[INFO] fetching crate singleton-attr-proc-macro 0.1.9...
[INFO] testing singleton-attr-proc-macro-0.1.9 against beta-2025-10-28 for beta-1.92-2
[INFO] extracting crate singleton-attr-proc-macro 0.1.9 into /workspace/builds/worker-1-tc2/source
[INFO] started tweaking crates.io crate singleton-attr-proc-macro 0.1.9
[INFO] finished tweaking crates.io crate singleton-attr-proc-macro 0.1.9
[INFO] tweaked toml for crates.io crate singleton-attr-proc-macro 0.1.9 written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate singleton-attr-proc-macro 0.1.9 on toolchain beta-2025-10-28
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-10-28" "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-2025-10-28" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]      Locking 4 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-2025-10-28" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-10-28" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b78933c9e3211a058e17274b3f9f5582abf4297c9a52d0e46feb6703ae43e6b8
[INFO] running `Command { std: "docker" "start" "-a" "b78933c9e3211a058e17274b3f9f5582abf4297c9a52d0e46feb6703ae43e6b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b78933c9e3211a058e17274b3f9f5582abf4297c9a52d0e46feb6703ae43e6b8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b78933c9e3211a058e17274b3f9f5582abf4297c9a52d0e46feb6703ae43e6b8", kill_on_drop: false }`
[INFO] [stdout] b78933c9e3211a058e17274b3f9f5582abf4297c9a52d0e46feb6703ae43e6b8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-10-28" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] cec16e0a70ba07aa9603c475e3b59041f2d104723d438bd4d6f4e891dc2fee07
[INFO] running `Command { std: "docker" "start" "-a" "cec16e0a70ba07aa9603c475e3b59041f2d104723d438bd4d6f4e891dc2fee07", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.103
[INFO] [stderr]    Compiling quote v1.0.41
[INFO] [stderr]    Compiling unicode-ident v1.0.22
[INFO] [stderr]    Compiling syn v2.0.108
[INFO] [stderr]    Compiling singleton-attr-proc-macro v0.1.9 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(proc_macro_span)]
[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 `singleton-attr-proc-macro` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "cec16e0a70ba07aa9603c475e3b59041f2d104723d438bd4d6f4e891dc2fee07", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cec16e0a70ba07aa9603c475e3b59041f2d104723d438bd4d6f4e891dc2fee07", kill_on_drop: false }`
[INFO] [stdout] cec16e0a70ba07aa9603c475e3b59041f2d104723d438bd4d6f4e891dc2fee07
