[INFO] cloning repository https://github.com/jt-rose/rust_basics
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/jt-rose/rust_basics" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjt-rose%2Frust_basics", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjt-rose%2Frust_basics'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7712e7bf7ff82a89ba7e35c0c175bb5863222909
[INFO] checking jt-rose/rust_basics against master#9c67cecd12d79f1bbc00a74f70e7ef9fff086a5a for pr-138458
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjt-rose%2Frust_basics" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/jt-rose/rust_basics on toolchain 9c67cecd12d79f1bbc00a74f70e7ef9fff086a5a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9c67cecd12d79f1bbc00a74f70e7ef9fff086a5a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/jt-rose/rust_basics
[INFO] finished tweaking git repo https://github.com/jt-rose/rust_basics
[INFO] tweaked toml for git repo https://github.com/jt-rose/rust_basics written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/jt-rose/rust_basics 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" "+9c67cecd12d79f1bbc00a74f70e7ef9fff086a5a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/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@sha256:1680c8fbd8dfb46fcd6d22e546df16ab0e007457dc29fcd9e987cdd5077fd1af" "/opt/rustwide/cargo-home/bin/cargo" "+9c67cecd12d79f1bbc00a74f70e7ef9fff086a5a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 171e5406c52e74dc379ac9961c2ce1eab64c82208d42ef07ebd824f9ab4423c5
[INFO] running `Command { std: "docker" "start" "-a" "171e5406c52e74dc379ac9961c2ce1eab64c82208d42ef07ebd824f9ab4423c5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "171e5406c52e74dc379ac9961c2ce1eab64c82208d42ef07ebd824f9ab4423c5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "171e5406c52e74dc379ac9961c2ce1eab64c82208d42ef07ebd824f9ab4423c5", kill_on_drop: false }`
[INFO] [stdout] 171e5406c52e74dc379ac9961c2ce1eab64c82208d42ef07ebd824f9ab4423c5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/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@sha256:1680c8fbd8dfb46fcd6d22e546df16ab0e007457dc29fcd9e987cdd5077fd1af" "/opt/rustwide/cargo-home/bin/cargo" "+9c67cecd12d79f1bbc00a74f70e7ef9fff086a5a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 82f74c70690f4567a309098ead94ec9dce77df91921f9c87897784b6e0f65226
[INFO] running `Command { std: "docker" "start" "-a" "82f74c70690f4567a309098ead94ec9dce77df91921f9c87897784b6e0f65226", kill_on_drop: false }`
[INFO] [stderr]     Checking rust_basics v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:26:9
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let x = 7;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/main.rs:27:9
[INFO] [stdout]    |
[INFO] [stdout] 27 |     let y = 9;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `z` is assigned to, but never used
[INFO] [stdout]   --> src/main.rs:28:13
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let mut z = 10;
[INFO] [stdout]    |             ^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_z` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `z` is never read
[INFO] [stdout]   --> src/main.rs:29:5
[INFO] [stdout]    |
[INFO] [stdout] 29 |     z = 200;
[INFO] [stdout]    |     ^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `m`
[INFO] [stdout]   --> src/main.rs:33:9
[INFO] [stdout]    |
[INFO] [stdout] 33 |     let m = m + 1;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_m`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `abc`
[INFO] [stdout]   --> src/main.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let abc = abc.len();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_abc`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x64`
[INFO] [stdout]   --> src/main.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let x64: i64 = 123456;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_x64`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/main.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let a = 2.0;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/main.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |     let b: f32 = 1.0;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/main.rs:53:9
[INFO] [stdout]    |
[INFO] [stdout] 53 |     let c = 'C';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `tup`
[INFO] [stdout]   --> src/main.rs:64:9
[INFO] [stdout]    |
[INFO] [stdout] 64 |     let tup: (i32, f64, u8, f32) = (500, 6.4, 1, 29.29);
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_tup`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:26:9
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let x = 7;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/main.rs:27:9
[INFO] [stdout]    |
[INFO] [stdout] 27 |     let y = 9;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `z` is assigned to, but never used
[INFO] [stdout]   --> src/main.rs:28:13
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let mut z = 10;
[INFO] [stdout]    |             ^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_z` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `z` is never read
[INFO] [stdout]   --> src/main.rs:29:5
[INFO] [stdout]    |
[INFO] [stdout] 29 |     z = 200;
[INFO] [stdout]    |     ^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `m`
[INFO] [stdout]   --> src/main.rs:33:9
[INFO] [stdout]    |
[INFO] [stdout] 33 |     let m = m + 1;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_m`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `abc`
[INFO] [stdout]   --> src/main.rs:37:9
[INFO] [stdout]    |
[INFO] [stdout] 37 |     let abc = abc.len();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_abc`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x64`
[INFO] [stdout]   --> src/main.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let x64: i64 = 123456;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_x64`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/main.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let a = 2.0;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/main.rs:50:9
[INFO] [stdout]    |
[INFO] [stdout] 50 |     let b: f32 = 1.0;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/main.rs:53:9
[INFO] [stdout]    |
[INFO] [stdout] 53 |     let c = 'C';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `tup`
[INFO] [stdout]   --> src/main.rs:64:9
[INFO] [stdout]    |
[INFO] [stdout] 64 |     let tup: (i32, f64, u8, f32) = (500, 6.4, 1, 29.29);
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_tup`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/main.rs:69:10
[INFO] [stdout]    |
[INFO] [stdout] 69 |     let (f, g) = tup2;
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `g`
[INFO] [stdout]   --> src/main.rs:69:13
[INFO] [stdout]    |
[INFO] [stdout] 69 |     let (f, g) = tup2;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_g`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arr`
[INFO] [stdout]   --> src/main.rs:72:9
[INFO] [stdout]    |
[INFO] [stdout] 72 |     let arr = [1,2,3,4,5];
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_arr`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `emptyArr`
[INFO] [stdout]   --> src/main.rs:74:9
[INFO] [stdout]    |
[INFO] [stdout] 74 |     let emptyArr = [0; 3];
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_emptyArr`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `calculated_var`
[INFO] [stdout]   --> src/main.rs:78:9
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let calculated_var = {
[INFO] [stdout]    |         ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_calculated_var`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `add5`
[INFO] [stdout]    --> src/main.rs:122:9
[INFO] [stdout]     |
[INFO] [stdout] 122 |     let add5 = move |x| add(5, x);
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_add5`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]    --> src/main.rs:146:9
[INFO] [stdout]     |
[INFO] [stdout] 146 |     let result = loop {
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_numbers`
[INFO] [stdout]    --> src/main.rs:167:9
[INFO] [stdout]     |
[INFO] [stdout] 167 |     let my_numbers = [1, 2, 3];
[INFO] [stdout]     |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_my_numbers`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/main.rs:69:10
[INFO] [stdout]    |
[INFO] [stdout] 69 |     let (f, g) = tup2;
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `g`
[INFO] [stdout]   --> src/main.rs:69:13
[INFO] [stdout]    |
[INFO] [stdout] 69 |     let (f, g) = tup2;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_g`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arr`
[INFO] [stdout]   --> src/main.rs:72:9
[INFO] [stdout]    |
[INFO] [stdout] 72 |     let arr = [1,2,3,4,5];
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_arr`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `emptyArr`
[INFO] [stdout]   --> src/main.rs:74:9
[INFO] [stdout]    |
[INFO] [stdout] 74 |     let emptyArr = [0; 3];
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_emptyArr`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `calculated_var`
[INFO] [stdout]   --> src/main.rs:78:9
[INFO] [stdout]    |
[INFO] [stdout] 78 |     let calculated_var = {
[INFO] [stdout]    |         ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_calculated_var`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `add5`
[INFO] [stdout]    --> src/main.rs:122:9
[INFO] [stdout]     |
[INFO] [stdout] 122 |     let add5 = move |x| add(5, x);
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_add5`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `result`
[INFO] [stdout]    --> src/main.rs:146:9
[INFO] [stdout]     |
[INFO] [stdout] 146 |     let result = loop {
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_result`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_numbers`
[INFO] [stdout]    --> src/main.rs:167:9
[INFO] [stdout]     |
[INFO] [stdout] 167 |     let my_numbers = [1, 2, 3];
[INFO] [stdout]     |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_my_numbers`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `PI` is never used
[INFO] [stdout]   --> src/main.rs:40:11
[INFO] [stdout]    |
[INFO] [stdout] 40 |     const PI: f32 = 3.14;
[INFO] [stdout]    |           ^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `double` is never used
[INFO] [stdout]    --> src/main.rs:103:8
[INFO] [stdout]     |
[INFO] [stdout] 103 |     fn double(num: i32) -> i32 {
[INFO] [stdout]     |        ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `String::is_empty` that must be used
[INFO] [stdout]   --> src/main.rs:60:5
[INFO] [stdout]    |
[INFO] [stdout] 60 |     my_string.is_empty();
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 60 |     let _ = my_string.is_empty();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `String::len` that must be used
[INFO] [stdout]   --> src/main.rs:61:5
[INFO] [stdout]    |
[INFO] [stdout] 61 |     my_string.len();
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 61 |     let _ = my_string.len();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `emptyArr` should have a snake case name
[INFO] [stdout]   --> src/main.rs:74:9
[INFO] [stdout]    |
[INFO] [stdout] 74 |     let emptyArr = [0; 3];
[INFO] [stdout]    |         ^^^^^^^^ help: convert the identifier to snake case: `empty_arr`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `String::is_empty` that must be used
[INFO] [stdout]   --> src/main.rs:60:5
[INFO] [stdout]    |
[INFO] [stdout] 60 |     my_string.is_empty();
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 60 |     let _ = my_string.is_empty();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `String::len` that must be used
[INFO] [stdout]   --> src/main.rs:61:5
[INFO] [stdout]    |
[INFO] [stdout] 61 |     my_string.len();
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 61 |     let _ = my_string.len();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `emptyArr` should have a snake case name
[INFO] [stdout]   --> src/main.rs:74:9
[INFO] [stdout]    |
[INFO] [stdout] 74 |     let emptyArr = [0; 3];
[INFO] [stdout]    |         ^^^^^^^^ help: convert the identifier to snake case: `empty_arr`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.21s
[INFO] running `Command { std: "docker" "inspect" "82f74c70690f4567a309098ead94ec9dce77df91921f9c87897784b6e0f65226", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "82f74c70690f4567a309098ead94ec9dce77df91921f9c87897784b6e0f65226", kill_on_drop: false }`
[INFO] [stdout] 82f74c70690f4567a309098ead94ec9dce77df91921f9c87897784b6e0f65226