[INFO] fetching crate unkai 0.2.0...
[INFO] testing unkai-0.2.0 against 1.90.0 for beta-1.91-3
[INFO] extracting crate unkai 0.2.0 into /workspace/builds/worker-0-tc1/source
[INFO] started tweaking crates.io crate unkai 0.2.0
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate unkai 0.2.0
[INFO] tweaked toml for crates.io crate unkai 0.2.0 written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate unkai 0.2.0 on toolchain 1.90.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate unkai 0.2.0 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" "+1.90.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded plotters-svg v0.3.6
[INFO] [stderr]   Downloaded plotters v0.3.6
[INFO] [stderr]   Downloaded syn v2.0.76
[INFO] [stderr]   Downloaded plotters-backend v0.3.6
[INFO] [stderr]   Downloaded serde_json v1.0.127
[INFO] [stderr]   Downloaded cc v1.1.15
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "+1.90.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 82d564ada40cc0cd55fc7c9dd7f7d04f45f7c97b4574b3823c6ec5bd6754180b
[INFO] running `Command { std: "docker" "start" "-a" "82d564ada40cc0cd55fc7c9dd7f7d04f45f7c97b4574b3823c6ec5bd6754180b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "82d564ada40cc0cd55fc7c9dd7f7d04f45f7c97b4574b3823c6ec5bd6754180b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "82d564ada40cc0cd55fc7c9dd7f7d04f45f7c97b4574b3823c6ec5bd6754180b", kill_on_drop: false }`
[INFO] [stdout] 82d564ada40cc0cd55fc7c9dd7f7d04f45f7c97b4574b3823c6ec5bd6754180b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "+1.90.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e7492282da3c13c885b425515e2c26bb4166f74acacf95b9178e186238b4e77a
[INFO] running `Command { std: "docker" "start" "-a" "e7492282da3c13c885b425515e2c26bb4166f74acacf95b9178e186238b4e77a", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.158
[INFO] [stderr]    Compiling memchr v2.7.4
[INFO] [stderr]    Compiling smallvec v1.13.2
[INFO] [stderr]    Compiling gimli v0.29.0
[INFO] [stderr]    Compiling rustc-demangle v0.1.24
[INFO] [stderr]    Compiling hashbrown v0.14.5
[INFO] [stderr]    Compiling cc v1.1.15
[INFO] [stderr]    Compiling miniz_oxide v0.7.4
[INFO] [stderr]    Compiling object v0.36.4
[INFO] [stderr]    Compiling parking_lot_core v0.9.10
[INFO] [stderr]    Compiling backtrace v0.3.73
[INFO] [stderr]    Compiling dashmap v5.5.3
[INFO] [stderr]    Compiling addr2line v0.22.0
[INFO] [stderr]    Compiling unkai v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:51:1
[INFO] [stdout]    |
[INFO] [stdout] 51 | #![feature(allocator_api)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `unkai` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "e7492282da3c13c885b425515e2c26bb4166f74acacf95b9178e186238b4e77a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e7492282da3c13c885b425515e2c26bb4166f74acacf95b9178e186238b4e77a", kill_on_drop: false }`
[INFO] [stdout] e7492282da3c13c885b425515e2c26bb4166f74acacf95b9178e186238b4e77a