[INFO] fetching crate phlow 2.0.1...
[INFO] testing phlow-2.0.1 against beta-2025-09-21 for beta-1.91-3
[INFO] extracting crate phlow 2.0.1 into /workspace/builds/worker-5-tc2/source
[INFO] started tweaking crates.io crate phlow 2.0.1
[INFO] finished tweaking crates.io crate phlow 2.0.1
[INFO] tweaked toml for crates.io crate phlow 2.0.1 written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate phlow 2.0.1 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 63 packages to latest compatible versions
[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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 4f07895adeb52ac89d9f16b5dfa940374427dc7206952d842896e63d5dce8c14
[INFO] running `Command { std: "docker" "start" "-a" "4f07895adeb52ac89d9f16b5dfa940374427dc7206952d842896e63d5dce8c14", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4f07895adeb52ac89d9f16b5dfa940374427dc7206952d842896e63d5dce8c14", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4f07895adeb52ac89d9f16b5dfa940374427dc7206952d842896e63d5dce8c14", kill_on_drop: false }`
[INFO] [stdout] 4f07895adeb52ac89d9f16b5dfa940374427dc7206952d842896e63d5dce8c14
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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] 749796fa43e9b354f2db2da673be12ebd54bcd04c8a98e33d3f0f4d919a3ae66
[INFO] running `Command { std: "docker" "start" "-a" "749796fa43e9b354f2db2da673be12ebd54bcd04c8a98e33d3f0f4d919a3ae66", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.101
[INFO] [stderr]    Compiling unicode-ident v1.0.19
[INFO] [stderr]    Compiling quote v1.0.41
[INFO] [stderr]    Compiling autocfg v1.5.0
[INFO] [stderr]    Compiling parking_lot_core v0.9.11
[INFO] [stderr]    Compiling futures-task v0.3.31
[INFO] [stderr]    Compiling slab v0.4.11
[INFO] [stderr]    Compiling scopeguard v1.2.0
[INFO] [stderr]    Compiling futures-core v0.3.31
[INFO] [stderr]    Compiling pin-project-lite v0.2.16
[INFO] [stderr]    Compiling smallvec v1.15.1
[INFO] [stderr]    Compiling pin-utils v0.1.0
[INFO] [stderr]    Compiling log v0.4.28
[INFO] [stderr]    Compiling lock_api v0.4.13
[INFO] [stderr]    Compiling rust-format v0.3.4
[INFO] [stderr]    Compiling parking_lot v0.12.4
[INFO] [stderr]    Compiling syn v2.0.106
[INFO] [stderr]    Compiling futures-macro v0.3.31
[INFO] [stderr]    Compiling phlow-derive v2.0.0
[INFO] [stderr]    Compiling futures-util v0.3.31
[INFO] [stderr]    Compiling futures-executor v0.3.31
[INFO] [stderr]    Compiling phlow v2.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:4:35
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![cfg_attr(feature = "printing", feature(specialization))]
[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 `phlow` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "749796fa43e9b354f2db2da673be12ebd54bcd04c8a98e33d3f0f4d919a3ae66", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "749796fa43e9b354f2db2da673be12ebd54bcd04c8a98e33d3f0f4d919a3ae66", kill_on_drop: false }`
[INFO] [stdout] 749796fa43e9b354f2db2da673be12ebd54bcd04c8a98e33d3f0f4d919a3ae66