[INFO] cloning repository https://github.com/puppypepper/rust_in_action
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/puppypepper/rust_in_action" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpuppypepper%2Frust_in_action", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpuppypepper%2Frust_in_action'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 86847e64cdba0a0800feca7401af0c9bffa92269
[INFO] checking puppypepper/rust_in_action/86847e64cdba0a0800feca7401af0c9bffa92269 against master#d8810e3e2dab96778d20dd6d746ff95465515509 for pr-137033
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpuppypepper%2Frust_in_action" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/puppypepper/rust_in_action on toolchain d8810e3e2dab96778d20dd6d746ff95465515509
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+d8810e3e2dab96778d20dd6d746ff95465515509" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/puppypepper/rust_in_action
[INFO] finished tweaking git repo https://github.com/puppypepper/rust_in_action
[INFO] tweaked toml for git repo https://github.com/puppypepper/rust_in_action written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/puppypepper/rust_in_action 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" "+d8810e3e2dab96778d20dd6d746ff95465515509" "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-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3959728d45483eb673ba100a951a6b9f5012970368db2a9e08e0ac9b67c8a5ad" "/opt/rustwide/cargo-home/bin/cargo" "+d8810e3e2dab96778d20dd6d746ff95465515509" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b017354886b7096f0149125571343f64203796600258a581889975592366f37f
[INFO] running `Command { std: "docker" "start" "-a" "b017354886b7096f0149125571343f64203796600258a581889975592366f37f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b017354886b7096f0149125571343f64203796600258a581889975592366f37f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b017354886b7096f0149125571343f64203796600258a581889975592366f37f", kill_on_drop: false }`
[INFO] [stdout] b017354886b7096f0149125571343f64203796600258a581889975592366f37f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3959728d45483eb673ba100a951a6b9f5012970368db2a9e08e0ac9b67c8a5ad" "/opt/rustwide/cargo-home/bin/cargo" "+d8810e3e2dab96778d20dd6d746ff95465515509" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 37a8b1c4e51407f509eaacb1f9886d51e3ec6e4e236a9b3c66cef917baf01d16
[INFO] running `Command { std: "docker" "start" "-a" "37a8b1c4e51407f509eaacb1f9886d51e3ec6e4e236a9b3c66cef917baf01d16", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.162
[INFO] [stderr]    Compiling proc-macro2 v1.0.92
[INFO] [stderr]     Checking byteorder v1.5.0
[INFO] [stderr]     Checking memchr v2.7.4
[INFO] [stderr]     Checking unicode-width v0.1.14
[INFO] [stderr]     Checking regex-syntax v0.8.5
[INFO] [stderr]     Checking strsim v0.8.0
[INFO] [stderr]     Checking vec_map v0.8.2
[INFO] [stderr]     Checking ansi_term v0.12.1
[INFO] [stderr]     Checking chapter-5 v0.1.0 (/opt/rustwide/workdir/chapter-5)
[INFO] [stderr]     Checking chapter-4 v0.1.0 (/opt/rustwide/workdir/chapter-4)
[INFO] [stderr]    Compiling num-traits v0.2.19
[INFO] [stdout] warning: unused variable: `exponent`
[INFO] [stdout]  --> chapter-5/src/list5-8.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let exponent = _exponent - 127;
[INFO] [stdout]   |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_exponent`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sat_id`
[INFO] [stdout]  --> chapter-4/src/list4-1.rs:6:18
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn check_message(sat_id: i64) -> StatusMessage {
[INFO] [stdout]   |                  ^^^^^^ help: if this is intentional, prefix it with an underscore: `_sat_id`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sat`
[INFO] [stdout]   --> chapter-4/src/list4-2.rs:10:18
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn check_message(sat: &CubeSat) -> StatusMessage {
[INFO] [stdout]    |                  ^^^ help: if this is intentional, prefix it with an underscore: `_sat`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> chapter-4/src/list4-2.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | struct CubeSat {
[INFO] [stdout]   |        ------- field in this struct
[INFO] [stdout] 2 |     id: i64,
[INFO] [stdout]   |     ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `current_opcode`, `run`, and `add_xy` are never used
[INFO] [stdout]   --> chapter-5/src/chip-8.rs:7:8
[INFO] [stdout]    |
[INFO] [stdout] 6  | impl CPU {
[INFO] [stdout]    | -------- methods in this implementation
[INFO] [stdout] 7  |     fn current_opcode(&self) -> u16 {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 11 |     fn run(&mut self) {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] ...
[INFO] [stdout] 27 |     fn add_xy(&mut self, x: u8, y: u8) {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sat`
[INFO] [stdout]   --> chapter-4/src/list4-18.rs:11:17
[INFO] [stdout]    |
[INFO] [stdout] 11 | fn check_status(sat: CubeSat) -> StatusMessage {
[INFO] [stdout]    |                 ^^^ help: if this is intentional, prefix it with an underscore: `_sat`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> chapter-4/src/list4-18.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct CubeSat {
[INFO] [stdout]   |        ------- field in this struct
[INFO] [stdout] 3 |     id: u64,
[INFO] [stdout]   |     ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `CubeSat` has a derived impl for the trait `Clone`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sat_id`
[INFO] [stdout]  --> chapter-4/src/list4-1.rs:6:18
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn check_message(sat_id: i64) -> StatusMessage {
[INFO] [stdout]   |                  ^^^^^^ help: if this is intentional, prefix it with an underscore: `_sat_id`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `exponent`
[INFO] [stdout]  --> chapter-5/src/list5-8.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let exponent = _exponent - 127;
[INFO] [stdout]   |         ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_exponent`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `current_opcode`, `run`, and `add_xy` are never used
[INFO] [stdout]   --> chapter-5/src/chip-8.rs:7:8
[INFO] [stdout]    |
[INFO] [stdout] 6  | impl CPU {
[INFO] [stdout]    | -------- methods in this implementation
[INFO] [stdout] 7  |     fn current_opcode(&self) -> u16 {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 11 |     fn run(&mut self) {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] ...
[INFO] [stdout] 27 |     fn add_xy(&mut self, x: u8, y: u8) {
[INFO] [stdout]    |        ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sat`
[INFO] [stdout]   --> chapter-4/src/list4-2.rs:10:18
[INFO] [stdout]    |
[INFO] [stdout] 10 | fn check_message(sat: &CubeSat) -> StatusMessage {
[INFO] [stdout]    |                  ^^^ help: if this is intentional, prefix it with an underscore: `_sat`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> chapter-4/src/list4-2.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | struct CubeSat {
[INFO] [stdout]   |        ------- field in this struct
[INFO] [stdout] 2 |     id: i64,
[INFO] [stdout]   |     ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `value` is never read
[INFO] [stdout]  --> chapter-4/src/list4-6.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct Demo {
[INFO] [stdout]   |        ---- field in this struct
[INFO] [stdout] 4 |     value: i32,
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `value` is never read
[INFO] [stdout]  --> chapter-4/src/list4-6.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | struct Demo {
[INFO] [stdout]   |        ---- field in this struct
[INFO] [stdout] 4 |     value: i32,
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sat`
[INFO] [stdout]   --> chapter-4/src/list4-18.rs:11:17
[INFO] [stdout]    |
[INFO] [stdout] 11 | fn check_status(sat: CubeSat) -> StatusMessage {
[INFO] [stdout]    |                 ^^^ help: if this is intentional, prefix it with an underscore: `_sat`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `id` is never read
[INFO] [stdout]  --> chapter-4/src/list4-18.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | struct CubeSat {
[INFO] [stdout]   |        ------- field in this struct
[INFO] [stdout] 3 |     id: u64,
[INFO] [stdout]   |     ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `CubeSat` has a derived impl for the trait `Clone`, but this is intentionally ignored during dead code analysis
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking aho-corasick v1.1.3
[INFO] [stderr]    Compiling quote v1.0.37
[INFO] [stderr]     Checking getrandom v0.2.15
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking clap v2.34.0
[INFO] [stderr]     Checking rand_core v0.6.4
[INFO] [stderr]     Checking num-integer v0.1.46
[INFO] [stderr]     Checking num-complex v0.4.6
[INFO] [stderr]    Compiling syn v2.0.89
[INFO] [stderr]     Checking num-bigint v0.4.6
[INFO] [stderr]     Checking num-iter v0.1.45
[INFO] [stderr]     Checking regex-automata v0.4.8
[INFO] [stderr]     Checking num-rational v0.4.2
[INFO] [stderr]     Checking num v0.4.3
[INFO] [stderr]     Checking rust_in_action v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling zerocopy-derive v0.7.35
[INFO] [stderr]     Checking zerocopy v0.7.35
[INFO] [stderr]     Checking ppv-lite86 v0.2.20
[INFO] [stderr]     Checking regex v1.11.1
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking grep-lite v0.1.0 (/opt/rustwide/workdir/grep-lite)
[INFO] [stderr]     Checking rand v0.8.5
[INFO] [stderr]     Checking chapter-3 v0.1.0 (/opt/rustwide/workdir/chapter-3)
[INFO] [stdout] warning: unused variable: `save_to`
[INFO] [stdout]  --> chapter-3/src/list3-12.rs:9:26
[INFO] [stdout]   |
[INFO] [stdout] 9 |     fn read(self: &File, save_to: &mut Vec<u8>) -> Result<usize, String> {
[INFO] [stdout]   |                          ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_save_to`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]  --> chapter-3/src/list3-1.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn open(f: &mut File) -> bool {
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]  --> chapter-3/src/list3-1.rs:9:10
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn close(f: &mut File) -> bool {
[INFO] [stdout]   |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-1.rs:13:9
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read(f: &mut File, save_to: &mut Vec<u8>) -> ! {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `save_to`
[INFO] [stdout]   --> chapter-3/src/list3-1.rs:13:23
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read(f: &mut File, save_to: &mut Vec<u8>) -> ! {
[INFO] [stdout]    |                       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_save_to`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `read` is never used
[INFO] [stdout]   --> chapter-3/src/list3-1.rs:13:4
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read(f: &mut File, save_to: &mut Vec<u8>) -> ! {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-5.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 | fn open(f: &mut File) -> bool {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let y = &x.data;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let z = &(x.data);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:48:9
[INFO] [stdout]    |
[INFO] [stdout] 48 |     let v = x.data;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let t = x.data2;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-5.rs:34:10
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn close(f: &mut File) -> bool {
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]  --> chapter-3/src/list3-3.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn open(f: &mut File) -> bool {
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-3.rs:11:10
[INFO] [stdout]    |
[INFO] [stdout] 11 | fn close(f: &mut File) -> bool {
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-5.rs:30:9
[INFO] [stdout]    |
[INFO] [stdout] 30 | fn open(f: &mut File) -> bool {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-5.rs:34:10
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn close(f: &mut File) -> bool {
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `save_to`
[INFO] [stdout]  --> chapter-3/src/list3-12.rs:9:26
[INFO] [stdout]   |
[INFO] [stdout] 9 |     fn read(self: &File, save_to: &mut Vec<u8>) -> Result<usize, String> {
[INFO] [stdout]   |                          ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_save_to`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]  --> chapter-3/src/list3-1.rs:5:9
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn open(f: &mut File) -> bool {
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]  --> chapter-3/src/list3-1.rs:9:10
[INFO] [stdout]   |
[INFO] [stdout] 9 | fn close(f: &mut File) -> bool {
[INFO] [stdout]   |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-1.rs:13:9
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read(f: &mut File, save_to: &mut Vec<u8>) -> ! {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `save_to`
[INFO] [stdout]   --> chapter-3/src/list3-1.rs:13:23
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read(f: &mut File, save_to: &mut Vec<u8>) -> ! {
[INFO] [stdout]    |                       ^^^^^^^ help: if this is intentional, prefix it with an underscore: `_save_to`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `read` is never used
[INFO] [stdout]   --> chapter-3/src/list3-1.rs:13:4
[INFO] [stdout]    |
[INFO] [stdout] 13 | fn read(f: &mut File, save_to: &mut Vec<u8>) -> ! {
[INFO] [stdout]    |    ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]  --> chapter-3/src/list3-3.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn open(f: &mut File) -> bool {
[INFO] [stdout]   |         ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]   --> chapter-3/src/list3-3.rs:11:10
[INFO] [stdout]    |
[INFO] [stdout] 11 | fn close(f: &mut File) -> bool {
[INFO] [stdout]    |          ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:45:9
[INFO] [stdout]    |
[INFO] [stdout] 45 |     let y = &x.data;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:46:9
[INFO] [stdout]    |
[INFO] [stdout] 46 |     let z = &(x.data);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:48:9
[INFO] [stdout]    |
[INFO] [stdout] 48 |     let v = x.data;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t`
[INFO] [stdout]   --> chapter-3/src/list3-2.rs:51:9
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let t = x.data2;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_t`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 14.57s
[INFO] running `Command { std: "docker" "inspect" "37a8b1c4e51407f509eaacb1f9886d51e3ec6e4e236a9b3c66cef917baf01d16", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "37a8b1c4e51407f509eaacb1f9886d51e3ec6e4e236a9b3c66cef917baf01d16", kill_on_drop: false }`
[INFO] [stdout] 37a8b1c4e51407f509eaacb1f9886d51e3ec6e4e236a9b3c66cef917baf01d16