[INFO] cloning repository https://github.com/sagaban/rust-by-example
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sagaban/rust-by-example" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsagaban%2Frust-by-example", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsagaban%2Frust-by-example'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 2d7f259cdc0f6ca066acfa22d49b7a66667afd24
[INFO] testing sagaban/rust-by-example against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsagaban%2Frust-by-example" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sagaban/rust-by-example on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sagaban/rust-by-example
[INFO] finished tweaking git repo https://github.com/sagaban/rust-by-example
[INFO] tweaked toml for git repo https://github.com/sagaban/rust-by-example written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/sagaban/rust-by-example already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 221c75e104356e9608f5bc4c580b3a5aa4feefd5cf70a4cbb9ae451ffd819378
[INFO] running `Command { std: "docker" "start" "-a" "221c75e104356e9608f5bc4c580b3a5aa4feefd5cf70a4cbb9ae451ffd819378", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "221c75e104356e9608f5bc4c580b3a5aa4feefd5cf70a4cbb9ae451ffd819378", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "221c75e104356e9608f5bc4c580b3a5aa4feefd5cf70a4cbb9ae451ffd819378", kill_on_drop: false }`
[INFO] [stdout] 221c75e104356e9608f5bc4c580b3a5aa4feefd5cf70a4cbb9ae451ffd819378
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f48e147b948063d488322d42fea199e0f96f6dbe618faa4bc6b6924565869d44
[INFO] running `Command { std: "docker" "start" "-a" "f48e147b948063d488322d42fea199e0f96f6dbe618faa4bc6b6924565869d44", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust-by-example v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `logical`
[INFO] [stdout]   --> src/chapters/c02.rs:25:7
[INFO] [stdout]    |
[INFO] [stdout] 25 |   let logical: bool = true;
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_logical`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a_float`
[INFO] [stdout]   --> src/chapters/c02.rs:27:7
[INFO] [stdout]    |
[INFO] [stdout] 27 |   let a_float: f64 = 1.0; // Regular annotation
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_a_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `an_integer`
[INFO] [stdout]   --> src/chapters/c02.rs:28:7
[INFO] [stdout]    |
[INFO] [stdout] 28 |   let an_integer = 5i32; // Suffix annotation
[INFO] [stdout]    |       ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_an_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `default_float`
[INFO] [stdout]   --> src/chapters/c02.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 |   let default_float = 3.0; // `f64`
[INFO] [stdout]    |       ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `default_integer`
[INFO] [stdout]   --> src/chapters/c02.rs:32:7
[INFO] [stdout]    |
[INFO] [stdout] 32 |   let default_integer = 7; // `i32`
[INFO] [stdout]    |       ^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `inferred_type` is assigned to, but never used
[INFO] [stdout]   --> src/chapters/c02.rs:35:11
[INFO] [stdout]    |
[INFO] [stdout] 35 |   let mut inferred_type = 12; // Type i64 is inferred from another line
[INFO] [stdout]    |           ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_inferred_type` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `inferred_type` is never read
[INFO] [stdout]   --> src/chapters/c02.rs:36:3
[INFO] [stdout]    |
[INFO] [stdout] 36 |   inferred_type = 4294967296i64;
[INFO] [stdout]    |   ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `mutable` is assigned to, but never used
[INFO] [stdout]   --> src/chapters/c02.rs:39:11
[INFO] [stdout]    |
[INFO] [stdout] 39 |   let mut mutable = 12; // Mutable `i32`
[INFO] [stdout]    |           ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_mutable` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `mutable` is never read
[INFO] [stdout]   --> src/chapters/c02.rs:40:3
[INFO] [stdout]    |
[INFO] [stdout] 40 |   mutable = 21;
[INFO] [stdout]    |   ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `mutable`
[INFO] [stdout]   --> src/chapters/c02.rs:46:7
[INFO] [stdout]    |
[INFO] [stdout] 46 |   let mutable = true;
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_mutable`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Subtract`
[INFO] [stdout]    --> src/chapters/c03.rs:220:5
[INFO] [stdout]     |
[INFO] [stdout] 220 |     Subtract,
[INFO] [stdout]     |     ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `c_liKe_enums` should have a snake case name
[INFO] [stdout]    --> src/chapters/c03.rs:281:8
[INFO] [stdout]     |
[INFO] [stdout] 281 | pub fn c_liKe_enums() {
[INFO] [stdout]     |        ^^^^^^^^^^^^ help: convert the identifier to snake case: `c_li_ke_enums`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 12 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.96s
[INFO] running `Command { std: "docker" "inspect" "f48e147b948063d488322d42fea199e0f96f6dbe618faa4bc6b6924565869d44", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f48e147b948063d488322d42fea199e0f96f6dbe618faa4bc6b6924565869d44", kill_on_drop: false }`
[INFO] [stdout] f48e147b948063d488322d42fea199e0f96f6dbe618faa4bc6b6924565869d44
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 05b62f8a1309538c4327a029b6b2ccaf811be16a247e501ff86870bd535e919d
[INFO] running `Command { std: "docker" "start" "-a" "05b62f8a1309538c4327a029b6b2ccaf811be16a247e501ff86870bd535e919d", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling rust-by-example v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `logical`
[INFO] [stdout]   --> src/chapters/c02.rs:25:7
[INFO] [stdout]    |
[INFO] [stdout] 25 |   let logical: bool = true;
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_logical`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a_float`
[INFO] [stdout]   --> src/chapters/c02.rs:27:7
[INFO] [stdout]    |
[INFO] [stdout] 27 |   let a_float: f64 = 1.0; // Regular annotation
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_a_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `an_integer`
[INFO] [stdout]   --> src/chapters/c02.rs:28:7
[INFO] [stdout]    |
[INFO] [stdout] 28 |   let an_integer = 5i32; // Suffix annotation
[INFO] [stdout]    |       ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_an_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `default_float`
[INFO] [stdout]   --> src/chapters/c02.rs:31:7
[INFO] [stdout]    |
[INFO] [stdout] 31 |   let default_float = 3.0; // `f64`
[INFO] [stdout]    |       ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_float`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `default_integer`
[INFO] [stdout]   --> src/chapters/c02.rs:32:7
[INFO] [stdout]    |
[INFO] [stdout] 32 |   let default_integer = 7; // `i32`
[INFO] [stdout]    |       ^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_integer`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `inferred_type` is assigned to, but never used
[INFO] [stdout]   --> src/chapters/c02.rs:35:11
[INFO] [stdout]    |
[INFO] [stdout] 35 |   let mut inferred_type = 12; // Type i64 is inferred from another line
[INFO] [stdout]    |           ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_inferred_type` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `inferred_type` is never read
[INFO] [stdout]   --> src/chapters/c02.rs:36:3
[INFO] [stdout]    |
[INFO] [stdout] 36 |   inferred_type = 4294967296i64;
[INFO] [stdout]    |   ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `mutable` is assigned to, but never used
[INFO] [stdout]   --> src/chapters/c02.rs:39:11
[INFO] [stdout]    |
[INFO] [stdout] 39 |   let mut mutable = 12; // Mutable `i32`
[INFO] [stdout]    |           ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: consider using `_mutable` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `mutable` is never read
[INFO] [stdout]   --> src/chapters/c02.rs:40:3
[INFO] [stdout]    |
[INFO] [stdout] 40 |   mutable = 21;
[INFO] [stdout]    |   ^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `mutable`
[INFO] [stdout]   --> src/chapters/c02.rs:46:7
[INFO] [stdout]    |
[INFO] [stdout] 46 |   let mutable = true;
[INFO] [stdout]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_mutable`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant is never constructed: `Subtract`
[INFO] [stdout]    --> src/chapters/c03.rs:220:5
[INFO] [stdout]     |
[INFO] [stdout] 220 |     Subtract,
[INFO] [stdout]     |     ^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `c_liKe_enums` should have a snake case name
[INFO] [stdout]    --> src/chapters/c03.rs:281:8
[INFO] [stdout]     |
[INFO] [stdout] 281 | pub fn c_liKe_enums() {
[INFO] [stdout]     |        ^^^^^^^^^^^^ help: convert the identifier to snake case: `c_li_ke_enums`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 12 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 2.49s
[INFO] running `Command { std: "docker" "inspect" "05b62f8a1309538c4327a029b6b2ccaf811be16a247e501ff86870bd535e919d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "05b62f8a1309538c4327a029b6b2ccaf811be16a247e501ff86870bd535e919d", kill_on_drop: false }`
[INFO] [stdout] 05b62f8a1309538c4327a029b6b2ccaf811be16a247e501ff86870bd535e919d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 16004f7bab51d665d0898505d3a5f0bc0693f48ebb9388e41af8976b1954d374
[INFO] running `Command { std: "docker" "start" "-a" "16004f7bab51d665d0898505d3a5f0bc0693f48ebb9388e41af8976b1954d374", kill_on_drop: false }`
[INFO] [stderr] warning: unused variable: `logical`
[INFO] [stderr]   --> src/chapters/c02.rs:25:7
[INFO] [stderr]    |
[INFO] [stderr] 25 |   let logical: bool = true;
[INFO] [stderr]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_logical`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `a_float`
[INFO] [stderr]   --> src/chapters/c02.rs:27:7
[INFO] [stderr]    |
[INFO] [stderr] 27 |   let a_float: f64 = 1.0; // Regular annotation
[INFO] [stderr]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_a_float`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `an_integer`
[INFO] [stderr]   --> src/chapters/c02.rs:28:7
[INFO] [stderr]    |
[INFO] [stderr] 28 |   let an_integer = 5i32; // Suffix annotation
[INFO] [stderr]    |       ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_an_integer`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `default_float`
[INFO] [stderr]   --> src/chapters/c02.rs:31:7
[INFO] [stderr]    |
[INFO] [stderr] 31 |   let default_float = 3.0; // `f64`
[INFO] [stderr]    |       ^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_float`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `default_integer`
[INFO] [stderr]   --> src/chapters/c02.rs:32:7
[INFO] [stderr]    |
[INFO] [stderr] 32 |   let default_integer = 7; // `i32`
[INFO] [stderr]    |       ^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_default_integer`
[INFO] [stderr] 
[INFO] [stderr] warning: variable `inferred_type` is assigned to, but never used
[INFO] [stderr]   --> src/chapters/c02.rs:35:11
[INFO] [stderr]    |
[INFO] [stderr] 35 |   let mut inferred_type = 12; // Type i64 is inferred from another line
[INFO] [stderr]    |           ^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: consider using `_inferred_type` instead
[INFO] [stderr] 
[INFO] [stderr] warning: value assigned to `inferred_type` is never read
[INFO] [stderr]   --> src/chapters/c02.rs:36:3
[INFO] [stderr]    |
[INFO] [stderr] 36 |   inferred_type = 4294967296i64;
[INFO] [stderr]    |   ^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: variable `mutable` is assigned to, but never used
[INFO] [stderr]   --> src/chapters/c02.rs:39:11
[INFO] [stderr]    |
[INFO] [stderr] 39 |   let mut mutable = 12; // Mutable `i32`
[INFO] [stderr]    |           ^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: consider using `_mutable` instead
[INFO] [stderr] 
[INFO] [stderr] warning: value assigned to `mutable` is never read
[INFO] [stderr]   --> src/chapters/c02.rs:40:3
[INFO] [stderr]    |
[INFO] [stderr] 40 |   mutable = 21;
[INFO] [stderr]    |   ^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: maybe it is overwritten before being read?
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `mutable`
[INFO] [stderr]   --> src/chapters/c02.rs:46:7
[INFO] [stderr]    |
[INFO] [stderr] 46 |   let mutable = true;
[INFO] [stderr]    |       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_mutable`
[INFO] [stderr] 
[INFO] [stderr] warning: variant is never constructed: `Subtract`
[INFO] [stderr]    --> src/chapters/c03.rs:220:5
[INFO] [stderr]     |
[INFO] [stderr] 220 |     Subtract,
[INFO] [stderr]     |     ^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function `c_liKe_enums` should have a snake case name
[INFO] [stderr]    --> src/chapters/c03.rs:281:8
[INFO] [stderr]     |
[INFO] [stderr] 281 | pub fn c_liKe_enums() {
[INFO] [stderr]     |        ^^^^^^^^^^^^ help: convert the identifier to snake case: `c_li_ke_enums`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: `rust-by-example` (bin "rust-by-example" test) generated 12 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/rust_by_example-81241201ef66cc35)
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "16004f7bab51d665d0898505d3a5f0bc0693f48ebb9388e41af8976b1954d374", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "16004f7bab51d665d0898505d3a5f0bc0693f48ebb9388e41af8976b1954d374", kill_on_drop: false }`
[INFO] [stdout] 16004f7bab51d665d0898505d3a5f0bc0693f48ebb9388e41af8976b1954d374