "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=warn" "-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@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 6fe05bf434a28345ee0d29fee31f64340f35464f5b619fb7a3fd3e4b28c8f642
[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" "6fe05bf434a28345ee0d29fee31f64340f35464f5b619fb7a3fd3e4b28c8f642", kill_on_drop: false }`
[INFO] [stderr] warning: unused variable: `word1`
[INFO] [stderr]   --> src/main.rs:59:9
[INFO] [stderr]    |
[INFO] [stderr] 59 |     let word1 = &my_str1[..];
[INFO] [stderr]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_word1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s`
[INFO] [stderr]   --> src/main.rs:57:15
[INFO] [stderr]    |
[INFO] [stderr] 57 | fn slice_show(s: &str) {
[INFO] [stderr]    |               ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stderr] 
[INFO] [stderr] warning: struct is never constructed: `User`
[INFO] [stderr]   --> src/main.rs:14:8
[INFO] [stderr]    |
[INFO] [stderr] 14 | struct User {
[INFO] [stderr]    |        ^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: enum is never used: `Message`
[INFO] [stderr]   --> src/main.rs:20:6
[INFO] [stderr]    |
[INFO] [stderr] 20 | enum Message {
[INFO] [stderr]    |      ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `first_word`
[INFO] [stderr]   --> src/main.rs:76:4
[INFO] [stderr]    |
[INFO] [stderr] 76 | fn first_word(s:&String)->&str{
[INFO] [stderr]    |    ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `about_slice`
[INFO] [stderr]   --> src/main.rs:87:4
[INFO] [stderr]    |
[INFO] [stderr] 87 | fn about_slice(){
[INFO] [stderr]    |    ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `ownership_change`
[INFO] [stderr]   --> src/main.rs:98:4
[INFO] [stderr]    |
[INFO] [stderr] 98 | fn ownership_change()->String{
[INFO] [stderr]    |    ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `mutable_ref_example`
[INFO] [stderr]    --> src/main.rs:104:4
[INFO] [stderr]     |
[INFO] [stderr] 104 | fn mutable_ref_example(s:&mut String){
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `reference_example`
[INFO] [stderr]    --> src/main.rs:110:4
[INFO] [stderr]     |
[INFO] [stderr] 110 | fn reference_example(s:&String)->usize{
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `multipleReturnVal`
[INFO] [stderr]    --> src/main.rs:115:4
[INFO] [stderr]     |
[INFO] [stderr] 115 | fn multipleReturnVal(s:String)->(String, usize){
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `copyDeeply`
[INFO] [stderr]    --> src/main.rs:121:4
[INFO] [stderr]     |
[INFO] [stderr] 121 | fn copyDeeply() {
[INFO] [stderr]     |    ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `five`
[INFO] [stderr]    --> src/main.rs:129:4
[INFO] [stderr]     |
[INFO] [stderr] 129 | fn five()->i32{
[INFO] [stderr]     |    ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:43:9
[INFO] [stderr]    |
[INFO] [stderr] 43 |         handle(Command::from_args());
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: function `multipleReturnVal` should have a snake case name
[INFO] [stderr]    --> src/main.rs:115:4
[INFO] [stderr]     |
[INFO] [stderr] 115 | fn multipleReturnVal(s:String)->(String, usize){
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^ help: convert the identifier to snake case: `multiple_return_val`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function `copyDeeply` should have a snake case name
[INFO] [stderr]    --> src/main.rs:121:4
[INFO] [stderr]     |
[INFO] [stderr] 121 | fn copyDeeply() {
[INFO] [stderr]     |    ^^^^^^^^^^ help: convert the identifier to snake case: `copy_deeply`
[INFO] [stderr] 
[INFO] [stderr] warning: 15 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.12s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/hello_cargo-392b7ebb699ef48b
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "6fe05bf434a28345ee0d29fee31f64340f35464f5b619fb7a3fd3e4b28c8f642", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6fe05bf434a28345ee0d29fee31f64340f35464f5b619fb7a3fd3e4b28c8f642", kill_on_drop: false }`
[INFO] [stdout] 6fe05bf434a28345ee0d29fee31f64340f35464f5b619fb7a3fd3e4b28c8f642