[INFO] fetching crate forkable 0.1.0...
[INFO] testing forkable-0.1.0 against beta-2026-04-21 for beta-1.96-2
[INFO] extracting crate forkable 0.1.0 into /workspace/builds/worker-4-tc2/source
[INFO] started tweaking crates.io crate forkable 0.1.0
[INFO] finished tweaking crates.io crate forkable 0.1.0
[INFO] tweaked toml for crates.io crate forkable 0.1.0 written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate forkable 0.1.0 on toolchain beta-2026-04-21
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "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-2026-04-21" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 15 packages to latest compatible versions
[INFO] [stderr]       Adding circularing v2.2.1 (available: v3.0.0)
[INFO] [stderr]       Adding snafu v0.8.9 (available: v0.9.0)
[INFO] [stderr]       Adding spin v0.9.8 (available: v0.10.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8887ba6f3ae69e74c203f3fa0a14c50947d60ebcf555c3ff1fff7fa9e4470414
[INFO] running `Command { std: "docker" "start" "-a" "8887ba6f3ae69e74c203f3fa0a14c50947d60ebcf555c3ff1fff7fa9e4470414", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8887ba6f3ae69e74c203f3fa0a14c50947d60ebcf555c3ff1fff7fa9e4470414", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8887ba6f3ae69e74c203f3fa0a14c50947d60ebcf555c3ff1fff7fa9e4470414", kill_on_drop: false }`
[INFO] [stdout] 8887ba6f3ae69e74c203f3fa0a14c50947d60ebcf555c3ff1fff7fa9e4470414
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4f7c43bf4dd3d809731b17ff59c9e67e3a18c9487eb18ec1ad63703a7c737e6c
[INFO] running `Command { std: "docker" "start" "-a" "4f7c43bf4dd3d809731b17ff59c9e67e3a18c9487eb18ec1ad63703a7c737e6c", kill_on_drop: false }`
[INFO] [stderr]    Compiling quote v1.0.45
[INFO] [stderr]    Compiling unicode-ident v1.0.24
[INFO] [stderr]    Compiling semver v1.0.28
[INFO] [stderr]    Compiling paste v1.0.15
[INFO] [stderr]    Compiling likeness v1.1.0
[INFO] [stderr]    Compiling spin v0.9.8
[INFO] [stderr]    Compiling circularing v2.2.1
[INFO] [stderr]    Compiling proc-macro2 v1.0.106
[INFO] [stderr]    Compiling rustc_version v0.4.1
[INFO] [stderr]    Compiling syn v2.0.117
[INFO] [stderr]    Compiling forkable v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling snafu-derive v0.8.9
[INFO] [stderr]    Compiling snafu v0.8.9
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:2:34
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(feature = "nightly", feature(error_in_core))]
[INFO] [stdout]   |                                  ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition value: `nightly`
[INFO] [stdout]  --> src/lib.rs:2:13
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(feature = "nightly", feature(error_in_core))]
[INFO] [stdout]   |             ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: expected values for `feature` are: `default` and `std`
[INFO] [stdout]   = help: consider adding `nightly` 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]   = note: `#[warn(unexpected_cfgs)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unexpected `cfg` condition value: `nightly`
[INFO] [stdout]  --> src/lib.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 | #[cfg(feature = "nightly")]
[INFO] [stdout]   |       ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: expected values for `feature` are: `default` and `std`
[INFO] [stdout]   = help: consider adding `nightly` 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: `nightly`
[INFO] [stdout]  --> src/lib.rs:6:32
[INFO] [stdout]   |
[INFO] [stdout] 6 | #[cfg(all(feature = "std", not(feature = "nightly")))]
[INFO] [stdout]   |                                ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: expected values for `feature` are: `default` and `std`
[INFO] [stdout]   = help: consider adding `nightly` 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: `nightly`
[INFO] [stdout]  --> src/lib.rs:9:38
[INFO] [stdout]   |
[INFO] [stdout] 9 | #[cfg(all(not(feature = "std"),  not(feature = "nightly")))]
[INFO] [stdout]   |                                      ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: expected values for `feature` are: `default` and `std`
[INFO] [stdout]   = help: consider adding `nightly` 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: the feature `error_in_core` has been stable since 1.81.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> src/lib.rs:2:42
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![cfg_attr(feature = "nightly", feature(error_in_core))]
[INFO] [stdout]   |                                          ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `forkable` (lib) due to 1 previous error; 5 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "4f7c43bf4dd3d809731b17ff59c9e67e3a18c9487eb18ec1ad63703a7c737e6c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4f7c43bf4dd3d809731b17ff59c9e67e3a18c9487eb18ec1ad63703a7c737e6c", kill_on_drop: false }`
[INFO] [stdout] 4f7c43bf4dd3d809731b17ff59c9e67e3a18c9487eb18ec1ad63703a7c737e6c
