[INFO] cloning repository https://github.com/minhphong306/learnrust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/minhphong306/learnrust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fminhphong306%2Flearnrust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fminhphong306%2Flearnrust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c272401e11c3af70df1d7a095fcbfcba712b79a2
[INFO] checking minhphong306/learnrust against try#59a256151e578f525a26127f2c3e3a6c7e2982ca for pr-149291-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fminhphong306%2Flearnrust" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/minhphong306/learnrust
[INFO] finished tweaking git repo https://github.com/minhphong306/learnrust
[INFO] tweaked toml for git repo https://github.com/minhphong306/learnrust written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/minhphong306/learnrust on toolchain 59a256151e578f525a26127f2c3e3a6c7e2982ca
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+59a256151e578f525a26127f2c3e3a6c7e2982ca" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/minhphong306/learnrust 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" "+59a256151e578f525a26127f2c3e3a6c7e2982ca" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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@sha256:94a0c148923f5b2b52a63ef0eeb1882ad339ab61bce784c8077cbe41c61feb6c" "/opt/rustwide/cargo-home/bin/cargo" "+59a256151e578f525a26127f2c3e3a6c7e2982ca" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 2e1a9457d94539989f1fefaa25bb8a297e1c2a75ebb157b1b42e0b280c4d329d
[INFO] running `Command { std: "docker" "start" "-a" "2e1a9457d94539989f1fefaa25bb8a297e1c2a75ebb157b1b42e0b280c4d329d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2e1a9457d94539989f1fefaa25bb8a297e1c2a75ebb157b1b42e0b280c4d329d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2e1a9457d94539989f1fefaa25bb8a297e1c2a75ebb157b1b42e0b280c4d329d", kill_on_drop: false }`
[INFO] [stdout] 2e1a9457d94539989f1fefaa25bb8a297e1c2a75ebb157b1b42e0b280c4d329d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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@sha256:94a0c148923f5b2b52a63ef0eeb1882ad339ab61bce784c8077cbe41c61feb6c" "/opt/rustwide/cargo-home/bin/cargo" "+59a256151e578f525a26127f2c3e3a6c7e2982ca" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 638db250dcff9b0d350b3ffdc585b108a5faff13d996e29abdece3c9dcaf3ce9
[INFO] running `Command { std: "docker" "start" "-a" "638db250dcff9b0d350b3ffdc585b108a5faff13d996e29abdece3c9dcaf3ce9", kill_on_drop: false }`
[INFO] [stderr]     Checking learnrust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `tuple2`
[INFO] [stdout]   --> src/main.rs:79:9
[INFO] [stdout]    |
[INFO] [stdout] 79 |     let tuple2 = (3, 5);
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_tuple2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `num` is never read
[INFO] [stdout]   --> src/main.rs:96:19
[INFO] [stdout]    |
[INFO] [stdout] 96 |     let mut num = 5;
[INFO] [stdout]    |                   ^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `str`
[INFO] [stdout]    --> src/main.rs:102:9
[INFO] [stdout]     |
[INFO] [stdout] 102 |     let str: &str = "hello world";
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_str`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `greet_world` is never used
[INFO] [stdout]  --> src/main.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn greet_world() {
[INFO] [stdout]   |    ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `penguin` is never used
[INFO] [stdout]   --> src/main.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn penguin() {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `variables_scalar` is never used
[INFO] [stdout]   --> src/main.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn variables_scalar() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `array` is never used
[INFO] [stdout]   --> src/main.rs:66:4
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn array() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `tuple` is never used
[INFO] [stdout]   --> src/main.rs:77:4
[INFO] [stdout]    |
[INFO] [stdout] 77 | fn tuple() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `function` is never used
[INFO] [stdout]   --> src/main.rs:86:4
[INFO] [stdout]    |
[INFO] [stdout] 86 | fn function() {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `mutability` is never used
[INFO] [stdout]   --> src/main.rs:95:4
[INFO] [stdout]    |
[INFO] [stdout] 95 | fn mutability() {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `string` is never used
[INFO] [stdout]    --> src/main.rs:101:4
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn string() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `array_and_slice` is never used
[INFO] [stdout]    --> src/main.rs:114:4
[INFO] [stdout]     |
[INFO] [stdout] 114 | fn array_and_slice() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `borrowing_slice` is never used
[INFO] [stdout]    --> src/main.rs:121:4
[INFO] [stdout]     |
[INFO] [stdout] 121 | fn borrowing_slice(arr: [u8; 4], slice: &[u8]) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `if_condition` is never used
[INFO] [stdout]    --> src/main.rs:128:4
[INFO] [stdout]     |
[INFO] [stdout] 128 | fn if_condition() {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `for_loop` is never used
[INFO] [stdout]    --> src/main.rs:139:4
[INFO] [stdout]     |
[INFO] [stdout] 139 | fn for_loop() {
[INFO] [stdout]     |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `while_loop` is never used
[INFO] [stdout]    --> src/main.rs:145:4
[INFO] [stdout]     |
[INFO] [stdout] 145 | fn while_loop() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `match_statement` is never used
[INFO] [stdout]    --> src/main.rs:158:4
[INFO] [stdout]     |
[INFO] [stdout] 158 | fn match_statement() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Bird` is never constructed
[INFO] [stdout]    --> src/main.rs:168:8
[INFO] [stdout]     |
[INFO] [stdout] 168 | struct Bird {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `print_name` is never used
[INFO] [stdout]    --> src/main.rs:174:8
[INFO] [stdout]     |
[INFO] [stdout] 173 | impl Bird {
[INFO] [stdout]     | --------- method in this implementation
[INFO] [stdout] 174 |     fn print_name(&self) {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `structs` is never used
[INFO] [stdout]    --> src/main.rs:179:4
[INFO] [stdout]     |
[INFO] [stdout] 179 | fn structs() {
[INFO] [stdout]     |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Animal` is never used
[INFO] [stdout]    --> src/main.rs:186:7
[INFO] [stdout]     |
[INFO] [stdout] 186 | trait Animal {
[INFO] [stdout]     |       ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `trail` is never used
[INFO] [stdout]    --> src/main.rs:203:4
[INFO] [stdout]     |
[INFO] [stdout] 203 | fn trail() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `MyEnum` is never used
[INFO] [stdout]    --> src/main.rs:208:6
[INFO] [stdout]     |
[INFO] [stdout] 208 | enum MyEnum {
[INFO] [stdout]     |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `longest_v1` is never used
[INFO] [stdout]    --> src/main.rs:237:4
[INFO] [stdout]     |
[INFO] [stdout] 237 | fn longest_v1<'a>(x: &'a str, y: &'a str) -> &'a str {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `test_lifetime_v1` is never used
[INFO] [stdout]    --> src/main.rs:245:4
[INFO] [stdout]     |
[INFO] [stdout] 245 | fn test_lifetime_v1() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `tuple2`
[INFO] [stdout]   --> src/main.rs:79:9
[INFO] [stdout]    |
[INFO] [stdout] 79 |     let tuple2 = (3, 5);
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_tuple2`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `num` is never read
[INFO] [stdout]   --> src/main.rs:96:19
[INFO] [stdout]    |
[INFO] [stdout] 96 |     let mut num = 5;
[INFO] [stdout]    |                   ^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `str`
[INFO] [stdout]    --> src/main.rs:102:9
[INFO] [stdout]     |
[INFO] [stdout] 102 |     let str: &str = "hello world";
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_str`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `core::str::<impl str>::len` that must be used
[INFO] [stdout]    --> src/main.rs:106:5
[INFO] [stdout]     |
[INFO] [stdout] 106 |     slice.len();
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 106 |     let _ = slice.len();
[INFO] [stdout]     |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `greet_world` is never used
[INFO] [stdout]  --> src/main.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn greet_world() {
[INFO] [stdout]   |    ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `penguin` is never used
[INFO] [stdout]   --> src/main.rs:14:4
[INFO] [stdout]    |
[INFO] [stdout] 14 | fn penguin() {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `variables_scalar` is never used
[INFO] [stdout]   --> src/main.rs:47:4
[INFO] [stdout]    |
[INFO] [stdout] 47 | fn variables_scalar() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `array` is never used
[INFO] [stdout]   --> src/main.rs:66:4
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn array() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `tuple` is never used
[INFO] [stdout]   --> src/main.rs:77:4
[INFO] [stdout]    |
[INFO] [stdout] 77 | fn tuple() {
[INFO] [stdout]    |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `function` is never used
[INFO] [stdout]   --> src/main.rs:86:4
[INFO] [stdout]    |
[INFO] [stdout] 86 | fn function() {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `mutability` is never used
[INFO] [stdout]   --> src/main.rs:95:4
[INFO] [stdout]    |
[INFO] [stdout] 95 | fn mutability() {
[INFO] [stdout]    |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `string` is never used
[INFO] [stdout]    --> src/main.rs:101:4
[INFO] [stdout]     |
[INFO] [stdout] 101 | fn string() {
[INFO] [stdout]     |    ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `array_and_slice` is never used
[INFO] [stdout]    --> src/main.rs:114:4
[INFO] [stdout]     |
[INFO] [stdout] 114 | fn array_and_slice() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `borrowing_slice` is never used
[INFO] [stdout]    --> src/main.rs:121:4
[INFO] [stdout]     |
[INFO] [stdout] 121 | fn borrowing_slice(arr: [u8; 4], slice: &[u8]) {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `if_condition` is never used
[INFO] [stdout]    --> src/main.rs:128:4
[INFO] [stdout]     |
[INFO] [stdout] 128 | fn if_condition() {
[INFO] [stdout]     |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `for_loop` is never used
[INFO] [stdout]    --> src/main.rs:139:4
[INFO] [stdout]     |
[INFO] [stdout] 139 | fn for_loop() {
[INFO] [stdout]     |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `while_loop` is never used
[INFO] [stdout]    --> src/main.rs:145:4
[INFO] [stdout]     |
[INFO] [stdout] 145 | fn while_loop() {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `match_statement` is never used
[INFO] [stdout]    --> src/main.rs:158:4
[INFO] [stdout]     |
[INFO] [stdout] 158 | fn match_statement() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Bird` is never constructed
[INFO] [stdout]    --> src/main.rs:168:8
[INFO] [stdout]     |
[INFO] [stdout] 168 | struct Bird {
[INFO] [stdout]     |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: method `print_name` is never used
[INFO] [stdout]    --> src/main.rs:174:8
[INFO] [stdout]     |
[INFO] [stdout] 173 | impl Bird {
[INFO] [stdout]     | --------- method in this implementation
[INFO] [stdout] 174 |     fn print_name(&self) {
[INFO] [stdout]     |        ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `structs` is never used
[INFO] [stdout]    --> src/main.rs:179:4
[INFO] [stdout]     |
[INFO] [stdout] 179 | fn structs() {
[INFO] [stdout]     |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Animal` is never used
[INFO] [stdout]    --> src/main.rs:186:7
[INFO] [stdout]     |
[INFO] [stdout] 186 | trait Animal {
[INFO] [stdout]     |       ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `trail` is never used
[INFO] [stdout]    --> src/main.rs:203:4
[INFO] [stdout]     |
[INFO] [stdout] 203 | fn trail() {
[INFO] [stdout]     |    ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `MyEnum` is never used
[INFO] [stdout]    --> src/main.rs:208:6
[INFO] [stdout]     |
[INFO] [stdout] 208 | enum MyEnum {
[INFO] [stdout]     |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `longest_v1` is never used
[INFO] [stdout]    --> src/main.rs:237:4
[INFO] [stdout]     |
[INFO] [stdout] 237 | fn longest_v1<'a>(x: &'a str, y: &'a str) -> &'a str {
[INFO] [stdout]     |    ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `test_lifetime_v1` is never used
[INFO] [stdout]    --> src/main.rs:245:4
[INFO] [stdout]     |
[INFO] [stdout] 245 | fn test_lifetime_v1() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `core::str::<impl str>::len` that must be used
[INFO] [stdout]    --> src/main.rs:106:5
[INFO] [stdout]     |
[INFO] [stdout] 106 |     slice.len();
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 106 |     let _ = slice.len();
[INFO] [stdout]     |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.14s
[INFO] running `Command { std: "docker" "inspect" "638db250dcff9b0d350b3ffdc585b108a5faff13d996e29abdece3c9dcaf3ce9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "638db250dcff9b0d350b3ffdc585b108a5faff13d996e29abdece3c9dcaf3ce9", kill_on_drop: false }`
[INFO] [stdout] 638db250dcff9b0d350b3ffdc585b108a5faff13d996e29abdece3c9dcaf3ce9