[INFO] fetching crate structural 0.4.3...
[INFO] testing structural-0.4.3 against beta-2025-09-21 for beta-1.91-3
[INFO] extracting crate structural 0.4.3 into /workspace/builds/worker-3-tc2/source
[INFO] started tweaking crates.io crate structural 0.4.3
[INFO] finished tweaking crates.io crate structural 0.4.3
[INFO] tweaked toml for crates.io crate structural 0.4.3 written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate structural 0.4.3 on toolchain beta-2025-09-21
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-09-21" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-09-21" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 11 packages to latest compatible versions
[INFO] [stderr]       Adding core_extensions v0.1.20 (available: v1.5.4)
[INFO] [stderr]       Adding rustc_version v0.2.3 (available: v0.4.1)
[INFO] [stderr]       Adding typed-arena v1.5.0 (available: v1.7.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-09-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: `default_features` is deprecated in favor of `default-features` and will not work in the 2024 edition
[INFO] [stderr] (in the `core_extensions` dependency)
[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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-09-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0c29dcb17e5753a13fb098f92a12e82f888932c1d0d184fbeec44a13aac54852
[INFO] running `Command { std: "docker" "start" "-a" "0c29dcb17e5753a13fb098f92a12e82f888932c1d0d184fbeec44a13aac54852", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0c29dcb17e5753a13fb098f92a12e82f888932c1d0d184fbeec44a13aac54852", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0c29dcb17e5753a13fb098f92a12e82f888932c1d0d184fbeec44a13aac54852", kill_on_drop: false }`
[INFO] [stdout] 0c29dcb17e5753a13fb098f92a12e82f888932c1d0d184fbeec44a13aac54852
[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=warn" "-e" "RUSTDOCFLAGS=--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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-09-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 850368cdde54f975fb8f09797c4802211927072327075c65ab1da49d29aa2a12
[INFO] running `Command { std: "docker" "start" "-a" "850368cdde54f975fb8f09797c4802211927072327075c65ab1da49d29aa2a12", kill_on_drop: false }`
[INFO] [stderr] warning: `default_features` is deprecated in favor of `default-features` and will not work in the 2024 edition
[INFO] [stderr] (in the `core_extensions` dependency)
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling typed-arena v1.5.0
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling core_extensions v0.1.20
[INFO] [stderr]    Compiling as_derive_utils v0.8.3
[INFO] [stderr]    Compiling structural_derive v0.4.3
[INFO] [stderr]    Compiling structural v0.4.3 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unexpected `cfg` condition name: `rust_1_41`
[INFO] [stdout]    --> src/lib.rs:778:41
[INFO] [stdout]     |
[INFO] [stdout] 778 | #[cfg(any(feature = "for_examples", all(rust_1_41, doc)))]
[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(rust_1_41)'] }
[INFO] [stdout]     = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(rust_1_41)");` 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: `rust_1_41`
[INFO] [stdout]    --> src/lib.rs:784:50
[INFO] [stdout]     |
[INFO] [stdout] 784 | #[cfg(all(not(feature = "for_examples"), not(all(rust_1_41, doc))))]
[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(rust_1_41)'] }
[INFO] [stdout]     = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(rust_1_41)");` 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 value: `rust_1_42`
[INFO] [stdout]    --> src/utils.rs:135:11
[INFO] [stdout]     |
[INFO] [stdout] 135 |     #[cfg(feature = "rust_1_42")]
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: expected values for `feature` are: `all`, `alloc`, `default`, `disable_const_str`, `for_examples`, `hide_reexports`, `impl_fields`, `nightly_impl_fields`, `nightly_specialization`, `nightly_use_const_str`, `specialization`, `std`, `test_all`, `testing`, and `use_const_str`
[INFO] [stdout]     = help: consider adding `rust_1_42` as a feature in `Cargo.toml`
[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 value: `rust_1_42`
[INFO] [stdout]    --> src/utils.rs:139:15
[INFO] [stdout]     |
[INFO] [stdout] 139 |     #[cfg(not(feature = "rust_1_42"))]
[INFO] [stdout]     |               ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: expected values for `feature` are: `all`, `alloc`, `default`, `disable_const_str`, `for_examples`, `hide_reexports`, `impl_fields`, `nightly_impl_fields`, `nightly_specialization`, `nightly_use_const_str`, `specialization`, `std`, `test_all`, `testing`, and `use_const_str`
[INFO] [stdout]     = help: consider adding `rust_1_42` as a feature in `Cargo.toml`
[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: function cannot return without recursing
[INFO] [stdout]   --> src/utils.rs:37:5
[INFO] [stdout]    |
[INFO] [stdout] 37 |     fn drop(&mut self) {
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^ cannot return without recursing
[INFO] [stdout] ...
[INFO] [stdout] 40 |     }
[INFO] [stdout]    |     - recursive call site
[INFO] [stdout]    |
[INFO] [stdout]    = help: a `loop` may express intention better if this is on purpose
[INFO] [stdout]    = note: `#[warn(unconditional_recursion)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `InfinitePanic` is never constructed
[INFO] [stdout]   --> src/utils.rs:34:19
[INFO] [stdout]    |
[INFO] [stdout] 34 | pub(crate) struct InfinitePanic;
[INFO] [stdout]    |                   ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 7.60s
[INFO] running `Command { std: "docker" "inspect" "850368cdde54f975fb8f09797c4802211927072327075c65ab1da49d29aa2a12", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "850368cdde54f975fb8f09797c4802211927072327075c65ab1da49d29aa2a12", kill_on_drop: false }`
[INFO] [stdout] 850368cdde54f975fb8f09797c4802211927072327075c65ab1da49d29aa2a12
[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=warn" "-e" "RUSTDOCFLAGS=--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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-09-21" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 56375ab75b4d7dce742e30025f5f89cccd3d3b02354cba91b82bfd7411d4f431
[INFO] running `Command { std: "docker" "start" "-a" "56375ab75b4d7dce742e30025f5f89cccd3d3b02354cba91b82bfd7411d4f431", kill_on_drop: false }`
[INFO] [stderr] warning: `default_features` is deprecated in favor of `default-features` and will not work in the 2024 edition
[INFO] [stderr] (in the `core_extensions` dependency)
[INFO] [stdout] warning: unexpected `cfg` condition name: `rust_1_41`
[INFO] [stdout]    --> src/lib.rs:778:41
[INFO] [stdout]     |
[INFO] [stdout] 778 | #[cfg(any(feature = "for_examples", all(rust_1_41, doc)))]
[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(rust_1_41)'] }
[INFO] [stdout]     = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(rust_1_41)");` 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: `rust_1_41`
[INFO] [stdout]    --> src/lib.rs:784:50
[INFO] [stdout]     |
[INFO] [stdout] 784 | #[cfg(all(not(feature = "for_examples"), not(all(rust_1_41, doc))))]
[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(rust_1_41)'] }
[INFO] [stdout]     = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(rust_1_41)");` 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 value: `rust_1_42`
[INFO] [stdout]    --> src/utils.rs:135:11
[INFO] [stdout]     |
[INFO] [stdout] 135 |     #[cfg(feature = "rust_1_42")]
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: expected values for `feature` are: `all`, `alloc`, `default`, `disable_const_str`, `for_examples`, `hide_reexports`, `impl_fields`, `nightly_impl_fields`, `nightly_specialization`, `nightly_use_const_str`, `specialization`, `std`, `test_all`, `testing`, and `use_const_str`
[INFO] [stdout]     = help: consider adding `rust_1_42` as a feature in `Cargo.toml`
[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 value: `rust_1_42`
[INFO] [stdout]    --> src/utils.rs:139:15
[INFO] [stdout]     |
[INFO] [stdout] 139 |     #[cfg(not(feature = "rust_1_42"))]
[INFO] [stdout]     |               ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: expected values for `feature` are: `all`, `alloc`, `default`, `disable_const_str`, `for_examples`, `hide_reexports`, `impl_fields`, `nightly_impl_fields`, `nightly_specialization`, `nightly_use_const_str`, `specialization`, `std`, `test_all`, `testing`, and `use_const_str`
[INFO] [stdout]     = help: consider adding `rust_1_42` as a feature in `Cargo.toml`
[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]    Compiling structural v0.4.3 (/opt/rustwide/workdir)
[INFO] [stdout] warning: function cannot return without recursing
[INFO] [stdout]   --> src/utils.rs:37:5
[INFO] [stdout]    |
[INFO] [stdout] 37 |     fn drop(&mut self) {
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^ cannot return without recursing
[INFO] [stdout] ...
[INFO] [stdout] 40 |     }
[INFO] [stdout]    |     - recursive call site
[INFO] [stdout]    |
[INFO] [stdout]    = help: a `loop` may express intention better if this is on purpose
[INFO] [stdout]    = note: `#[warn(unconditional_recursion)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `InfinitePanic` is never constructed
[INFO] [stdout]   --> src/utils.rs:34:19
[INFO] [stdout]    |
[INFO] [stdout] 34 | pub(crate) struct InfinitePanic;
[INFO] [stdout]    |                   ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: tests must be run with the "testing" feature
[INFO] [stdout]    --> src/lib.rs:788:1
[INFO] [stdout]     |
[INFO] [stdout] 788 | compile_error! { "tests must be run with the \"testing\" feature" }
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `crate::test_utils`
[INFO] [stdout]    --> src/field/array_impls.rs:323:24
[INFO] [stdout]     |
[INFO] [stdout] 323 |             use crate::test_utils::DecOnDrop;
[INFO] [stdout]     |                        ^^^^^^^^^^ could not find `test_utils` in the crate root
[INFO] [stdout]     |
[INFO] [stdout] note: found an item that was configured out
[INFO] [stdout]    --> src/lib.rs:705:9
[INFO] [stdout]     |
[INFO] [stdout] 704 | #[cfg(feature = "testing")]
[INFO] [stdout]     |       ------------------- the item is gated behind the `testing` feature
[INFO] [stdout] 705 | pub mod test_utils;
[INFO] [stdout]     |         ^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition name: `rust_1_41`
[INFO] [stdout]    --> src/lib.rs:778:41
[INFO] [stdout]     |
[INFO] [stdout] 778 | #[cfg(any(feature = "for_examples", all(rust_1_41, doc)))]
[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(rust_1_41)'] }
[INFO] [stdout]     = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(rust_1_41)");` 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: `rust_1_41`
[INFO] [stdout]    --> src/lib.rs:784:50
[INFO] [stdout]     |
[INFO] [stdout] 784 | #[cfg(all(not(feature = "for_examples"), not(all(rust_1_41, doc))))]
[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(rust_1_41)'] }
[INFO] [stdout]     = help: or consider adding `println!("cargo::rustc-check-cfg=cfg(rust_1_41)");` 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 value: `rust_1_42`
[INFO] [stdout]    --> src/utils.rs:135:11
[INFO] [stdout]     |
[INFO] [stdout] 135 |     #[cfg(feature = "rust_1_42")]
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: expected values for `feature` are: `all`, `alloc`, `default`, `disable_const_str`, `for_examples`, `hide_reexports`, `impl_fields`, `nightly_impl_fields`, `nightly_specialization`, `nightly_use_const_str`, `specialization`, `std`, `test_all`, `testing`, and `use_const_str`
[INFO] [stdout]     = help: consider adding `rust_1_42` as a feature in `Cargo.toml`
[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 value: `rust_1_42`
[INFO] [stdout]    --> src/utils.rs:139:15
[INFO] [stdout]     |
[INFO] [stdout] 139 |     #[cfg(not(feature = "rust_1_42"))]
[INFO] [stdout]     |               ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: expected values for `feature` are: `all`, `alloc`, `default`, `disable_const_str`, `for_examples`, `hide_reexports`, `impl_fields`, `nightly_impl_fields`, `nightly_specialization`, `nightly_use_const_str`, `specialization`, `std`, `test_all`, `testing`, and `use_const_str`
[INFO] [stdout]     = help: consider adding `rust_1_42` as a feature in `Cargo.toml`
[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: function cannot return without recursing
[INFO] [stdout]   --> src/utils.rs:37:5
[INFO] [stdout]    |
[INFO] [stdout] 37 |     fn drop(&mut self) {
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^ cannot return without recursing
[INFO] [stdout] ...
[INFO] [stdout] 40 |     }
[INFO] [stdout]    |     - recursive call site
[INFO] [stdout]    |
[INFO] [stdout]    = help: a `loop` may express intention better if this is on purpose
[INFO] [stdout]    = note: `#[warn(unconditional_recursion)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0432`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `structural` (lib test) due to 2 previous errors; 5 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "56375ab75b4d7dce742e30025f5f89cccd3d3b02354cba91b82bfd7411d4f431", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "56375ab75b4d7dce742e30025f5f89cccd3d3b02354cba91b82bfd7411d4f431", kill_on_drop: false }`
[INFO] [stdout] 56375ab75b4d7dce742e30025f5f89cccd3d3b02354cba91b82bfd7411d4f431
