[INFO] cloning repository https://github.com/harismuzaffer/rustsnippets
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/harismuzaffer/rustsnippets" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fharismuzaffer%2Frustsnippets", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fharismuzaffer%2Frustsnippets'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e3ba808227cac87b3b252456d8c11d914e4ce61b
[INFO] checking harismuzaffer/rustsnippets against master#3129d37ef7075ee3cbaa3d6cbe1b5794f67192b0 for pr-143164
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fharismuzaffer%2Frustsnippets" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/harismuzaffer/rustsnippets
[INFO] finished tweaking git repo https://github.com/harismuzaffer/rustsnippets
[INFO] tweaked toml for git repo https://github.com/harismuzaffer/rustsnippets written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/harismuzaffer/rustsnippets on toolchain 3129d37ef7075ee3cbaa3d6cbe1b5794f67192b0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+3129d37ef7075ee3cbaa3d6cbe1b5794f67192b0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/harismuzaffer/rustsnippets 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" "+3129d37ef7075ee3cbaa3d6cbe1b5794f67192b0" "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-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+3129d37ef7075ee3cbaa3d6cbe1b5794f67192b0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] dffcbab3e6057b22ef8196e67c8db8130693f6e4c839698ac7e432908bf79495
[INFO] running `Command { std: "docker" "start" "-a" "dffcbab3e6057b22ef8196e67c8db8130693f6e4c839698ac7e432908bf79495", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "dffcbab3e6057b22ef8196e67c8db8130693f6e4c839698ac7e432908bf79495", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dffcbab3e6057b22ef8196e67c8db8130693f6e4c839698ac7e432908bf79495", kill_on_drop: false }`
[INFO] [stdout] dffcbab3e6057b22ef8196e67c8db8130693f6e4c839698ac7e432908bf79495
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+3129d37ef7075ee3cbaa3d6cbe1b5794f67192b0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] cea25665bd66aecfccf24e8d240b0afe142de3cbefe5e0bd1dd1fb7044cf804e
[INFO] running `Command { std: "docker" "start" "-a" "cea25665bd66aecfccf24e8d240b0afe142de3cbefe5e0bd1dd1fb7044cf804e", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.77
[INFO] [stderr]     Checking rand_core v0.4.2
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking rand v0.5.6
[INFO] [stderr]     Checking learningrust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0433]: failed to resolve: use of unresolved module or unlinked crate `slice`
[INFO] [stdout]   --> src/main.rs:88:13
[INFO] [stdout]    |
[INFO] [stdout] 88 |             slice::from_raw_parts_mut(ptr, mid),
[INFO] [stdout]    |             ^^^^^ use of unresolved module or unlinked crate `slice`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `slice`, use `cargo add slice` to add it to your `Cargo.toml`
[INFO] [stdout] help: consider importing this module
[INFO] [stdout]    |
[INFO] [stdout] 1  + use std::slice;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of unresolved module or unlinked crate `slice`
[INFO] [stdout]   --> src/main.rs:89:13
[INFO] [stdout]    |
[INFO] [stdout] 89 |             slice::from_raw_parts_mut(ptr.add(mid), len - mid),
[INFO] [stdout]    |             ^^^^^ use of unresolved module or unlinked crate `slice`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `slice`, use `cargo add slice` to add it to your `Cargo.toml`
[INFO] [stdout] help: consider importing this module
[INFO] [stdout]    |
[INFO] [stdout] 1  + use std::slice;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around assigned value
[INFO] [stdout]  --> src/expressions.rs:5:17
[INFO] [stdout]   |
[INFO] [stdout] 5 |         let a = (78 - 10); 
[INFO] [stdout]   |                 ^       ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]   |
[INFO] [stdout] 5 -         let a = (78 - 10); 
[INFO] [stdout] 5 +         let a = 78 - 10; 
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around assigned value
[INFO] [stdout]   --> src/expressions.rs:10:17
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let a = (56 * 2); // a statemnt
[INFO] [stdout]    |                 ^      ^
[INFO] [stdout]    |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout] 10 -         let a = (56 * 2); // a statemnt
[INFO] [stdout] 10 +         let a = 56 * 2; // a statemnt
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of unresolved module or unlinked crate `slice`
[INFO] [stdout]   --> src/main.rs:88:13
[INFO] [stdout]    |
[INFO] [stdout] 88 |             slice::from_raw_parts_mut(ptr, mid),
[INFO] [stdout]    |             ^^^^^ use of unresolved module or unlinked crate `slice`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `slice`, use `cargo add slice` to add it to your `Cargo.toml`
[INFO] [stdout] help: consider importing this module
[INFO] [stdout]    |
[INFO] [stdout] 1  + use std::slice;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of unresolved module or unlinked crate `slice`
[INFO] [stdout]   --> src/main.rs:89:13
[INFO] [stdout]    |
[INFO] [stdout] 89 |             slice::from_raw_parts_mut(ptr.add(mid), len - mid),
[INFO] [stdout]    |             ^^^^^ use of unresolved module or unlinked crate `slice`
[INFO] [stdout]    |
[INFO] [stdout]    = help: if you wanted to use a crate named `slice`, use `cargo add slice` to add it to your `Cargo.toml`
[INFO] [stdout] help: consider importing this module
[INFO] [stdout]    |
[INFO] [stdout] 1  + use std::slice;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around assigned value
[INFO] [stdout]  --> src/expressions.rs:5:17
[INFO] [stdout]   |
[INFO] [stdout] 5 |         let a = (78 - 10); 
[INFO] [stdout]   |                 ^       ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]   |
[INFO] [stdout] 5 -         let a = (78 - 10); 
[INFO] [stdout] 5 +         let a = 78 - 10; 
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around assigned value
[INFO] [stdout]   --> src/expressions.rs:10:17
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let a = (56 * 2); // a statemnt
[INFO] [stdout]    |                 ^      ^
[INFO] [stdout]    |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]    |
[INFO] [stdout] 10 -         let a = (56 * 2); // a statemnt
[INFO] [stdout] 10 +         let a = 56 * 2; // a statemnt
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]  --> src/strings.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let b = a; // this doesnt move ownership from a to b becoz a is a string literal
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/strings.rs:11:9
[INFO] [stdout]    |
[INFO] [stdout] 11 |     let s = "hello world"; // a string slice
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ss`
[INFO] [stdout]   --> src/strings.rs:15:9
[INFO] [stdout]    |
[INFO] [stdout] 15 |     let ss = &s[..];
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_ss`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `another_slice_string`
[INFO] [stdout]   --> src/strings.rs:28:9
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let another_slice_string = &normal_string[0..5];
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_another_slice_string`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/datatypes.rs:21:17
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let (x, y, z, o) = tup;
[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/datatypes.rs:21:20
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let (x, y, z, o) = tup;
[INFO] [stdout]    |                    ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `o`
[INFO] [stdout]   --> src/datatypes.rs:21:23
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let (x, y, z, o) = tup;
[INFO] [stdout]    |                       ^ help: if this is intentional, prefix it with an underscore: `_o`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `x` is never read
[INFO] [stdout]   --> src/enums.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 24 |     x = get_location(myipadd);
[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: `b`
[INFO] [stdout]  --> src/strings.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 |     let b = a; // this doesnt move ownership from a to b becoz a is a string literal
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/strings.rs:11:9
[INFO] [stdout]    |
[INFO] [stdout] 11 |     let s = "hello world"; // a string slice
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ss`
[INFO] [stdout]   --> src/strings.rs:15:9
[INFO] [stdout]    |
[INFO] [stdout] 15 |     let ss = &s[..];
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_ss`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `another_slice_string`
[INFO] [stdout]   --> src/strings.rs:28:9
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let another_slice_string = &normal_string[0..5];
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_another_slice_string`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/vectors.rs:9:13
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let mut v: Vec<u32> = Vec::new(); // an empty vector
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/vectors.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let mut v: Vec<u32> = Vec::new(); // an empty vector
[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: unused variable: `row`
[INFO] [stdout]   --> src/vectors.rs:41:13
[INFO] [stdout]    |
[INFO] [stdout] 41 |         let row = vec![
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_row`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/datatypes.rs:21:17
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let (x, y, z, o) = tup;
[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/datatypes.rs:21:20
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let (x, y, z, o) = tup;
[INFO] [stdout]    |                    ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `o`
[INFO] [stdout]   --> src/datatypes.rs:21:23
[INFO] [stdout]    |
[INFO] [stdout] 21 |         let (x, y, z, o) = tup;
[INFO] [stdout]    |                       ^ help: if this is intentional, prefix it with an underscore: `_o`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/safety_rules.rs:23:14
[INFO] [stdout]    |
[INFO] [stdout] 23 |     fn ownit(s: String){
[INFO] [stdout]    |              ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `kk`
[INFO] [stdout]   --> src/safety_rules.rs:39:13
[INFO] [stdout]    |
[INFO] [stdout] 39 |         let kk = &k; // ok
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_kk`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `kkk`
[INFO] [stdout]   --> src/safety_rules.rs:40:13
[INFO] [stdout]    |
[INFO] [stdout] 40 |         let kkk = &mut k; // NOT OK(as long as `kk` is active i.e. if we attempt to use `kk` later) 
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_kkk`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ll`
[INFO] [stdout]   --> src/safety_rules.rs:50:13
[INFO] [stdout]    |
[INFO] [stdout] 50 |         let ll = &mut l; // ok
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_ll`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lll`
[INFO] [stdout]   --> src/safety_rules.rs:51:13
[INFO] [stdout]    |
[INFO] [stdout] 51 |         let lll = &mut l; // NOT OK(as long as `ll` is active) because two immutable references, next line is an error
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_lll`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `m`
[INFO] [stdout]   --> src/safety_rules.rs:55:17
[INFO] [stdout]    |
[INFO] [stdout] 55 |         let mut m = String::from("hello world");
[INFO] [stdout]    |                 ^ help: if this is intentional, prefix it with an underscore: `_m`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `x` is never read
[INFO] [stdout]   --> src/enums.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 24 |     x = get_location(myipadd);
[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: variable does not need to be mutable
[INFO] [stdout]   --> src/safety_rules.rs:55:13
[INFO] [stdout]    |
[INFO] [stdout] 55 |         let mut m = String::from("hello world");
[INFO] [stdout]    |             ----^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]  --> src/vectors.rs:9:13
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let mut v: Vec<u32> = Vec::new(); // an empty vector
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]  --> src/vectors.rs:9:9
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let mut v: Vec<u32> = Vec::new(); // an empty vector
[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: unused variable: `row`
[INFO] [stdout]   --> src/vectors.rs:41:13
[INFO] [stdout]    |
[INFO] [stdout] 41 |         let row = vec![
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_row`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/safety_rules.rs:23:14
[INFO] [stdout]    |
[INFO] [stdout] 23 |     fn ownit(s: String){
[INFO] [stdout]    |              ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `kk`
[INFO] [stdout]   --> src/safety_rules.rs:39:13
[INFO] [stdout]    |
[INFO] [stdout] 39 |         let kk = &k; // ok
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_kk`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `kkk`
[INFO] [stdout]   --> src/safety_rules.rs:40:13
[INFO] [stdout]    |
[INFO] [stdout] 40 |         let kkk = &mut k; // NOT OK(as long as `kk` is active i.e. if we attempt to use `kk` later) 
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_kkk`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ll`
[INFO] [stdout]   --> src/safety_rules.rs:50:13
[INFO] [stdout]    |
[INFO] [stdout] 50 |         let ll = &mut l; // ok
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_ll`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `lll`
[INFO] [stdout]   --> src/safety_rules.rs:51:13
[INFO] [stdout]    |
[INFO] [stdout] 51 |         let lll = &mut l; // NOT OK(as long as `ll` is active) because two immutable references, next line is an error
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_lll`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `m`
[INFO] [stdout]   --> src/safety_rules.rs:55:17
[INFO] [stdout]    |
[INFO] [stdout] 55 |         let mut m = String::from("hello world");
[INFO] [stdout]    |                 ^ help: if this is intentional, prefix it with an underscore: `_m`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `item_100th`
[INFO] [stdout]  --> src/error_handling.rs:6:13
[INFO] [stdout]   |
[INFO] [stdout] 6 |         let item_100th = &v[99];
[INFO] [stdout]   |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_item_100th`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error_handling.rs:25:13
[INFO] [stdout]    |
[INFO] [stdout] 25 |         let f = match f {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `abc`
[INFO] [stdout]   --> src/error_handling.rs:35:17
[INFO] [stdout]    |
[INFO] [stdout] 35 |                 abc => panic!("problem opening the file")
[INFO] [stdout]    |                 ^^^ help: if this is intentional, prefix it with an underscore: `_abc`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error_handling.rs:42:13
[INFO] [stdout]    |
[INFO] [stdout] 42 |         let f = match f {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ff`
[INFO] [stdout]   --> src/error_handling.rs:49:13
[INFO] [stdout]    |
[INFO] [stdout] 49 |         let ff = File::open("somefile.csv").expect("file could not be opened");
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_ff`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `fff`
[INFO] [stdout]   --> src/error_handling.rs:50:13
[INFO] [stdout]    |
[INFO] [stdout] 50 |         let fff = File::open("somefile.csv").unwrap();
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_fff`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/safety_rules.rs:55:13
[INFO] [stdout]    |
[INFO] [stdout] 55 |         let mut m = String::from("hello world");
[INFO] [stdout]    |             ----^
[INFO] [stdout]    |             |
[INFO] [stdout]    |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `r` is assigned to, but never used
[INFO] [stdout]  --> src/lifetimes.rs:2:9
[INFO] [stdout]   |
[INFO] [stdout] 2 |     let r;
[INFO] [stdout]   |         ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_r` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `r` is never read
[INFO] [stdout]  --> src/lifetimes.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |         r = &s;
[INFO] [stdout]   |         ^
[INFO] [stdout]   |
[INFO] [stdout]   = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `result` is assigned to, but never used
[INFO] [stdout]   --> src/lifetimes.rs:60:17
[INFO] [stdout]    |
[INFO] [stdout] 60 |             let result;
[INFO] [stdout]    |                 ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_result` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `result` is never read
[INFO] [stdout]   --> src/lifetimes.rs:75:17
[INFO] [stdout]    |
[INFO] [stdout] 75 |                 result = longest(string1.as_str(), string2.as_str());
[INFO] [stdout]    |                 ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/lifetimes.rs:157:42
[INFO] [stdout]     |
[INFO] [stdout] 157 |             fn lifetime_mismatch<'a, 'b>(x: &'a i32, y: &'b i32) -> &'a i32 {
[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/lifetimes.rs:157:54
[INFO] [stdout]     |
[INFO] [stdout] 157 |             fn lifetime_mismatch<'a, 'b>(x: &'a i32, y: &'b i32) -> &'a i32 {
[INFO] [stdout]     |                                                      ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/lifetimes.rs:166:36
[INFO] [stdout]     |
[INFO] [stdout] 166 |             fn static_lifetime<'a>(x: &'a i32) -> &'static i32 {
[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/lifetimes.rs:235:13
[INFO] [stdout]     |
[INFO] [stdout] 235 |         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: `item_100th`
[INFO] [stdout]  --> src/error_handling.rs:6:13
[INFO] [stdout]   |
[INFO] [stdout] 6 |         let item_100th = &v[99];
[INFO] [stdout]   |             ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_item_100th`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> src/closures_iterators.rs:15:13
[INFO] [stdout]    |
[INFO] [stdout] 15 |         let y = String::from("world");
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error_handling.rs:25:13
[INFO] [stdout]    |
[INFO] [stdout] 25 |         let f = match f {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `abc`
[INFO] [stdout]   --> src/error_handling.rs:35:17
[INFO] [stdout]    |
[INFO] [stdout] 35 |                 abc => panic!("problem opening the file")
[INFO] [stdout]    |                 ^^^ help: if this is intentional, prefix it with an underscore: `_abc`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v3`
[INFO] [stdout]   --> src/closures_iterators.rs:70:17
[INFO] [stdout]    |
[INFO] [stdout] 70 |             let v3: Vec<&mut String> = v2.map(|x| {
[INFO] [stdout]    |                 ^^ help: if this is intentional, prefix it with an underscore: `_v3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> src/error_handling.rs:42:13
[INFO] [stdout]    |
[INFO] [stdout] 42 |         let f = match f {
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ff`
[INFO] [stdout]   --> src/error_handling.rs:49:13
[INFO] [stdout]    |
[INFO] [stdout] 49 |         let ff = File::open("somefile.csv").expect("file could not be opened");
[INFO] [stdout]    |             ^^ help: if this is intentional, prefix it with an underscore: `_ff`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `fff`
[INFO] [stdout]   --> src/error_handling.rs:50:13
[INFO] [stdout]    |
[INFO] [stdout] 50 |         let fff = File::open("somefile.csv").unwrap();
[INFO] [stdout]    |             ^^^ help: if this is intentional, prefix it with an underscore: `_fff`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `r` is assigned to, but never used
[INFO] [stdout]  --> src/lifetimes.rs:2:9
[INFO] [stdout]   |
[INFO] [stdout] 2 |     let r;
[INFO] [stdout]   |         ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_r` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `r` is never read
[INFO] [stdout]  --> src/lifetimes.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |         r = &s;
[INFO] [stdout]   |         ^
[INFO] [stdout]   |
[INFO] [stdout]   = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]  --> src/expressions.rs:5:13
[INFO] [stdout]   |
[INFO] [stdout] 5 |         let a = (78 - 10); 
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/expressions.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let a = (56 * 2); // a statemnt
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `result` is assigned to, but never used
[INFO] [stdout]   --> src/lifetimes.rs:60:17
[INFO] [stdout]    |
[INFO] [stdout] 60 |             let result;
[INFO] [stdout]    |                 ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_result` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `result` is never read
[INFO] [stdout]   --> src/lifetimes.rs:75:17
[INFO] [stdout]    |
[INFO] [stdout] 75 |                 result = longest(string1.as_str(), string2.as_str());
[INFO] [stdout]    |                 ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/lifetimes.rs:157:42
[INFO] [stdout]     |
[INFO] [stdout] 157 |             fn lifetime_mismatch<'a, 'b>(x: &'a i32, y: &'b i32) -> &'a i32 {
[INFO] [stdout]     |                                          ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/expressions.rs:36:13
[INFO] [stdout]    |
[INFO] [stdout] 36 |         let x = some_fn(); // x holds 10
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/stack_vs_heap.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let b = a; // since `a` implements Copy trait, the data that `a` is holding(on the Stack) is
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ss`
[INFO] [stdout]   --> src/stack_vs_heap.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let ss = s; // since `s` DOES NOT implement Copy trait, `ss` gets a copy of `s` but only the 
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_ss`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `vvv`
[INFO] [stdout]   --> src/main.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let vvv = vv.filter(|x| **x > xx);
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_vvv`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `vvv`
[INFO] [stdout]   --> src/main.rs:56:9
[INFO] [stdout]    |
[INFO] [stdout] 56 |     let vvv: Vec<i32> = vv.map(|x| x + 100).collect();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_vvv`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:61:9
[INFO] [stdout]    |
[INFO] [stdout] 61 |     let x = it1.any(|&x| x > 1);
[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/lifetimes.rs:157:54
[INFO] [stdout]     |
[INFO] [stdout] 157 |             fn lifetime_mismatch<'a, 'b>(x: &'a i32, y: &'b i32) -> &'a i32 {
[INFO] [stdout]     |                                                      ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/lifetimes.rs:166:36
[INFO] [stdout]     |
[INFO] [stdout] 166 |             fn static_lifetime<'a>(x: &'a i32) -> &'static i32 {
[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/lifetimes.rs:235:13
[INFO] [stdout]     |
[INFO] [stdout] 235 |         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: `y`
[INFO] [stdout]   --> src/closures_iterators.rs:15:13
[INFO] [stdout]    |
[INFO] [stdout] 15 |         let y = String::from("world");
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v3`
[INFO] [stdout]   --> src/closures_iterators.rs:70:17
[INFO] [stdout]    |
[INFO] [stdout] 70 |             let v3: Vec<&mut String> = v2.map(|x| {
[INFO] [stdout]    |                 ^^ help: if this is intentional, prefix it with an underscore: `_v3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0433`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]  --> src/expressions.rs:5:13
[INFO] [stdout]   |
[INFO] [stdout] 5 |         let a = (78 - 10); 
[INFO] [stdout]   |             ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/expressions.rs:10:13
[INFO] [stdout]    |
[INFO] [stdout] 10 |         let a = (56 * 2); // a statemnt
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/expressions.rs:36:13
[INFO] [stdout]    |
[INFO] [stdout] 36 |         let x = some_fn(); // x holds 10
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/stack_vs_heap.rs:19:9
[INFO] [stdout]    |
[INFO] [stdout] 19 |     let b = a; // since `a` implements Copy trait, the data that `a` is holding(on the Stack) is
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ss`
[INFO] [stdout]   --> src/stack_vs_heap.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let ss = s; // since `s` DOES NOT implement Copy trait, `ss` gets a copy of `s` but only the 
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_ss`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `vvv`
[INFO] [stdout]   --> src/main.rs:49:9
[INFO] [stdout]    |
[INFO] [stdout] 49 |     let vvv = vv.filter(|x| **x > xx);
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_vvv`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `vvv`
[INFO] [stdout]   --> src/main.rs:56:9
[INFO] [stdout]    |
[INFO] [stdout] 56 |     let vvv: Vec<i32> = vv.map(|x| x + 100).collect();
[INFO] [stdout]    |         ^^^ help: if this is intentional, prefix it with an underscore: `_vvv`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:61:9
[INFO] [stdout]    |
[INFO] [stdout] 61 |     let x = it1.any(|&x| x > 1);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `learningrust` (bin "learningrust") due to 2 previous errors; 44 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] For more information about this error, try `rustc --explain E0433`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `learningrust` (bin "learningrust" test) due to 2 previous errors; 44 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "cea25665bd66aecfccf24e8d240b0afe142de3cbefe5e0bd1dd1fb7044cf804e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cea25665bd66aecfccf24e8d240b0afe142de3cbefe5e0bd1dd1fb7044cf804e", kill_on_drop: false }`
[INFO] [stdout] cea25665bd66aecfccf24e8d240b0afe142de3cbefe5e0bd1dd1fb7044cf804e
