[INFO] cloning repository https://github.com/gs0510/Dibba
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/gs0510/Dibba" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgs0510%2FDibba", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgs0510%2FDibba'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] e5189be5d50d00c8d3bae907ec4150a0eade3595
[INFO] testing gs0510/Dibba against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgs0510%2FDibba" "/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/gs0510/Dibba on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/gs0510/Dibba
[INFO] finished tweaking git repo https://github.com/gs0510/Dibba
[INFO] tweaked toml for git repo https://github.com/gs0510/Dibba written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/gs0510/Dibba already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "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] 6be717fea935d6ed1a4012bd2526a15839b5eb846c9eab648a33fa9cf15ee5a2
[INFO] running `Command { std: "docker" "start" "-a" "6be717fea935d6ed1a4012bd2526a15839b5eb846c9eab648a33fa9cf15ee5a2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6be717fea935d6ed1a4012bd2526a15839b5eb846c9eab648a33fa9cf15ee5a2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6be717fea935d6ed1a4012bd2526a15839b5eb846c9eab648a33fa9cf15ee5a2", kill_on_drop: false }`
[INFO] [stdout] 6be717fea935d6ed1a4012bd2526a15839b5eb846c9eab648a33fa9cf15ee5a2
[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=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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "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] ca6ebdac792a5b93f2f709c282d583106995dc7c8c5b29088a1d3a435d240837
[INFO] running `Command { std: "docker" "start" "-a" "ca6ebdac792a5b93f2f709c282d583106995dc7c8c5b29088a1d3a435d240837", kill_on_drop: false }`
[INFO] [stderr]    Compiling nix v0.13.0
[INFO] [stderr]    Compiling container v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `thread`, `time`
[INFO] [stdout]  --> src/main.rs:8:11
[INFO] [stdout]   |
[INFO] [stdout] 8 | use std::{thread, time};
[INFO] [stdout]   |           ^^^^^^  ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:10:45
[INFO] [stdout]    |
[INFO] [stdout] 10 | type Result<T> = std::result::Result<T, Box<std::error::Error>>;
[INFO] [stdout]    |                                             ^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 10 - type Result<T> = std::result::Result<T, Box<std::error::Error>>;
[INFO] [stdout] 10 + type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `string`
[INFO] [stdout]   --> src/main.rs:57:10
[INFO] [stdout]    |
[INFO] [stdout] 57 | fn child(string: &str) -> Result<()> {
[INFO] [stdout]    |          ^^^^^^ help: if this is intentional, prefix it with an underscore: `_string`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `setup_root_dir`
[INFO] [stdout]    --> src/main.rs:111:4
[INFO] [stdout]     |
[INFO] [stdout] 111 | fn setup_root_dir(root_path: &Path) -> Result<()> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `cleanup_root_dir`
[INFO] [stdout]    --> src/main.rs:124:4
[INFO] [stdout]     |
[INFO] [stdout] 124 | fn cleanup_root_dir(root_dir: &Path) -> Result<()> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     setns(-1, CloneFlags::CLONE_NEWUTS);
[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 `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:22:5
[INFO] [stdout]    |
[INFO] [stdout] 22 |     setns(-1, CloneFlags::CLONE_NEWPID);
[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: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:53:5
[INFO] [stdout]    |
[INFO] [stdout] 53 |     fs::write(pid_max, "20".as_bytes());
[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: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 9.46s
[INFO] running `Command { std: "docker" "inspect" "ca6ebdac792a5b93f2f709c282d583106995dc7c8c5b29088a1d3a435d240837", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ca6ebdac792a5b93f2f709c282d583106995dc7c8c5b29088a1d3a435d240837", kill_on_drop: false }`
[INFO] [stdout] ca6ebdac792a5b93f2f709c282d583106995dc7c8c5b29088a1d3a435d240837
[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=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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen" "--no-run" "--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] 8e7a2ab5c5047f7122728fd73b6a2813a90cf1c826a4667df22da49b17d1edda
[INFO] running `Command { std: "docker" "start" "-a" "8e7a2ab5c5047f7122728fd73b6a2813a90cf1c826a4667df22da49b17d1edda", kill_on_drop: false }`
[INFO] [stderr]    Compiling container v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `thread`, `time`
[INFO] [stdout]  --> src/main.rs:8:11
[INFO] [stdout]   |
[INFO] [stdout] 8 | use std::{thread, time};
[INFO] [stdout]   |           ^^^^^^  ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:10:45
[INFO] [stdout]    |
[INFO] [stdout] 10 | type Result<T> = std::result::Result<T, Box<std::error::Error>>;
[INFO] [stdout]    |                                             ^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 10 - type Result<T> = std::result::Result<T, Box<std::error::Error>>;
[INFO] [stdout] 10 + type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `string`
[INFO] [stdout]   --> src/main.rs:57:10
[INFO] [stdout]    |
[INFO] [stdout] 57 | fn child(string: &str) -> Result<()> {
[INFO] [stdout]    |          ^^^^^^ help: if this is intentional, prefix it with an underscore: `_string`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `setup_root_dir`
[INFO] [stdout]    --> src/main.rs:111:4
[INFO] [stdout]     |
[INFO] [stdout] 111 | fn setup_root_dir(root_path: &Path) -> Result<()> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `cleanup_root_dir`
[INFO] [stdout]    --> src/main.rs:124:4
[INFO] [stdout]     |
[INFO] [stdout] 124 | fn cleanup_root_dir(root_dir: &Path) -> Result<()> {
[INFO] [stdout]     |    ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     setns(-1, CloneFlags::CLONE_NEWUTS);
[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 `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:22:5
[INFO] [stdout]    |
[INFO] [stdout] 22 |     setns(-1, CloneFlags::CLONE_NEWPID);
[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: unused `std::result::Result` that must be used
[INFO] [stdout]   --> src/main.rs:53:5
[INFO] [stdout]    |
[INFO] [stdout] 53 |     fs::write(pid_max, "20".as_bytes());
[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: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.17s
[INFO] running `Command { std: "docker" "inspect" "8e7a2ab5c5047f7122728fd73b6a2813a90cf1c826a4667df22da49b17d1edda", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8e7a2ab5c5047f7122728fd73b6a2813a90cf1c826a4667df22da49b17d1edda", kill_on_drop: false }`
[INFO] [stdout] 8e7a2ab5c5047f7122728fd73b6a2813a90cf1c826a4667df22da49b17d1edda
[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=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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 715f7b3767c47a7ce911c85f66f6d871c4d9077d7ac3854b191b13d609254769
[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" "715f7b3767c47a7ce911c85f66f6d871c4d9077d7ac3854b191b13d609254769", kill_on_drop: false }`
[INFO] [stderr] warning: unused imports: `thread`, `time`
[INFO] [stderr]  --> src/main.rs:8:11
[INFO] [stderr]   |
[INFO] [stderr] 8 | use std::{thread, time};
[INFO] [stderr]   |           ^^^^^^  ^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/main.rs:10:45
[INFO] [stderr]    |
[INFO] [stderr] 10 | type Result<T> = std::result::Result<T, Box<std::error::Error>>;
[INFO] [stderr]    |                                             ^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 10 - type Result<T> = std::result::Result<T, Box<std::error::Error>>;
[INFO] [stderr] 10 + type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
[INFO] [stderr]    | 
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `string`
[INFO] [stderr]   --> src/main.rs:57:10
[INFO] [stderr]    |
[INFO] [stderr] 57 | fn child(string: &str) -> Result<()> {
[INFO] [stderr]    |          ^^^^^^ help: if this is intentional, prefix it with an underscore: `_string`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `setup_root_dir`
[INFO] [stderr]    --> src/main.rs:111:4
[INFO] [stderr]     |
[INFO] [stderr] 111 | fn setup_root_dir(root_path: &Path) -> Result<()> {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: function is never used: `cleanup_root_dir`
[INFO] [stderr]    --> src/main.rs:124:4
[INFO] [stderr]     |
[INFO] [stderr] 124 | fn cleanup_root_dir(root_dir: &Path) -> Result<()> {
[INFO] [stderr]     |    ^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:21:5
[INFO] [stderr]    |
[INFO] [stderr] 21 |     setns(-1, CloneFlags::CLONE_NEWUTS);
[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 `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:22:5
[INFO] [stderr]    |
[INFO] [stderr] 22 |     setns(-1, CloneFlags::CLONE_NEWPID);
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]   --> src/main.rs:53:5
[INFO] [stderr]    |
[INFO] [stderr] 53 |     fs::write(pid_max, "20".as_bytes());
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: `container` (bin "container" test) generated 8 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/container-ebe36bf16b2a7679)
[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" "715f7b3767c47a7ce911c85f66f6d871c4d9077d7ac3854b191b13d609254769", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "715f7b3767c47a7ce911c85f66f6d871c4d9077d7ac3854b191b13d609254769", kill_on_drop: false }`
[INFO] [stdout] 715f7b3767c47a7ce911c85f66f6d871c4d9077d7ac3854b191b13d609254769