[INFO] cloning repository https://github.com/wismer/advent-2020
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/wismer/advent-2020" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwismer%2Fadvent-2020", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwismer%2Fadvent-2020'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 9592c366609efaf34fb8f8effa4d76a3f2fa846f
[INFO] testing wismer/advent-2020 against try#722e1797249a965b6335aebd65d777f917e498f1 for pr-91031
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwismer%2Fadvent-2020" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/wismer/advent-2020 on toolchain 722e1797249a965b6335aebd65d777f917e498f1
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/wismer/advent-2020
[INFO] finished tweaking git repo https://github.com/wismer/advent-2020
[INFO] tweaked toml for git repo https://github.com/wismer/advent-2020 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/wismer/advent-2020 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 9a6cc85e75860126b9669736d21c8fd3738d5ace4b9e612a14961e6962c16502
[INFO] running `Command { std: "docker" "start" "-a" "9a6cc85e75860126b9669736d21c8fd3738d5ace4b9e612a14961e6962c16502", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9a6cc85e75860126b9669736d21c8fd3738d5ace4b9e612a14961e6962c16502", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9a6cc85e75860126b9669736d21c8fd3738d5ace4b9e612a14961e6962c16502", kill_on_drop: false }`
[INFO] [stdout] 9a6cc85e75860126b9669736d21c8fd3738d5ace4b9e612a14961e6962c16502
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] b2f17a9aa4790ab7dfbb2e5e6d93896936ceea5ebb07170bb354bcabb1275070
[INFO] running `Command { std: "docker" "start" "-a" "b2f17a9aa4790ab7dfbb2e5e6d93896936ceea5ebb07170bb354bcabb1275070", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: value assigned to `id` is never read
[INFO] [stdout]   --> src/main.rs:96:13
[INFO] [stdout]    |
[INFO] [stdout] 96 |     let mut id = 0;
[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: unused variable: `new_group`
[INFO] [stdout]    --> src/main.rs:127:13
[INFO] [stdout]     |
[INFO] [stdout] 127 |     let mut new_group = false;
[INFO] [stdout]     |             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_group`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `number_of_answers`
[INFO] [stdout]    --> src/main.rs:157:9
[INFO] [stdout]     |
[INFO] [stdout] 157 |     let number_of_answers = answers.len();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_number_of_answers`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:127:9
[INFO] [stdout]     |
[INFO] [stdout] 127 |     let mut new_group = false;
[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: function is never used: `parse_input_part_one`
[INFO] [stdout]   --> src/main.rs:17:4
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn parse_input_part_one(numbers: &Vec<usize>) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `parse_input_part_two`
[INFO] [stdout]   --> src/main.rs:40:4
[INFO] [stdout]    |
[INFO] [stdout] 40 | fn parse_input_part_two(numbers: &Vec<usize>) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `parse_day_five`
[INFO] [stdout]   --> src/main.rs:68:4
[INFO] [stdout]    |
[INFO] [stdout] 68 | fn parse_day_five() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `parse_seating`
[INFO] [stdout]   --> src/main.rs:91:4
[INFO] [stdout]    |
[INFO] [stdout] 91 | fn parse_seating(seating: Vec<char>) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:71:5
[INFO] [stdout]    |
[INFO] [stdout] 71 |     file.read_to_string(&mut buffer);
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:124:5
[INFO] [stdout]     |
[INFO] [stdout] 124 |     data.read_to_string(&mut buffer);
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.41s
[INFO] running `Command { std: "docker" "inspect" "b2f17a9aa4790ab7dfbb2e5e6d93896936ceea5ebb07170bb354bcabb1275070", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b2f17a9aa4790ab7dfbb2e5e6d93896936ceea5ebb07170bb354bcabb1275070", kill_on_drop: false }`
[INFO] [stdout] b2f17a9aa4790ab7dfbb2e5e6d93896936ceea5ebb07170bb354bcabb1275070
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d7d2d7e6a6fdba155926c719ddc5b42f0c9699dc1ddf4ecf59003e5e85aee55a
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "d7d2d7e6a6fdba155926c719ddc5b42f0c9699dc1ddf4ecf59003e5e85aee55a", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: value assigned to `id` is never read
[INFO] [stdout]   --> src/main.rs:96:13
[INFO] [stdout]    |
[INFO] [stdout] 96 |     let mut id = 0;
[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: unused variable: `new_group`
[INFO] [stdout]    --> src/main.rs:127:13
[INFO] [stdout]     |
[INFO] [stdout] 127 |     let mut new_group = false;
[INFO] [stdout]     |             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_group`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `number_of_answers`
[INFO] [stdout]    --> src/main.rs:157:9
[INFO] [stdout]     |
[INFO] [stdout] 157 |     let number_of_answers = answers.len();
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_number_of_answers`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/main.rs:127:9
[INFO] [stdout]     |
[INFO] [stdout] 127 |     let mut new_group = false;
[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: function is never used: `parse_input_part_one`
[INFO] [stdout]   --> src/main.rs:17:4
[INFO] [stdout]    |
[INFO] [stdout] 17 | fn parse_input_part_one(numbers: &Vec<usize>) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `parse_input_part_two`
[INFO] [stdout]   --> src/main.rs:40:4
[INFO] [stdout]    |
[INFO] [stdout] 40 | fn parse_input_part_two(numbers: &Vec<usize>) {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `parse_day_five`
[INFO] [stdout]   --> src/main.rs:68:4
[INFO] [stdout]    |
[INFO] [stdout] 68 | fn parse_day_five() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `parse_seating`
[INFO] [stdout]   --> src/main.rs:91:4
[INFO] [stdout]    |
[INFO] [stdout] 91 | fn parse_seating(seating: Vec<char>) -> usize {
[INFO] [stdout]    |    ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:71:5
[INFO] [stdout]    |
[INFO] [stdout] 71 |     file.read_to_string(&mut buffer);
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/main.rs:124:5
[INFO] [stdout]     |
[INFO] [stdout] 124 |     data.read_to_string(&mut buffer);
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.73s
[INFO] running `Command { std: "docker" "inspect" "d7d2d7e6a6fdba155926c719ddc5b42f0c9699dc1ddf4ecf59003e5e85aee55a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d7d2d7e6a6fdba155926c719ddc5b42f0c9699dc1ddf4ecf59003e5e85aee55a", kill_on_drop: false }`
[INFO] [stdout] d7d2d7e6a6fdba155926c719ddc5b42f0c9699dc1ddf4ecf59003e5e85aee55a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+722e1797249a965b6335aebd65d777f917e498f1" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 59b1bc5153d30f4228ebe1fc9a4f5ace5c4fcaf61e21b473b065a7ef9e4a5088
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "59b1bc5153d30f4228ebe1fc9a4f5ace5c4fcaf61e21b473b065a7ef9e4a5088", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: value assigned to `id` is never read
[INFO] [stdout] running 0 tests
[INFO] [stderr]   --> src/main.rs:96:13
[INFO] [stdout] 
[INFO] [stderr]    |
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] 96 |     let mut id = 0;
[INFO] [stdout] 
[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: unused variable: `new_group`
[INFO] [stderr]    --> src/main.rs:127:13
[INFO] [stderr]     |
[INFO] [stderr] 127 |     let mut new_group = false;
[INFO] [stderr]     |             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_new_group`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `number_of_answers`
[INFO] [stderr]    --> src/main.rs:157:9
[INFO] [stderr]     |
[INFO] [stderr] 157 |     let number_of_answers = answers.len();
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_number_of_answers`
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:127:9
[INFO] [stderr]     |
[INFO] [stderr] 127 |     let mut new_group = false;
[INFO] [stderr]     |         ----^^^^^^^^^
[INFO] [stderr]     |         |
[INFO] [stderr]     |         help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `parse_input_part_one`
[INFO] [stderr]   --> src/main.rs:17:4
[INFO] [stderr]    |
[INFO] [stderr] 17 | fn parse_input_part_one(numbers: &Vec<usize>) {
[INFO] [stderr]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `parse_input_part_two`
[INFO] [stderr]   --> src/main.rs:40:4
[INFO] [stderr]    |
[INFO] [stderr] 40 | fn parse_input_part_two(numbers: &Vec<usize>) {
[INFO] [stderr]    |    ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `parse_day_five`
[INFO] [stderr]   --> src/main.rs:68:4
[INFO] [stderr]    |
[INFO] [stderr] 68 | fn parse_day_five() {
[INFO] [stderr]    |    ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `parse_seating`
[INFO] [stderr]   --> src/main.rs:91:4
[INFO] [stderr]    |
[INFO] [stderr] 91 | fn parse_seating(seating: Vec<char>) -> usize {
[INFO] [stderr]    |    ^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]   --> src/main.rs:71:5
[INFO] [stderr]    |
[INFO] [stderr] 71 |     file.read_to_string(&mut buffer);
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Result` that must be used
[INFO] [stderr]    --> src/main.rs:124:5
[INFO] [stderr]     |
[INFO] [stderr] 124 |     data.read_to_string(&mut buffer);
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: `rust` (bin "rust" test) generated 10 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.01s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/rust-4961faa5eb6faed1)
[INFO] running `Command { std: "docker" "inspect" "59b1bc5153d30f4228ebe1fc9a4f5ace5c4fcaf61e21b473b065a7ef9e4a5088", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "59b1bc5153d30f4228ebe1fc9a4f5ace5c4fcaf61e21b473b065a7ef9e4a5088", kill_on_drop: false }`
[INFO] [stdout] 59b1bc5153d30f4228ebe1fc9a4f5ace5c4fcaf61e21b473b065a7ef9e4a5088