[INFO] fetching crate phlow-ffi 2.0.0...
[INFO] testing phlow-ffi-2.0.0 against 1.90.0 for beta-1.91-3
[INFO] extracting crate phlow-ffi 2.0.0 into /workspace/builds/worker-6-tc1/source
[INFO] started tweaking crates.io crate phlow-ffi 2.0.0
[INFO] finished tweaking crates.io crate phlow-ffi 2.0.0
[INFO] tweaked toml for crates.io crate phlow-ffi 2.0.0 written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate phlow-ffi 2.0.0 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] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]      Locking 43 packages to latest compatible versions
[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 user-error v1.2.8
[INFO] [stderr]   Downloaded string-box v1.1.1
[INFO] [stderr]   Downloaded rust-format v0.3.4
[INFO] [stderr]   Downloaded phlow v2.0.1
[INFO] [stderr]   Downloaded phlow-derive v2.0.0
[INFO] [stderr]   Downloaded value-box v2.3.3
[INFO] [stderr]   Downloaded phlow-derive v1.4.0
[INFO] [stderr]   Downloaded phlow v1.7.1
[INFO] [stderr]   Downloaded widestring v1.2.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] cb38e79916e9cbb420d0adc17c7f1a20284f06d37704e7efe46147bee1e470b8
[INFO] running `Command { std: "docker" "start" "-a" "cb38e79916e9cbb420d0adc17c7f1a20284f06d37704e7efe46147bee1e470b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cb38e79916e9cbb420d0adc17c7f1a20284f06d37704e7efe46147bee1e470b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cb38e79916e9cbb420d0adc17c7f1a20284f06d37704e7efe46147bee1e470b8", kill_on_drop: false }`
[INFO] [stdout] cb38e79916e9cbb420d0adc17c7f1a20284f06d37704e7efe46147bee1e470b8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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] fed17058165fe49fb0b39d8d6124025a5cd3c781f8bb7ff3a9f7fb71f8da10f9
[INFO] running `Command { std: "docker" "start" "-a" "fed17058165fe49fb0b39d8d6124025a5cd3c781f8bb7ff3a9f7fb71f8da10f9", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v2.0.106
[INFO] [stderr]    Compiling autocfg v1.5.0
[INFO] [stderr]    Compiling parking_lot_core v0.9.11
[INFO] [stderr]    Compiling rust-format v0.3.4
[INFO] [stderr]    Compiling scopeguard v1.2.0
[INFO] [stderr]    Compiling smallvec v1.15.1
[INFO] [stderr]    Compiling thiserror v1.0.69
[INFO] [stderr]    Compiling futures-core v0.3.31
[INFO] [stderr]    Compiling futures-task v0.3.31
[INFO] [stderr]    Compiling user-error v1.2.8
[INFO] [stderr]    Compiling widestring v1.2.0
[INFO] [stderr]    Compiling lock_api v0.4.13
[INFO] [stderr]    Compiling parking_lot v0.12.4
[INFO] [stderr]    Compiling string-box v1.1.1
[INFO] [stderr]    Compiling futures-macro v0.3.31
[INFO] [stderr]    Compiling phlow-derive v1.4.0
[INFO] [stderr]    Compiling thiserror-impl v1.0.69
[INFO] [stderr]    Compiling phlow-derive v2.0.0
[INFO] [stderr]    Compiling phlow v1.7.1
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/phlow-1.7.1/src/lib.rs:4:35
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![cfg_attr(feature = "printing", feature(specialization))]
[INFO] [stdout]   |                                   ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling futures-util v0.3.31
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `phlow` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "fed17058165fe49fb0b39d8d6124025a5cd3c781f8bb7ff3a9f7fb71f8da10f9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "fed17058165fe49fb0b39d8d6124025a5cd3c781f8bb7ff3a9f7fb71f8da10f9", kill_on_drop: false }`
[INFO] [stdout] fed17058165fe49fb0b39d8d6124025a5cd3c781f8bb7ff3a9f7fb71f8da10f9