[INFO] cloning repository https://github.com/br1code/rust-common-concepts
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/br1code/rust-common-concepts" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbr1code%2Frust-common-concepts", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbr1code%2Frust-common-concepts'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 117c3ef8289b9f1840b279b4c5b39b784b3a4205
[INFO] checking br1code/rust-common-concepts against try#8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8 for pr-82565
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbr1code%2Frust-common-concepts" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/br1code/rust-common-concepts on toolchain 8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/br1code/rust-common-concepts
[INFO] finished tweaking git repo https://github.com/br1code/rust-common-concepts
[INFO] tweaked toml for git repo https://github.com/br1code/rust-common-concepts written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/br1code/rust-common-concepts already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "rustops/crates-build-env@sha256:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c076fc83b76bd4ce8f936ab9d4e760738c99e26a397ed02cd4e1df353b540f4f
[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" "c076fc83b76bd4ce8f936ab9d4e760738c99e26a397ed02cd4e1df353b540f4f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c076fc83b76bd4ce8f936ab9d4e760738c99e26a397ed02cd4e1df353b540f4f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c076fc83b76bd4ce8f936ab9d4e760738c99e26a397ed02cd4e1df353b540f4f", kill_on_drop: false }`
[INFO] [stdout] c076fc83b76bd4ce8f936ab9d4e760738c99e26a397ed02cd4e1df353b540f4f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+8e3afc79c11f48cb3acd1be5b3b7de98fe3f93a8" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3d7271f36d4c6079ef24360a8a0f315c2fb08932abd2e1d13f0ecef85d674493
[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" "3d7271f36d4c6079ef24360a8a0f315c2fb08932abd2e1d13f0ecef85d674493", kill_on_drop: false }`
[INFO] [stderr]     Checking rust-common-concepts v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unreachable statement
[INFO] [stdout]   --> src/control_flow.rs:40:5
[INFO] [stdout]    |
[INFO] [stdout] 35 | /     loop {
[INFO] [stdout] 36 | |         println!("again!");
[INFO] [stdout] 37 | |     }
[INFO] [stdout]    | |_____- any code following this expression is unreachable
[INFO] [stdout] ...
[INFO] [stdout] 40 | /     loop {
[INFO] [stdout] 41 | |         print!("just one time");
[INFO] [stdout] 42 | |         break;
[INFO] [stdout] 43 | |     }
[INFO] [stdout]    | |_____^ unreachable statement
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable statement
[INFO] [stdout]   --> src/control_flow.rs:40:5
[INFO] [stdout]    |
[INFO] [stdout] 35 | /     loop {
[INFO] [stdout] 36 | |         println!("again!");
[INFO] [stdout] 37 | |     }
[INFO] [stdout]    | |_____- any code following this expression is unreachable
[INFO] [stdout] ...
[INFO] [stdout] 40 | /     loop {
[INFO] [stdout] 41 | |         print!("just one time");
[INFO] [stdout] 42 | |         break;
[INFO] [stdout] 43 | |     }
[INFO] [stdout]    | |_____^ unreachable statement
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/data_types.rs:33:9
[INFO] [stdout]    |
[INFO] [stdout] 33 |     let x = 2.0; // f64 default
[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/data_types.rs:35:9
[INFO] [stdout]    |
[INFO] [stdout] 35 |     let y: f32 = 3.0; // f32
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sum`
[INFO] [stdout]   --> src/data_types.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     let sum = 5 + 10;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_sum`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `difference`
[INFO] [stdout]   --> src/data_types.rs:43:9
[INFO] [stdout]    |
[INFO] [stdout] 43 |     let difference = 95.5 - 4.3;
[INFO] [stdout]    |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_difference`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `product`
[INFO] [stdout]   --> src/data_types.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let product = 4 * 30;
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_product`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `quotient`
[INFO] [stdout]   --> src/data_types.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let quotient = 56.7 / 32.2;
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_quotient`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `remainder`
[INFO] [stdout]   --> src/data_types.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let remainder = 43 % 5;
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_remainder`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> src/data_types.rs:57:9
[INFO] [stdout]    |
[INFO] [stdout] 57 |     let t = true;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/data_types.rs:59:9
[INFO] [stdout]    |
[INFO] [stdout] 59 |     let f: bool = false; // with explicit type annotation
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/data_types.rs:64:9
[INFO] [stdout]    |
[INFO] [stdout] 64 |     let c = 'z';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/data_types.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let z = 'ℤ';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `heart_eyed_cat`
[INFO] [stdout]   --> src/data_types.rs:66:9
[INFO] [stdout]    |
[INFO] [stdout] 66 |     let heart_eyed_cat = '😻';
[INFO] [stdout]    |         ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_heart_eyed_cat`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/data_types.rs:85:10
[INFO] [stdout]    |
[INFO] [stdout] 85 |     let (x, y, z) = tup;
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/data_types.rs:85:16
[INFO] [stdout]    |
[INFO] [stdout] 85 |     let (x, y, z) = tup;
[INFO] [stdout]    |                ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `five_hundred`
[INFO] [stdout]   --> src/data_types.rs:93:9
[INFO] [stdout]    |
[INFO] [stdout] 93 |     let five_hundred = tup.0;
[INFO] [stdout]    |         ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_five_hundred`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six_point_four`
[INFO] [stdout]   --> src/data_types.rs:94:9
[INFO] [stdout]    |
[INFO] [stdout] 94 |     let six_point_four = tup.1;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_six_point_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `one`
[INFO] [stdout]   --> src/data_types.rs:95:9
[INFO] [stdout]    |
[INFO] [stdout] 95 |     let one = tup.2;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_one`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_array`
[INFO] [stdout]    --> src/data_types.rs:102:9
[INFO] [stdout]     |
[INFO] [stdout] 102 |     let my_array = [1, 2, 3, 4, 5];
[INFO] [stdout]     |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_my_array`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `months`
[INFO] [stdout]    --> src/data_types.rs:112:9
[INFO] [stdout]     |
[INFO] [stdout] 112 |     let months = ["January", "February", "March", "April", "May", "June", "July",
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_months`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `array`
[INFO] [stdout]    --> src/data_types.rs:117:9
[INFO] [stdout]     |
[INFO] [stdout] 117 |     let array: [i32; 5] = [1, 2, 3, 4, 5];
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_array`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `filled`
[INFO] [stdout]    --> src/data_types.rs:123:9
[INFO] [stdout]     |
[INFO] [stdout] 123 |     let filled = [3; 5]; // the same as writing let filled = [3, 3, 3, 3, 3]
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_filled`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `first`
[INFO] [stdout]    --> src/data_types.rs:128:9
[INFO] [stdout]     |
[INFO] [stdout] 128 |     let first = a[0]; // 1
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_first`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `second`
[INFO] [stdout]    --> src/data_types.rs:129:9
[INFO] [stdout]     |
[INFO] [stdout] 129 |     let second = a[2]; // 2
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_second`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `element`
[INFO] [stdout]    --> src/data_types.rs:136:9
[INFO] [stdout]     |
[INFO] [stdout] 136 |     let element = a[index];
[INFO] [stdout]     |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_element`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `spaces`
[INFO] [stdout]   --> src/variables_and_mutability.rs:68:9
[INFO] [stdout]    |
[INFO] [stdout] 68 |     let spaces = spaces.len(); // usize
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_spaces`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `spaces`
[INFO] [stdout]   --> src/variables_and_mutability.rs:71:9
[INFO] [stdout]    |
[INFO] [stdout] 71 |     let mut spaces = "   ";
[INFO] [stdout]    |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_spaces`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/data_types.rs:33:9
[INFO] [stdout]    |
[INFO] [stdout] 33 |     let x = 2.0; // f64 default
[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/data_types.rs:35:9
[INFO] [stdout]    |
[INFO] [stdout] 35 |     let y: f32 = 3.0; // f32
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sum`
[INFO] [stdout]   --> src/data_types.rs:40:9
[INFO] [stdout]    |
[INFO] [stdout] 40 |     let sum = 5 + 10;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_sum`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `difference`
[INFO] [stdout]   --> src/data_types.rs:43:9
[INFO] [stdout]    |
[INFO] [stdout] 43 |     let difference = 95.5 - 4.3;
[INFO] [stdout]    |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_difference`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `product`
[INFO] [stdout]   --> src/data_types.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let product = 4 * 30;
[INFO] [stdout]    |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_product`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `quotient`
[INFO] [stdout]   --> src/data_types.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let quotient = 56.7 / 32.2;
[INFO] [stdout]    |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_quotient`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `remainder`
[INFO] [stdout]   --> src/data_types.rs:52:9
[INFO] [stdout]    |
[INFO] [stdout] 52 |     let remainder = 43 % 5;
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_remainder`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> src/data_types.rs:57:9
[INFO] [stdout]    |
[INFO] [stdout] 57 |     let t = true;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/data_types.rs:59:9
[INFO] [stdout]    |
[INFO] [stdout] 59 |     let f: bool = false; // with explicit type annotation
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/data_types.rs:64:9
[INFO] [stdout]    |
[INFO] [stdout] 64 |     let c = 'z';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/data_types.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let z = 'ℤ';
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `heart_eyed_cat`
[INFO] [stdout]   --> src/data_types.rs:66:9
[INFO] [stdout]    |
[INFO] [stdout] 66 |     let heart_eyed_cat = '😻';
[INFO] [stdout]    |         ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_heart_eyed_cat`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/data_types.rs:85:10
[INFO] [stdout]    |
[INFO] [stdout] 85 |     let (x, y, z) = tup;
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> src/data_types.rs:85:16
[INFO] [stdout]    |
[INFO] [stdout] 85 |     let (x, y, z) = tup;
[INFO] [stdout]    |                ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `five_hundred`
[INFO] [stdout]   --> src/data_types.rs:93:9
[INFO] [stdout]    |
[INFO] [stdout] 93 |     let five_hundred = tup.0;
[INFO] [stdout]    |         ^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_five_hundred`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six_point_four`
[INFO] [stdout]   --> src/data_types.rs:94:9
[INFO] [stdout]    |
[INFO] [stdout] 94 |     let six_point_four = tup.1;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_six_point_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `one`
[INFO] [stdout]   --> src/data_types.rs:95:9
[INFO] [stdout]    |
[INFO] [stdout] 95 |     let one = tup.2;
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_one`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_array`
[INFO] [stdout]    --> src/data_types.rs:102:9
[INFO] [stdout]     |
[INFO] [stdout] 102 |     let my_array = [1, 2, 3, 4, 5];
[INFO] [stdout]     |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_my_array`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `months`
[INFO] [stdout]    --> src/data_types.rs:112:9
[INFO] [stdout]     |
[INFO] [stdout] 112 |     let months = ["January", "February", "March", "April", "May", "June", "July",
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_months`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `array`
[INFO] [stdout]    --> src/data_types.rs:117:9
[INFO] [stdout]     |
[INFO] [stdout] 117 |     let array: [i32; 5] = [1, 2, 3, 4, 5];
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_array`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `filled`
[INFO] [stdout]    --> src/data_types.rs:123:9
[INFO] [stdout]     |
[INFO] [stdout] 123 |     let filled = [3; 5]; // the same as writing let filled = [3, 3, 3, 3, 3]
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_filled`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `first`
[INFO] [stdout]    --> src/data_types.rs:128:9
[INFO] [stdout]     |
[INFO] [stdout] 128 |     let first = a[0]; // 1
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_first`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `second`
[INFO] [stdout]    --> src/data_types.rs:129:9
[INFO] [stdout]     |
[INFO] [stdout] 129 |     let second = a[2]; // 2
[INFO] [stdout]     |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_second`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `element`
[INFO] [stdout]    --> src/data_types.rs:136:9
[INFO] [stdout]     |
[INFO] [stdout] 136 |     let element = a[index];
[INFO] [stdout]     |         ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_element`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `spaces`
[INFO] [stdout]   --> src/variables_and_mutability.rs:68:9
[INFO] [stdout]    |
[INFO] [stdout] 68 |     let spaces = spaces.len(); // usize
[INFO] [stdout]    |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_spaces`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `spaces`
[INFO] [stdout]   --> src/variables_and_mutability.rs:71:9
[INFO] [stdout]    |
[INFO] [stdout] 71 |     let mut spaces = "   ";
[INFO] [stdout]    |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_spaces`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/variables_and_mutability.rs:71:9
[INFO] [stdout]    |
[INFO] [stdout] 71 |     let mut spaces = "   ";
[INFO] [stdout]    |         ----^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/exercises.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fahrenheit_to_celsius`
[INFO] [stdout]   --> src/exercises.rs:17:4
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn fahrenheit_to_celsius(f: f64) -> f64 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `celsius_to_fahrenheit`
[INFO] [stdout]   --> src/exercises.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn celsius_to_fahrenheit(c: f64) -> f64 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fib`
[INFO] [stdout]   --> src/exercises.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn fib(n: u32) -> u32 {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/control_flow.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/functions.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `do_something`
[INFO] [stdout]   --> src/functions.rs:10:4
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn do_something() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `another_function`
[INFO] [stdout]   --> src/functions.rs:18:4
[INFO] [stdout]    |
[INFO] [stdout] 18 | fn another_function(x: i32) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `and_another_function`
[INFO] [stdout]   --> src/functions.rs:26:4
[INFO] [stdout]    |
[INFO] [stdout] 26 | fn and_another_function(x: i32, y: i32) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `five`
[INFO] [stdout]   --> src/functions.rs:37:4
[INFO] [stdout]    |
[INFO] [stdout] 37 | fn five() -> i32 {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `plus_one`
[INFO] [stdout]   --> src/functions.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn plus_one(x: i32) -> i32 {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/data_types.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/variables_and_mutability.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/variables_and_mutability.rs:71:9
[INFO] [stdout]    |
[INFO] [stdout] 71 |     let mut spaces = "   ";
[INFO] [stdout]    |         ----^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/exercises.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fahrenheit_to_celsius`
[INFO] [stdout]   --> src/exercises.rs:17:4
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn fahrenheit_to_celsius(f: f64) -> f64 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `celsius_to_fahrenheit`
[INFO] [stdout]   --> src/exercises.rs:21:4
[INFO] [stdout]    |
[INFO] [stdout] 21 | fn celsius_to_fahrenheit(c: f64) -> f64 {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `fib`
[INFO] [stdout]   --> src/exercises.rs:25:4
[INFO] [stdout]    |
[INFO] [stdout] 25 | fn fib(n: u32) -> u32 {
[INFO] [stdout]    |    ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/control_flow.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/functions.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `do_something`
[INFO] [stdout]   --> src/functions.rs:10:4
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn do_something() {
[INFO] [stdout]    |    ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `another_function`
[INFO] [stdout]   --> src/functions.rs:18:4
[INFO] [stdout]    |
[INFO] [stdout] 18 | fn another_function(x: i32) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `and_another_function`
[INFO] [stdout]   --> src/functions.rs:26:4
[INFO] [stdout]    |
[INFO] [stdout] 26 | fn and_another_function(x: i32, y: i32) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `five`
[INFO] [stdout]   --> src/functions.rs:37:4
[INFO] [stdout]    |
[INFO] [stdout] 37 | fn five() -> i32 {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `plus_one`
[INFO] [stdout]   --> src/functions.rs:44:4
[INFO] [stdout]    |
[INFO] [stdout] 44 | fn plus_one(x: i32) -> i32 {
[INFO] [stdout]    |    ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/data_types.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `main`
[INFO] [stdout]  --> src/variables_and_mutability.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn main() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 41 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 41 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.24s
[INFO] running `Command { std: "docker" "inspect" "3d7271f36d4c6079ef24360a8a0f315c2fb08932abd2e1d13f0ecef85d674493", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3d7271f36d4c6079ef24360a8a0f315c2fb08932abd2e1d13f0ecef85d674493", kill_on_drop: false }`
[INFO] [stdout] 3d7271f36d4c6079ef24360a8a0f315c2fb08932abd2e1d13f0ecef85d674493