[INFO] cloning repository https://github.com/tayorh27/intermediate-concepts
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tayorh27/intermediate-concepts" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftayorh27%2Fintermediate-concepts", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftayorh27%2Fintermediate-concepts'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 32bc0ccecc2fb26f0dac34cda76d60ee235462e2
[INFO] testing tayorh27/intermediate-concepts against master#ebf0cf75d368c035f4c7e7246d203bd469ee4a51 for pr-137940-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftayorh27%2Fintermediate-concepts" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/tayorh27/intermediate-concepts on toolchain ebf0cf75d368c035f4c7e7246d203bd469ee4a51
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ebf0cf75d368c035f4c7e7246d203bd469ee4a51" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/tayorh27/intermediate-concepts
[INFO] finished tweaking git repo https://github.com/tayorh27/intermediate-concepts
[INFO] tweaked toml for git repo https://github.com/tayorh27/intermediate-concepts written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/tayorh27/intermediate-concepts 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" "+ebf0cf75d368c035f4c7e7246d203bd469ee4a51" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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@sha256:1680c8fbd8dfb46fcd6d22e546df16ab0e007457dc29fcd9e987cdd5077fd1af" "/opt/rustwide/cargo-home/bin/cargo" "+ebf0cf75d368c035f4c7e7246d203bd469ee4a51" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] eb9ab5e301676dab016c775cfbe24eda3f2c4dae9b1a2aa4cda00c81b394f52e
[INFO] running `Command { std: "docker" "start" "-a" "eb9ab5e301676dab016c775cfbe24eda3f2c4dae9b1a2aa4cda00c81b394f52e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "eb9ab5e301676dab016c775cfbe24eda3f2c4dae9b1a2aa4cda00c81b394f52e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "eb9ab5e301676dab016c775cfbe24eda3f2c4dae9b1a2aa4cda00c81b394f52e", kill_on_drop: false }`
[INFO] [stdout] eb9ab5e301676dab016c775cfbe24eda3f2c4dae9b1a2aa4cda00c81b394f52e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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@sha256:1680c8fbd8dfb46fcd6d22e546df16ab0e007457dc29fcd9e987cdd5077fd1af" "/opt/rustwide/cargo-home/bin/cargo" "+ebf0cf75d368c035f4c7e7246d203bd469ee4a51" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 327e7deb20120d3f1dc8fff8e5d1ea470d32748dd150119d687133e56b0df5e7
[INFO] running `Command { std: "docker" "start" "-a" "327e7deb20120d3f1dc8fff8e5d1ea470d32748dd150119d687133e56b0df5e7", kill_on_drop: false }`
[INFO] [stderr]    Compiling intermediate-concepts v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `ErrorKind`
[INFO] [stdout]  --> src/main.rs:4:22
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::io::{Error, ErrorKind}; 
[INFO] [stdout]   |                      ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `rec1`
[INFO] [stdout]   --> src/main.rs:80:9
[INFO] [stdout]    |
[INFO] [stdout] 80 |     let rec1 = Rectangle{height: 1, width: 2};
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_rec1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `rec1`
[INFO] [stdout]   --> src/main.rs:81:9
[INFO] [stdout]    |
[INFO] [stdout] 81 |     let rec1 = Rectangle{height: 1.65, width: 2.22};
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_rec1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cube1`
[INFO] [stdout]   --> src/main.rs:83:9
[INFO] [stdout]    |
[INFO] [stdout] 83 |     let cube1 = Cube{height: 1, width: 2, length: 3};
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_cube1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cube1`
[INFO] [stdout]   --> src/main.rs:84:9
[INFO] [stdout]    |
[INFO] [stdout] 84 |     let cube1 = Cube{height: 1.54, width: 2, length: 3.75};
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_cube1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `object`
[INFO] [stdout]   --> src/main.rs:93:23
[INFO] [stdout]    |
[INFO] [stdout] 93 | fn lookup_datatype<T>(object: T) {
[INFO] [stdout]    |                       ^^^^^^ help: if this is intentional, prefix it with an underscore: `_object`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:206:9
[INFO] [stdout]     |
[INFO] [stdout] 206 |     let x = closures_example_1(1, 3);
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `os_command` is never used
[INFO] [stdout]  --> src/main.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn os_command() {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `error_handling_example` is never used
[INFO] [stdout]   --> src/main.rs:24:4
[INFO] [stdout]    |
[INFO] [stdout] 24 | fn error_handling_example(dir: &str) -> Result<i32, Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Option` is never used
[INFO] [stdout]   --> src/main.rs:52:7
[INFO] [stdout]    |
[INFO] [stdout] 52 | enum  Option<T> {
[INFO] [stdout]    |       ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `MResult` is never used
[INFO] [stdout]   --> src/main.rs:57:7
[INFO] [stdout]    |
[INFO] [stdout] 57 | enum  MResult<T, E> {
[INFO] [stdout]    |       ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Custom` is never used
[INFO] [stdout]   --> src/main.rs:62:6
[INFO] [stdout]    |
[INFO] [stdout] 62 | enum Custom<T,U> {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Rectangle` is never constructed
[INFO] [stdout]   --> src/main.rs:68:9
[INFO] [stdout]    |
[INFO] [stdout] 68 | struct  Rectangle<T> {
[INFO] [stdout]    |         ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Cube` is never constructed
[INFO] [stdout]   --> src/main.rs:73:9
[INFO] [stdout]    |
[INFO] [stdout] 73 | struct  Cube<T,U,V> {
[INFO] [stdout]    |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `struct_example` is never used
[INFO] [stdout]   --> src/main.rs:79:4
[INFO] [stdout]    |
[INFO] [stdout] 79 | fn struct_example() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `closure_example_2` is never used
[INFO] [stdout]    --> src/main.rs:169:4
[INFO] [stdout]     |
[INFO] [stdout] 169 | fn closure_example_2() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.38s
[INFO] running `Command { std: "docker" "inspect" "327e7deb20120d3f1dc8fff8e5d1ea470d32748dd150119d687133e56b0df5e7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "327e7deb20120d3f1dc8fff8e5d1ea470d32748dd150119d687133e56b0df5e7", kill_on_drop: false }`
[INFO] [stdout] 327e7deb20120d3f1dc8fff8e5d1ea470d32748dd150119d687133e56b0df5e7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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@sha256:1680c8fbd8dfb46fcd6d22e546df16ab0e007457dc29fcd9e987cdd5077fd1af" "/opt/rustwide/cargo-home/bin/cargo" "+ebf0cf75d368c035f4c7e7246d203bd469ee4a51" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] de42628f8e63a14c02dbc67de4f4ec58a20576ce51619f8c138252c757d3b451
[INFO] running `Command { std: "docker" "start" "-a" "de42628f8e63a14c02dbc67de4f4ec58a20576ce51619f8c138252c757d3b451", kill_on_drop: false }`
[INFO] [stderr]    Compiling intermediate-concepts v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `ErrorKind`
[INFO] [stdout]  --> src/main.rs:4:22
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::io::{Error, ErrorKind}; 
[INFO] [stdout]   |                      ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `rec1`
[INFO] [stdout]   --> src/main.rs:80:9
[INFO] [stdout]    |
[INFO] [stdout] 80 |     let rec1 = Rectangle{height: 1, width: 2};
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_rec1`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `rec1`
[INFO] [stdout]   --> src/main.rs:81:9
[INFO] [stdout]    |
[INFO] [stdout] 81 |     let rec1 = Rectangle{height: 1.65, width: 2.22};
[INFO] [stdout]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_rec1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cube1`
[INFO] [stdout]   --> src/main.rs:83:9
[INFO] [stdout]    |
[INFO] [stdout] 83 |     let cube1 = Cube{height: 1, width: 2, length: 3};
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_cube1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `cube1`
[INFO] [stdout]   --> src/main.rs:84:9
[INFO] [stdout]    |
[INFO] [stdout] 84 |     let cube1 = Cube{height: 1.54, width: 2, length: 3.75};
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_cube1`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `object`
[INFO] [stdout]   --> src/main.rs:93:23
[INFO] [stdout]    |
[INFO] [stdout] 93 | fn lookup_datatype<T>(object: T) {
[INFO] [stdout]    |                       ^^^^^^ help: if this is intentional, prefix it with an underscore: `_object`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]    --> src/main.rs:206:9
[INFO] [stdout]     |
[INFO] [stdout] 206 |     let x = closures_example_1(1, 3);
[INFO] [stdout]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `os_command` is never used
[INFO] [stdout]  --> src/main.rs:6:4
[INFO] [stdout]   |
[INFO] [stdout] 6 | fn os_command() {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `error_handling_example` is never used
[INFO] [stdout]   --> src/main.rs:24:4
[INFO] [stdout]    |
[INFO] [stdout] 24 | fn error_handling_example(dir: &str) -> Result<i32, Error> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Option` is never used
[INFO] [stdout]   --> src/main.rs:52:7
[INFO] [stdout]    |
[INFO] [stdout] 52 | enum  Option<T> {
[INFO] [stdout]    |       ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `MResult` is never used
[INFO] [stdout]   --> src/main.rs:57:7
[INFO] [stdout]    |
[INFO] [stdout] 57 | enum  MResult<T, E> {
[INFO] [stdout]    |       ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Custom` is never used
[INFO] [stdout]   --> src/main.rs:62:6
[INFO] [stdout]    |
[INFO] [stdout] 62 | enum Custom<T,U> {
[INFO] [stdout]    |      ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Rectangle` is never constructed
[INFO] [stdout]   --> src/main.rs:68:9
[INFO] [stdout]    |
[INFO] [stdout] 68 | struct  Rectangle<T> {
[INFO] [stdout]    |         ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Cube` is never constructed
[INFO] [stdout]   --> src/main.rs:73:9
[INFO] [stdout]    |
[INFO] [stdout] 73 | struct  Cube<T,U,V> {
[INFO] [stdout]    |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `struct_example` is never used
[INFO] [stdout]   --> src/main.rs:79:4
[INFO] [stdout]    |
[INFO] [stdout] 79 | fn struct_example() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `closure_example_2` is never used
[INFO] [stdout]    --> src/main.rs:169:4
[INFO] [stdout]     |
[INFO] [stdout] 169 | fn closure_example_2() {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.23s
[INFO] running `Command { std: "docker" "inspect" "de42628f8e63a14c02dbc67de4f4ec58a20576ce51619f8c138252c757d3b451", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "de42628f8e63a14c02dbc67de4f4ec58a20576ce51619f8c138252c757d3b451", kill_on_drop: false }`
[INFO] [stdout] de42628f8e63a14c02dbc67de4f4ec58a20576ce51619f8c138252c757d3b451
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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@sha256:1680c8fbd8dfb46fcd6d22e546df16ab0e007457dc29fcd9e987cdd5077fd1af" "/opt/rustwide/cargo-home/bin/cargo" "+ebf0cf75d368c035f4c7e7246d203bd469ee4a51" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 864391dfeb005b24589812e33b24f6d5913bb112ffbea4da538179753b95faee
[INFO] running `Command { std: "docker" "start" "-a" "864391dfeb005b24589812e33b24f6d5913bb112ffbea4da538179753b95faee", kill_on_drop: false }`
[INFO] [stderr] warning: unused import: `ErrorKind`
[INFO] [stderr]  --> src/main.rs:4:22
[INFO] [stderr]   |
[INFO] [stderr] 4 | use std::io::{Error, ErrorKind}; 
[INFO] [stderr]   |                      ^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `rec1`
[INFO] [stderr]   --> src/main.rs:80:9
[INFO] [stderr]    |
[INFO] [stderr] 80 |     let rec1 = Rectangle{height: 1, width: 2};
[INFO] [stderr]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_rec1`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `rec1`
[INFO] [stderr]   --> src/main.rs:81:9
[INFO] [stderr]    |
[INFO] [stderr] 81 |     let rec1 = Rectangle{height: 1.65, width: 2.22};
[INFO] [stderr]    |         ^^^^ help: if this is intentional, prefix it with an underscore: `_rec1`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `cube1`
[INFO] [stderr]   --> src/main.rs:83:9
[INFO] [stderr]    |
[INFO] [stderr] 83 |     let cube1 = Cube{height: 1, width: 2, length: 3};
[INFO] [stderr]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_cube1`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `cube1`
[INFO] [stderr]   --> src/main.rs:84:9
[INFO] [stderr]    |
[INFO] [stderr] 84 |     let cube1 = Cube{height: 1.54, width: 2, length: 3.75};
[INFO] [stderr]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_cube1`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `object`
[INFO] [stderr]   --> src/main.rs:93:23
[INFO] [stderr]    |
[INFO] [stderr] 93 | fn lookup_datatype<T>(object: T) {
[INFO] [stderr]    |                       ^^^^^^ help: if this is intentional, prefix it with an underscore: `_object`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `x`
[INFO] [stderr]    --> src/main.rs:206:9
[INFO] [stderr]     |
[INFO] [stderr] 206 |     let x = closures_example_1(1, 3);
[INFO] [stderr]     |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stderr] 
[INFO] [stderr] warning: function `os_command` is never used
[INFO] [stderr]  --> src/main.rs:6:4
[INFO] [stderr]   |
[INFO] [stderr] 6 | fn os_command() {
[INFO] [stderr]   |    ^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function `error_handling_example` is never used
[INFO] [stderr]   --> src/main.rs:24:4
[INFO] [stderr]    |
[INFO] [stderr] 24 | fn error_handling_example(dir: &str) -> Result<i32, Error> {
[INFO] [stderr]    |    ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum `Option` is never used
[INFO] [stderr]   --> src/main.rs:52:7
[INFO] [stderr]    |
[INFO] [stderr] 52 | enum  Option<T> {
[INFO] [stderr]    |       ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum `MResult` is never used
[INFO] [stderr]   --> src/main.rs:57:7
[INFO] [stderr]    |
[INFO] [stderr] 57 | enum  MResult<T, E> {
[INFO] [stderr]    |       ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: enum `Custom` is never used
[INFO] [stderr]   --> src/main.rs:62:6
[INFO] [stderr]    |
[INFO] [stderr] 62 | enum Custom<T,U> {
[INFO] [stderr]    |      ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct `Rectangle` is never constructed
[INFO] [stderr]   --> src/main.rs:68:9
[INFO] [stderr]    |
[INFO] [stderr] 68 | struct  Rectangle<T> {
[INFO] [stderr]    |         ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: struct `Cube` is never constructed
[INFO] [stderr]   --> src/main.rs:73:9
[INFO] [stderr]    |
[INFO] [stderr] 73 | struct  Cube<T,U,V> {
[INFO] [stderr]    |         ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function `struct_example` is never used
[INFO] [stderr]   --> src/main.rs:79:4
[INFO] [stderr]    |
[INFO] [stderr] 79 | fn struct_example() {
[INFO] [stderr]    |    ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function `closure_example_2` is never used
[INFO] [stderr]    --> src/main.rs:169:4
[INFO] [stderr]     |
[INFO] [stderr] 169 | fn closure_example_2() {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: `intermediate-concepts` (bin "intermediate-concepts" test) generated 16 warnings (run `cargo fix --bin "intermediate-concepts" --tests` to apply 1 suggestion)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests src/main.rs (/opt/rustwide/target/debug/deps/intermediate_concepts-21c7a5fbcfc639c0)
[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" "864391dfeb005b24589812e33b24f6d5913bb112ffbea4da538179753b95faee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "864391dfeb005b24589812e33b24f6d5913bb112ffbea4da538179753b95faee", kill_on_drop: false }`
[INFO] [stdout] 864391dfeb005b24589812e33b24f6d5913bb112ffbea4da538179753b95faee