[INFO] fetching crate rio_rt 0.1.0-alpha.2...
[INFO] testing rio_rt-0.1.0-alpha.2 against beta-2026-04-21 for beta-1.96-2
[INFO] extracting crate rio_rt 0.1.0-alpha.2 into /workspace/builds/worker-5-tc2/source
[INFO] started tweaking crates.io crate rio_rt 0.1.0-alpha.2
[INFO] finished tweaking crates.io crate rio_rt 0.1.0-alpha.2
[INFO] tweaked toml for crates.io crate rio_rt 0.1.0-alpha.2 written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate rio_rt 0.1.0-alpha.2 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 1 package to latest compatible version
[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-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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8da03ae6e8809ab406967f1884388456d6a1aaa7b19fd61caf5c71d7d5b4652b
[INFO] running `Command { std: "docker" "start" "-a" "8da03ae6e8809ab406967f1884388456d6a1aaa7b19fd61caf5c71d7d5b4652b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8da03ae6e8809ab406967f1884388456d6a1aaa7b19fd61caf5c71d7d5b4652b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8da03ae6e8809ab406967f1884388456d6a1aaa7b19fd61caf5c71d7d5b4652b", kill_on_drop: false }`
[INFO] [stdout] 8da03ae6e8809ab406967f1884388456d6a1aaa7b19fd61caf5c71d7d5b4652b
[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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] dff85a1edbdd2756f71f54a5ada0ff0ddb8ef0879b526ada02e79394214cf809
[INFO] running `Command { std: "docker" "start" "-a" "dff85a1edbdd2756f71f54a5ada0ff0ddb8ef0879b526ada02e79394214cf809", kill_on_drop: false }`
[INFO] [stderr]    Compiling rio_rt v0.1.0-alpha.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> src/lib.rs:10:1
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![feature(once_cell)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `once_cell` has been stable since 1.70.0 and no longer requires an attribute to enable
[INFO] [stdout]   --> src/lib.rs:10:12
[INFO] [stdout]    |
[INFO] [stdout] 10 | #![feature(once_cell)]
[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 `rio_rt` (lib) due to 1 previous error; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "dff85a1edbdd2756f71f54a5ada0ff0ddb8ef0879b526ada02e79394214cf809", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dff85a1edbdd2756f71f54a5ada0ff0ddb8ef0879b526ada02e79394214cf809", kill_on_drop: false }`
[INFO] [stdout] dff85a1edbdd2756f71f54a5ada0ff0ddb8ef0879b526ada02e79394214cf809
