[INFO] cloning repository https://github.com/spcan/easy-complex
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/spcan/easy-complex" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fspcan%2Feasy-complex", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fspcan%2Feasy-complex'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] b37cb1f226fe8364da7666cbf15c00f03cceb179
[INFO] testing spcan/easy-complex against try#0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6 for pr-137122-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fspcan%2Feasy-complex" "/workspace/builds/worker-3-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/spcan/easy-complex
[INFO] finished tweaking git repo https://github.com/spcan/easy-complex
[INFO] tweaked toml for git repo https://github.com/spcan/easy-complex written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/spcan/easy-complex on toolchain 0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/spcan/easy-complex 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" "+0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2024
[INFO] [stderr] warning: `panic` setting is ignored for `bench` profile
[INFO] [stderr] warning: `panic` setting is ignored for `test` profile
[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-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b8089cdb9211de819c7ab506c974caa9aad6ecb2d842444f2a74981d95cae3b9
[INFO] running `Command { std: "docker" "start" "-a" "b8089cdb9211de819c7ab506c974caa9aad6ecb2d842444f2a74981d95cae3b9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b8089cdb9211de819c7ab506c974caa9aad6ecb2d842444f2a74981d95cae3b9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b8089cdb9211de819c7ab506c974caa9aad6ecb2d842444f2a74981d95cae3b9", kill_on_drop: false }`
[INFO] [stdout] b8089cdb9211de819c7ab506c974caa9aad6ecb2d842444f2a74981d95cae3b9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d665d0d1aae7bf74d0189abdcb1729144532925a9f5dec4ee277a72e45b591e4
[INFO] running `Command { std: "docker" "start" "-a" "d665d0d1aae7bf74d0189abdcb1729144532925a9f5dec4ee277a72e45b591e4", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2024
[INFO] [stderr] warning: `panic` setting is ignored for `bench` profile
[INFO] [stderr] warning: `panic` setting is ignored for `test` profile
[INFO] [stderr]    Compiling easy_complex v0.4.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]  --> src/lib.rs:7:8
[INFO] [stdout]   |
[INFO] [stdout] 7 |     #[cfg(std)]
[INFO] [stdout]   |           ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: expected names are: `docsrs`, `feature`, and `test` and 31 more
[INFO] [stdout]   = help: consider using a Cargo feature instead
[INFO] [stdout]   = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]            [lints.rust]
[INFO] [stdout]            unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]   = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout]   = note: `#[warn(unexpected_cfgs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]   --> src/lib.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout] 10 |     #[cfg(not(std))]
[INFO] [stdout]    |               ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider using a Cargo feature instead
[INFO] [stdout]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]             [lints.rust]
[INFO] [stdout]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]   --> src/lib.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 13 |     #[cfg(not(std))]
[INFO] [stdout]    |               ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider using a Cargo feature instead
[INFO] [stdout]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]             [lints.rust]
[INFO] [stdout]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [optimized + debuginfo] target(s) in 0.58s
[INFO] running `Command { std: "docker" "inspect" "d665d0d1aae7bf74d0189abdcb1729144532925a9f5dec4ee277a72e45b591e4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d665d0d1aae7bf74d0189abdcb1729144532925a9f5dec4ee277a72e45b591e4", kill_on_drop: false }`
[INFO] [stdout] d665d0d1aae7bf74d0189abdcb1729144532925a9f5dec4ee277a72e45b591e4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9fa3f5b4105c43e813573e54da10d4007c715e9348b28e4f0610d1a8571eb0c6
[INFO] running `Command { std: "docker" "start" "-a" "9fa3f5b4105c43e813573e54da10d4007c715e9348b28e4f0610d1a8571eb0c6", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2024
[INFO] [stderr] warning: `panic` setting is ignored for `bench` profile
[INFO] [stderr] warning: `panic` setting is ignored for `test` profile
[INFO] [stderr]    Compiling easy_complex v0.4.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]  --> src/lib.rs:7:8
[INFO] [stdout]   |
[INFO] [stdout] 7 |     #[cfg(std)]
[INFO] [stdout]   |           ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: expected names are: `docsrs`, `feature`, and `test` and 31 more
[INFO] [stdout]   = help: consider using a Cargo feature instead
[INFO] [stdout]   = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]            [lints.rust]
[INFO] [stdout]            unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]   = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout]   = note: `#[warn(unexpected_cfgs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]   --> src/lib.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout] 10 |     #[cfg(not(std))]
[INFO] [stdout]    |               ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider using a Cargo feature instead
[INFO] [stdout]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]             [lints.rust]
[INFO] [stdout]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]   --> src/lib.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 13 |     #[cfg(not(std))]
[INFO] [stdout]    |               ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider using a Cargo feature instead
[INFO] [stdout]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]             [lints.rust]
[INFO] [stdout]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]  --> src/lib.rs:7:8
[INFO] [stdout]   |
[INFO] [stdout] 7 |     #[cfg(std)]
[INFO] [stdout]   |           ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: expected names are: `docsrs`, `feature`, and `test` and 31 more
[INFO] [stdout]   = help: consider using a Cargo feature instead
[INFO] [stdout]   = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]            [lints.rust]
[INFO] [stdout]            unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]   = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout]   = note: `#[warn(unexpected_cfgs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]   --> src/lib.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout] 10 |     #[cfg(not(std))]
[INFO] [stdout]    |               ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider using a Cargo feature instead
[INFO] [stdout]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]             [lints.rust]
[INFO] [stdout]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `std`
[INFO] [stdout]   --> src/lib.rs:13:12
[INFO] [stdout]    |
[INFO] [stdout] 13 |     #[cfg(not(std))]
[INFO] [stdout]    |               ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = help: consider using a Cargo feature instead
[INFO] [stdout]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stdout]             [lints.rust]
[INFO] [stdout]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stdout]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stdout]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.55s
[INFO] running `Command { std: "docker" "inspect" "9fa3f5b4105c43e813573e54da10d4007c715e9348b28e4f0610d1a8571eb0c6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9fa3f5b4105c43e813573e54da10d4007c715e9348b28e4f0610d1a8571eb0c6", kill_on_drop: false }`
[INFO] [stdout] 9fa3f5b4105c43e813573e54da10d4007c715e9348b28e4f0610d1a8571eb0c6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/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@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+0936b3db0ae648ba2d5b60eb08cf4faf2ddab0c6" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 5b6e7aebecb52c86083f8960bac0543b52f09b39820c9a91fee5a3f660c21785
[INFO] running `Command { std: "docker" "start" "-a" "5b6e7aebecb52c86083f8960bac0543b52f09b39820c9a91fee5a3f660c21785", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2024
[INFO] [stderr] warning: `panic` setting is ignored for `bench` profile
[INFO] [stderr] warning: `panic` setting is ignored for `test` profile
[INFO] [stderr] warning: unexpected `cfg` condition name: `std`
[INFO] [stderr]  --> src/lib.rs:7:8
[INFO] [stderr]   |
[INFO] [stderr] 7 |     #[cfg(std)]
[INFO] [stderr]   |           ^^^
[INFO] [stderr]   |
[INFO] [stderr]   = help: expected names are: `docsrs`, `feature`, and `test` and 31 more
[INFO] [stderr]   = help: consider using a Cargo feature instead
[INFO] [stderr]   = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stderr]            [lints.rust]
[INFO] [stderr]            unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stderr]   = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stderr]   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stderr]   = note: `#[warn(unexpected_cfgs)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unexpected `cfg` condition name: `std`
[INFO] [stderr]   --> src/lib.rs:10:12
[INFO] [stderr]    |
[INFO] [stderr] 10 |     #[cfg(not(std))]
[INFO] [stderr]    |               ^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: consider using a Cargo feature instead
[INFO] [stderr]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stderr]             [lints.rust]
[INFO] [stderr]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stderr]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stderr]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stderr] 
[INFO] [stderr] warning: unexpected `cfg` condition name: `std`
[INFO] [stderr]   --> src/lib.rs:13:12
[INFO] [stderr]    |
[INFO] [stderr] 13 |     #[cfg(not(std))]
[INFO] [stderr]    |               ^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: consider using a Cargo feature instead
[INFO] [stderr]    = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
[INFO] [stderr]             [lints.rust]
[INFO] [stderr]             unexpected_cfgs = { level = "warn", check-cfg = ['cfg(std)'] }
[INFO] [stderr]    = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(std)");` to the top of the `build.rs`
[INFO] [stderr]    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
[INFO] [stderr] 
[INFO] [stderr] warning: `easy_complex` (lib) generated 3 warnings
[INFO] [stderr] warning: `easy_complex` (lib test) generated 3 warnings (3 duplicates)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.04s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/easy_complex-47aa0a1c921cc714)
[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] [stderr]    Doc-tests easy_complex
[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" "5b6e7aebecb52c86083f8960bac0543b52f09b39820c9a91fee5a3f660c21785", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b6e7aebecb52c86083f8960bac0543b52f09b39820c9a91fee5a3f660c21785", kill_on_drop: false }`
[INFO] [stdout] 5b6e7aebecb52c86083f8960bac0543b52f09b39820c9a91fee5a3f660c21785