[INFO] cloning repository https://github.com/KrzysztofLembryk/rust_learning
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/KrzysztofLembryk/rust_learning" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FKrzysztofLembryk%2Frust_learning", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FKrzysztofLembryk%2Frust_learning'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1ad82c9e32ff2478fefc4b9eb376b1d842e248b0
[INFO] fixing KrzysztofLembryk/rust_learning against try#622891a4e29178280638a6b63a8908bde2c0c854+cargoflags=-Zfix-edition=start=2015 for pr-157817-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FKrzysztofLembryk%2Frust_learning" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/KrzysztofLembryk/rust_learning
[INFO] finished tweaking git repo https://github.com/KrzysztofLembryk/rust_learning
[INFO] tweaked toml for git repo https://github.com/KrzysztofLembryk/rust_learning written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/KrzysztofLembryk/rust_learning on toolchain 622891a4e29178280638a6b63a8908bde2c0c854
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/KrzysztofLembryk/rust_learning 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" "+622891a4e29178280638a6b63a8908bde2c0c854" "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-6-tc1/source:/opt/rustwide/workdir:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,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" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3a6becf2bc8dde7f3fa57ede90e4f284e72d296796fc446bbb1e2c7cc0530151" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2
[INFO] running `Command { std: "docker" "start" "8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2" "/opt/rustwide/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=" "-e" "RUSTDOCFLAGS=" "-w" "/opt/rustwide/workdir" "--user" "0:0" "8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2" "/opt/rustwide/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "fix" "--allow-no-vcs" "--allow-dirty" "--frozen" "--all" "--all-targets" "--message-format=json" "-Zfix-edition=start=2015", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.177
[INFO] [stderr]     Checking getrandom v0.2.16
[INFO] [stderr]     Checking rand_core v0.6.4
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking rand v0.8.5
[INFO] [stderr]     Checking rust_progr_lang_course v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0252]: the name `chapter_15_deref` is defined multiple times
[INFO] [stdout]   --> src/main.rs:41:5
[INFO] [stdout]    |
[INFO] [stdout] 15 |     chapter_15_deref
[INFO] [stdout]    |     ---------------- previous import of the value `chapter_15_deref` here
[INFO] [stdout] ...
[INFO] [stdout] 41 | use crate::smart_pointers::chapter_15_deref;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `chapter_15_deref` reimported here
[INFO] [stdout]    |
[INFO] [stdout]    = note: `chapter_15_deref` must be defined only once in the value namespace of this module
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0252]: the name `chapter_15_deref` is defined multiple times
[INFO] [stdout]   --> src/main.rs:41:5
[INFO] [stdout]    |
[INFO] [stdout] 15 |     chapter_15_deref
[INFO] [stdout]    |     ---------------- previous import of the value `chapter_15_deref` here
[INFO] [stdout] ...
[INFO] [stdout] 41 | use crate::smart_pointers::chapter_15_deref;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `chapter_15_deref` reimported here
[INFO] [stdout]    |
[INFO] [stdout]    = note: `chapter_15_deref` must be defined only once in the value namespace of this module
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cell::RefMut`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cell::RefMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fs`
[INFO] [stdout]  --> src/minigrep.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::fs;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary trailing semicolon
[INFO] [stdout]   --> src/iterators_closures.rs:77:6
[INFO] [stdout]    |
[INFO] [stdout] 77 |     };
[INFO] [stdout]    |      ^ help: remove this semicolon
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(redundant_semicolons)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cell::RefMut`
[INFO] [stdout]  --> src/main.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::cell::RefMut;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::fs`
[INFO] [stdout]  --> src/minigrep.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::fs;
[INFO] [stdout]   |     ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary trailing semicolon
[INFO] [stdout]   --> src/iterators_closures.rs:77:6
[INFO] [stdout]    |
[INFO] [stdout] 77 |     };
[INFO] [stdout]    |      ^ help: remove this semicolon
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(redundant_semicolons)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `chapter_15_deref`
[INFO] [stdout]   --> src/main.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 15 |     chapter_15_deref
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `chapter_15_deref`
[INFO] [stdout]   --> src/main.rs:15:5
[INFO] [stdout]    |
[INFO] [stdout] 15 |     chapter_15_deref
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `chapter_5_1_structs`, `chapter_5_2_exmpl_prog_with_structs`, `chapter_5_3_struct_methods`, and `chapter_6_2_MATCH`
[INFO] [stdout]   --> src/main.rs:18:21
[INFO] [stdout]    |
[INFO] [stdout] 18 | use structs_enums::{chapter_5_1_structs, 
[INFO] [stdout]    |                     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 19 |     chapter_5_2_exmpl_prog_with_structs,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 20 |     chapter_5_3_struct_methods,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 21 |     chapter_6_2_MATCH};
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `chapter_8_strings` and `chapter_8_vectors`
[INFO] [stdout]   --> src/main.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 24 |     chapter_8_vectors,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 25 |     chapter_8_strings
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `chapter_9_recoverable_errors`
[INFO] [stdout]   --> src/main.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 30 |     chapter_9_recoverable_errors
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `chapter_5_1_structs`, `chapter_5_2_exmpl_prog_with_structs`, `chapter_5_3_struct_methods`, and `chapter_6_2_MATCH`
[INFO] [stdout]   --> src/main.rs:18:21
[INFO] [stdout]    |
[INFO] [stdout] 18 | use structs_enums::{chapter_5_1_structs, 
[INFO] [stdout]    |                     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 19 |     chapter_5_2_exmpl_prog_with_structs,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 20 |     chapter_5_3_struct_methods,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 21 |     chapter_6_2_MATCH};
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `chapter_10_generics`
[INFO] [stdout]   --> src/main.rs:34:5
[INFO] [stdout]    |
[INFO] [stdout] 34 |     chapter_10_generics
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `crate::smart_pointers::chapter_15_deref`
[INFO] [stdout]   --> src/main.rs:41:5
[INFO] [stdout]    |
[INFO] [stdout] 41 | use crate::smart_pointers::chapter_15_deref;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `chapter_8_strings` and `chapter_8_vectors`
[INFO] [stdout]   --> src/main.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 24 |     chapter_8_vectors,
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 25 |     chapter_8_strings
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `chapter_9_recoverable_errors`
[INFO] [stdout]   --> src/main.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 30 |     chapter_9_recoverable_errors
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `chapter_10_generics`
[INFO] [stdout]   --> src/main.rs:34:5
[INFO] [stdout]    |
[INFO] [stdout] 34 |     chapter_10_generics
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `crate::smart_pointers::chapter_15_deref`
[INFO] [stdout]   --> src/main.rs:41:5
[INFO] [stdout]    |
[INFO] [stdout] 41 | use crate::smart_pointers::chapter_15_deref;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]    --> src/structs_enums.rs:134:9
[INFO] [stdout]     |
[INFO] [stdout] 134 |     let six = plus_one(five);
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]    --> src/structs_enums.rs:135:9
[INFO] [stdout]     |
[INFO] [stdout] 135 |     let none = plus_one(None);
[INFO] [stdout]     |         ^^^^
[INFO] [stdout]     |
[INFO] [stdout] help: you might have meant to pattern match on the similarly named variant `None`
[INFO] [stdout]     |
[INFO] [stdout] 135 -     let none = plus_one(None);
[INFO] [stdout] 135 +     let std::prelude::v1::None = plus_one(None);
[INFO] [stdout]     |
[INFO] [stdout] help: if this is intentional, prefix it with an underscore
[INFO] [stdout]     |
[INFO] [stdout] 135 |     let _none = plus_one(None);
[INFO] [stdout]     |         +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_spaces`
[INFO] [stdout]    --> src/structs_enums.rs:160:20
[INFO] [stdout]     |
[INFO] [stdout] 160 |     fn move_player(num_spaces: u8) {}
[INFO] [stdout]     |                    ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_spaces`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_number`
[INFO] [stdout]    --> src/structs_enums.rs:182:9
[INFO] [stdout]     |
[INFO] [stdout] 182 |     let some_number = Some(5);
[INFO] [stdout]     |         ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_char`
[INFO] [stdout]    --> src/structs_enums.rs:183:9
[INFO] [stdout]     |
[INFO] [stdout] 183 |     let some_char = Some('e');
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_char`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `absent_number`
[INFO] [stdout]    --> src/structs_enums.rs:187:9
[INFO] [stdout]     |
[INFO] [stdout] 187 |     let absent_number: Option<i32> = None;
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_absent_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_four`
[INFO] [stdout]    --> src/structs_enums.rs:211:13
[INFO] [stdout]     |
[INFO] [stdout] 211 |         let ip_four = IpAddrKind::V4;
[INFO] [stdout]     |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_six`
[INFO] [stdout]    --> src/structs_enums.rs:212:13
[INFO] [stdout]     |
[INFO] [stdout] 212 |         let ip_six = IpAddrKind::V6;
[INFO] [stdout]     |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_six`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_ip`
[INFO] [stdout]    --> src/structs_enums.rs:231:13
[INFO] [stdout]     |
[INFO] [stdout] 231 |         let my_ip = IpAddr::V4(String::from("127.0.0.1"));
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_my_ip`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]    --> src/structs_enums.rs:245:13
[INFO] [stdout]     |
[INFO] [stdout] 245 |         let home = IpAddr::V4(127, 0, 0, 1);
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]    --> src/structs_enums.rs:246:13
[INFO] [stdout]     |
[INFO] [stdout] 246 |         let loopback = IpAddr::V6(String::from("::1"));
[INFO] [stdout]     |             ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `user2`
[INFO] [stdout]    --> src/structs_enums.rs:565:13
[INFO] [stdout]     |
[INFO] [stdout] 565 |         let user2 = User {
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_user2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/structs_enums.rs:605:19
[INFO] [stdout]     |
[INFO] [stdout] 605 |         let Point(x, y, z) = origin;
[INFO] [stdout]     |                   ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/structs_enums.rs:605:22
[INFO] [stdout]     |
[INFO] [stdout] 605 |         let Point(x, y, z) = origin;
[INFO] [stdout]     |                      ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]    --> src/structs_enums.rs:605:25
[INFO] [stdout]     |
[INFO] [stdout] 605 |         let Point(x, y, z) = origin;
[INFO] [stdout]     |                         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `subject`
[INFO] [stdout]    --> src/structs_enums.rs:624:13
[INFO] [stdout]     |
[INFO] [stdout] 624 |         let subject = AlwaysEqual;
[INFO] [stdout]     |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_subject`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v1`
[INFO] [stdout]    --> src/common_collections.rs:104:9
[INFO] [stdout]     |
[INFO] [stdout] 104 |     let v1: Vec<i32> = Vec::new();
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_v1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v2`
[INFO] [stdout]    --> src/common_collections.rs:107:9
[INFO] [stdout]     |
[INFO] [stdout] 107 |     let v2 = vec![1, 2, 69];
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_v2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `second_val`
[INFO] [stdout]    --> src/common_collections.rs:135:9
[INFO] [stdout]     |
[INFO] [stdout] 135 |     let second_val = &v_strings[1];
[INFO] [stdout]     |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_second_val`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error_handling.rs:26:12
[INFO] [stdout]    |
[INFO] [stdout] 26 |         Ok(f) => println!("Yay, file exists, we opened it"),
[INFO] [stdout]    |            ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/generics.rs:20:17
[INFO] [stdout]    |
[INFO] [stdout] 20 |             let x = 5;
[INFO] [stdout]    |                 ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]    --> src/generics.rs:138:13
[INFO] [stdout]     |
[INFO] [stdout] 138 |         let i = ImportantExcerpt {
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/generics.rs:195:13
[INFO] [stdout]     |
[INFO] [stdout] 195 |         let s: &'static str = "I have a static lifetime.";
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `integer`
[INFO] [stdout]    --> src/generics.rs:259:13
[INFO] [stdout]     |
[INFO] [stdout] 259 |         let integer = Point { x: 5, y: 10 };
[INFO] [stdout]     |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `float`
[INFO] [stdout]    --> src/generics.rs:260:13
[INFO] [stdout]     |
[INFO] [stdout] 260 |         let float = Point { x: 1.0, y: 4.0 };
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `mixed`
[INFO] [stdout]    --> src/generics.rs:261:13
[INFO] [stdout]     |
[INFO] [stdout] 261 |         let mixed = Point {x: 1.5, y: 69};
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_mixed`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/generics.rs:415:31
[INFO] [stdout]     |
[INFO] [stdout] 415 |         fn notify_mult_simple(item: &(impl Summary + Display))
[INFO] [stdout]     |                               ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/generics.rs:420:54
[INFO] [stdout]     |
[INFO] [stdout] 420 |         fn notify_mult_comples<T: Summary + Display>(item: &T)
[INFO] [stdout]     |                                                      ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/generics.rs:429:60
[INFO] [stdout]     |
[INFO] [stdout] 429 |         fn some_func<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                                            ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/generics.rs:429:67
[INFO] [stdout]     |
[INFO] [stdout] 429 |         fn some_func<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                                                   ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/generics.rs:435:34
[INFO] [stdout]     |
[INFO] [stdout] 435 |         fn some_func_where<T, U>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                  ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/generics.rs:435:41
[INFO] [stdout]     |
[INFO] [stdout] 435 |         fn some_func_where<T, U>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                         ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `query`
[INFO] [stdout]   --> src/minigrep.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let query = &args[QUERY_IDX];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_query`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `file_path`
[INFO] [stdout]   --> src/minigrep.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let file_path = &args[PATH_IDX];
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_file_path`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/iterators_closures.rs:307:9
[INFO] [stdout]     |
[INFO] [stdout] 307 |     let mut list = [
[INFO] [stdout]     |         ----^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/iterators_closures.rs:313:9
[INFO] [stdout]     |
[INFO] [stdout] 313 |     let mut sort_operations: Vec<String> = vec![];
[INFO] [stdout]     |         ----^^^^^^^^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/iterators_closures.rs:204:9
[INFO] [stdout]     |
[INFO] [stdout] 204 |     let s = example_closure(String::from("hello"));
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sort_operations`
[INFO] [stdout]    --> src/iterators_closures.rs:313:9
[INFO] [stdout]     |
[INFO] [stdout] 313 |     let mut sort_operations: Vec<String> = vec![];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_sort_operations`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `value`
[INFO] [stdout]    --> src/iterators_closures.rs:314:9
[INFO] [stdout]     |
[INFO] [stdout] 314 |     let value = String::from("closure called");
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_value`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lst`
[INFO] [stdout]    --> src/smart_pointers.rs:170:9
[INFO] [stdout]     |
[INFO] [stdout] 170 |     let lst = Cons(1, Box::new(Cons(2, Box::new(Cons(3, Box::new(Nil))))));
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_lst`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/main.rs:220:13
[INFO] [stdout]     |
[INFO] [stdout] 220 |         let s = "Hello, world!";
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:314:13
[INFO] [stdout]     |
[INFO] [stdout] 314 |         let mut s = String::from("some str");
[INFO] [stdout]     |             ----^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:459:13
[INFO] [stdout]     |
[INFO] [stdout] 459 |         let s2 = s1;
[INFO] [stdout]     |             ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `mut_str` is never read
[INFO] [stdout]    --> src/main.rs:481:27
[INFO] [stdout]     |
[INFO] [stdout] 481 |         let mut mut_str = String::from("This val will be dropped");
[INFO] [stdout]     |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this value is reassigned later and never used
[INFO] [stdout] 482 |         mut_str = String::from("This val will appear");
[INFO] [stdout]     |         ------- `mut_str` is overwritten here before the previous value is read
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:564:13
[INFO] [stdout]     |
[INFO] [stdout] 564 |         let x = 5;
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `y` is assigned to, but never used
[INFO] [stdout]    --> src/main.rs:568:13
[INFO] [stdout]     |
[INFO] [stdout] 568 |         let mut y = 68;
[INFO] [stdout]     |             ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: consider using `_y` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arr1`
[INFO] [stdout]    --> src/main.rs:651:13
[INFO] [stdout]     |
[INFO] [stdout] 651 |         let arr1: [i32; 5] = [1, 2, 3, 4, 5];        
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_arr1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/main.rs:674:13
[INFO] [stdout]     |
[INFO] [stdout] 674 |         let y = 69; // this is statement, does not return value
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `six`
[INFO] [stdout]    --> src/structs_enums.rs:134:9
[INFO] [stdout]     |
[INFO] [stdout] 134 |     let six = plus_one(five);
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_six`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/main.rs:681:13
[INFO] [stdout]     |
[INFO] [stdout] 681 |         let y = {
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `y` is never read
[INFO] [stdout]    --> src/main.rs:569:9
[INFO] [stdout]     |
[INFO] [stdout] 569 |         y = 69;
[INFO] [stdout]     |         ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0252`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `none`
[INFO] [stdout]    --> src/structs_enums.rs:135:9
[INFO] [stdout]     |
[INFO] [stdout] 135 |     let none = plus_one(None);
[INFO] [stdout]     |         ^^^^
[INFO] [stdout]     |
[INFO] [stdout] help: you might have meant to pattern match on the similarly named variant `None`
[INFO] [stdout]     |
[INFO] [stdout] 135 -     let none = plus_one(None);
[INFO] [stdout] 135 +     let std::prelude::v1::None = plus_one(None);
[INFO] [stdout]     |
[INFO] [stdout] help: if this is intentional, prefix it with an underscore
[INFO] [stdout]     |
[INFO] [stdout] 135 |     let _none = plus_one(None);
[INFO] [stdout]     |         +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `num_spaces`
[INFO] [stdout]    --> src/structs_enums.rs:160:20
[INFO] [stdout]     |
[INFO] [stdout] 160 |     fn move_player(num_spaces: u8) {}
[INFO] [stdout]     |                    ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_num_spaces`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_number`
[INFO] [stdout]    --> src/structs_enums.rs:182:9
[INFO] [stdout]     |
[INFO] [stdout] 182 |     let some_number = Some(5);
[INFO] [stdout]     |         ^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `some_char`
[INFO] [stdout]    --> src/structs_enums.rs:183:9
[INFO] [stdout]     |
[INFO] [stdout] 183 |     let some_char = Some('e');
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_some_char`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `absent_number`
[INFO] [stdout]    --> src/structs_enums.rs:187:9
[INFO] [stdout]     |
[INFO] [stdout] 187 |     let absent_number: Option<i32> = None;
[INFO] [stdout]     |         ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_absent_number`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_four`
[INFO] [stdout]    --> src/structs_enums.rs:211:13
[INFO] [stdout]     |
[INFO] [stdout] 211 |         let ip_four = IpAddrKind::V4;
[INFO] [stdout]     |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_four`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_six`
[INFO] [stdout]    --> src/structs_enums.rs:212:13
[INFO] [stdout]     |
[INFO] [stdout] 212 |         let ip_six = IpAddrKind::V6;
[INFO] [stdout]     |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_six`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `my_ip`
[INFO] [stdout]    --> src/structs_enums.rs:231:13
[INFO] [stdout]     |
[INFO] [stdout] 231 |         let my_ip = IpAddr::V4(String::from("127.0.0.1"));
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_my_ip`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `home`
[INFO] [stdout]    --> src/structs_enums.rs:245:13
[INFO] [stdout]     |
[INFO] [stdout] 245 |         let home = IpAddr::V4(127, 0, 0, 1);
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_home`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `loopback`
[INFO] [stdout]    --> src/structs_enums.rs:246:13
[INFO] [stdout]     |
[INFO] [stdout] 246 |         let loopback = IpAddr::V6(String::from("::1"));
[INFO] [stdout]     |             ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_loopback`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust_progr_lang_course` (bin "rust_progr_lang_course") due to 1 previous error; 59 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `user2`
[INFO] [stdout]    --> src/structs_enums.rs:565:13
[INFO] [stdout]     |
[INFO] [stdout] 565 |         let user2 = User {
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_user2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/structs_enums.rs:605:19
[INFO] [stdout]     |
[INFO] [stdout] 605 |         let Point(x, y, z) = origin;
[INFO] [stdout]     |                   ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/structs_enums.rs:605:22
[INFO] [stdout]     |
[INFO] [stdout] 605 |         let Point(x, y, z) = origin;
[INFO] [stdout]     |                      ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]    --> src/structs_enums.rs:605:25
[INFO] [stdout]     |
[INFO] [stdout] 605 |         let Point(x, y, z) = origin;
[INFO] [stdout]     |                         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `subject`
[INFO] [stdout]    --> src/structs_enums.rs:624:13
[INFO] [stdout]     |
[INFO] [stdout] 624 |         let subject = AlwaysEqual;
[INFO] [stdout]     |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_subject`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v1`
[INFO] [stdout]    --> src/common_collections.rs:104:9
[INFO] [stdout]     |
[INFO] [stdout] 104 |     let v1: Vec<i32> = Vec::new();
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_v1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v2`
[INFO] [stdout]    --> src/common_collections.rs:107:9
[INFO] [stdout]     |
[INFO] [stdout] 107 |     let v2 = vec![1, 2, 69];
[INFO] [stdout]     |         ^^ help: if this is intentional, prefix it with an underscore: `_v2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `second_val`
[INFO] [stdout]    --> src/common_collections.rs:135:9
[INFO] [stdout]     |
[INFO] [stdout] 135 |     let second_val = &v_strings[1];
[INFO] [stdout]     |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_second_val`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error_handling.rs:26:12
[INFO] [stdout]    |
[INFO] [stdout] 26 |         Ok(f) => println!("Yay, file exists, we opened it"),
[INFO] [stdout]    |            ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/generics.rs:20:17
[INFO] [stdout]    |
[INFO] [stdout] 20 |             let x = 5;
[INFO] [stdout]    |                 ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]    --> src/generics.rs:138:13
[INFO] [stdout]     |
[INFO] [stdout] 138 |         let i = ImportantExcerpt {
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/generics.rs:195:13
[INFO] [stdout]     |
[INFO] [stdout] 195 |         let s: &'static str = "I have a static lifetime.";
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `integer`
[INFO] [stdout]    --> src/generics.rs:259:13
[INFO] [stdout]     |
[INFO] [stdout] 259 |         let integer = Point { x: 5, y: 10 };
[INFO] [stdout]     |             ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `float`
[INFO] [stdout]    --> src/generics.rs:260:13
[INFO] [stdout]     |
[INFO] [stdout] 260 |         let float = Point { x: 1.0, y: 4.0 };
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `mixed`
[INFO] [stdout]    --> src/generics.rs:261:13
[INFO] [stdout]     |
[INFO] [stdout] 261 |         let mixed = Point {x: 1.5, y: 69};
[INFO] [stdout]     |             ^^^^^ help: if this is intentional, prefix it with an underscore: `_mixed`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/generics.rs:415:31
[INFO] [stdout]     |
[INFO] [stdout] 415 |         fn notify_mult_simple(item: &(impl Summary + Display))
[INFO] [stdout]     |                               ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item`
[INFO] [stdout]    --> src/generics.rs:420:54
[INFO] [stdout]     |
[INFO] [stdout] 420 |         fn notify_mult_comples<T: Summary + Display>(item: &T)
[INFO] [stdout]     |                                                      ^^^^ help: if this is intentional, prefix it with an underscore: `_item`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/generics.rs:429:60
[INFO] [stdout]     |
[INFO] [stdout] 429 |         fn some_func<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                                            ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/generics.rs:429:67
[INFO] [stdout]     |
[INFO] [stdout] 429 |         fn some_func<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                                                   ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]    --> src/generics.rs:435:34
[INFO] [stdout]     |
[INFO] [stdout] 435 |         fn some_func_where<T, U>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                  ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `u`
[INFO] [stdout]    --> src/generics.rs:435:41
[INFO] [stdout]     |
[INFO] [stdout] 435 |         fn some_func_where<T, U>(t: &T, u: &U) -> i32
[INFO] [stdout]     |                                         ^ help: if this is intentional, prefix it with an underscore: `_u`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `query`
[INFO] [stdout]   --> src/minigrep.rs:20:9
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let query = &args[QUERY_IDX];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_query`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `file_path`
[INFO] [stdout]   --> src/minigrep.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let file_path = &args[PATH_IDX];
[INFO] [stdout]    |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_file_path`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/iterators_closures.rs:307:9
[INFO] [stdout]     |
[INFO] [stdout] 307 |     let mut list = [
[INFO] [stdout]     |         ----^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/iterators_closures.rs:313:9
[INFO] [stdout]     |
[INFO] [stdout] 313 |     let mut sort_operations: Vec<String> = vec![];
[INFO] [stdout]     |         ----^^^^^^^^^^^^^^^
[INFO] [stdout]     |         |
[INFO] [stdout]     |         help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/iterators_closures.rs:204:9
[INFO] [stdout]     |
[INFO] [stdout] 204 |     let s = example_closure(String::from("hello"));
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sort_operations`
[INFO] [stdout]    --> src/iterators_closures.rs:313:9
[INFO] [stdout]     |
[INFO] [stdout] 313 |     let mut sort_operations: Vec<String> = vec![];
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_sort_operations`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `value`
[INFO] [stdout]    --> src/iterators_closures.rs:314:9
[INFO] [stdout]     |
[INFO] [stdout] 314 |     let value = String::from("closure called");
[INFO] [stdout]     |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_value`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lst`
[INFO] [stdout]    --> src/smart_pointers.rs:170:9
[INFO] [stdout]     |
[INFO] [stdout] 170 |     let lst = Cons(1, Box::new(Cons(2, Box::new(Cons(3, Box::new(Nil))))));
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_lst`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]    --> src/main.rs:220:13
[INFO] [stdout]     |
[INFO] [stdout] 220 |         let s = "Hello, world!";
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:314:13
[INFO] [stdout]     |
[INFO] [stdout] 314 |         let mut s = String::from("some str");
[INFO] [stdout]     |             ----^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]    --> src/main.rs:459:13
[INFO] [stdout]     |
[INFO] [stdout] 459 |         let s2 = s1;
[INFO] [stdout]     |             ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `mut_str` is never read
[INFO] [stdout]    --> src/main.rs:481:27
[INFO] [stdout]     |
[INFO] [stdout] 481 |         let mut mut_str = String::from("This val will be dropped");
[INFO] [stdout]     |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this value is reassigned later and never used
[INFO] [stdout] 482 |         mut_str = String::from("This val will appear");
[INFO] [stdout]     |         ------- `mut_str` is overwritten here before the previous value is read
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_assignments)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:564:13
[INFO] [stdout]     |
[INFO] [stdout] 564 |         let x = 5;
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `y` is assigned to, but never used
[INFO] [stdout]    --> src/main.rs:568:13
[INFO] [stdout]     |
[INFO] [stdout] 568 |         let mut y = 68;
[INFO] [stdout]     |             ^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: consider using `_y` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arr1`
[INFO] [stdout]    --> src/main.rs:651:13
[INFO] [stdout]     |
[INFO] [stdout] 651 |         let arr1: [i32; 5] = [1, 2, 3, 4, 5];        
[INFO] [stdout]     |             ^^^^ help: if this is intentional, prefix it with an underscore: `_arr1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/main.rs:674:13
[INFO] [stdout]     |
[INFO] [stdout] 674 |         let y = 69; // this is statement, does not return value
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]    --> src/main.rs:681:13
[INFO] [stdout]     |
[INFO] [stdout] 681 |         let y = {
[INFO] [stdout]     |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `y` is never read
[INFO] [stdout]    --> src/main.rs:569:9
[INFO] [stdout]     |
[INFO] [stdout] 569 |         y = 69;
[INFO] [stdout]     |         ^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0252`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust_progr_lang_course` (bin "rust_progr_lang_course" test) due to 1 previous error; 59 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2", kill_on_drop: false }`
[INFO] [stdout] 8b8df485ea2d1e8e792c4efa35a5cd5b7d0381dcbb0b049963f8c725e3f987b2
