[INFO] fetching crate rustc-ap-rustc_data_structures 727.0.0...
[INFO] testing rustc-ap-rustc_data_structures-727.0.0 against beta-2026-04-21 for beta-1.96-2
[INFO] extracting crate rustc-ap-rustc_data_structures 727.0.0 into /workspace/builds/worker-7-tc2/source
[INFO] started tweaking crates.io crate rustc-ap-rustc_data_structures 727.0.0
[INFO] finished tweaking crates.io crate rustc-ap-rustc_data_structures 727.0.0
[INFO] tweaked toml for crates.io crate rustc-ap-rustc_data_structures 727.0.0 written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate rustc-ap-rustc_data_structures 727.0.0 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 100 packages to latest compatible versions
[INFO] [stderr]       Adding bitflags v1.3.2 (available: v2.11.1)
[INFO] [stderr]       Adding cfg-if v0.1.10 (available: v1.0.4)
[INFO] [stderr]       Adding indexmap v1.9.3 (available: v2.14.0)
[INFO] [stderr]       Adding measureme v9.1.2 (available: v12.0.3)
[INFO] [stderr]       Adding memmap2 v0.2.3 (available: v0.9.10)
[INFO] [stderr]       Adding parking_lot v0.11.2 (available: v0.12.5)
[INFO] [stderr]       Adding rustc-hash v1.1.0 (available: v2.1.2)
[INFO] [stderr]       Adding rustc-rayon v0.3.2 (available: v0.5.1)
[INFO] [stderr]       Adding rustc-rayon-core v0.3.2 (available: v0.5.1)
[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-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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] 4691aaf0305f39efae297ad7d2013a81ce998e5c5b4e9af8c9ba070ca8021599
[INFO] running `Command { std: "docker" "start" "-a" "4691aaf0305f39efae297ad7d2013a81ce998e5c5b4e9af8c9ba070ca8021599", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4691aaf0305f39efae297ad7d2013a81ce998e5c5b4e9af8c9ba070ca8021599", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4691aaf0305f39efae297ad7d2013a81ce998e5c5b4e9af8c9ba070ca8021599", kill_on_drop: false }`
[INFO] [stdout] 4691aaf0305f39efae297ad7d2013a81ce998e5c5b4e9af8c9ba070ca8021599
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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] a9dd53e8a30173ad5f1fca4fc6bdca3f3bc1053ac6923f4eb796fa21a4fcf843
[INFO] running `Command { std: "docker" "start" "-a" "a9dd53e8a30173ad5f1fca4fc6bdca3f3bc1053ac6923f4eb796fa21a4fcf843", kill_on_drop: false }`
[INFO] [stderr]    Compiling object v0.37.3
[INFO] [stderr]    Compiling smallvec v1.15.1
[INFO] [stderr]    Compiling parking_lot_core v0.8.6
[INFO] [stderr]    Compiling instant v0.1.13
[INFO] [stderr]    Compiling indexmap v1.9.3
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling rustc-rayon-core v0.3.2
[INFO] [stderr]    Compiling syn v2.0.117
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/smallvec-1.15.1/src/lib.rs:96:37
[INFO] [stdout]    |
[INFO] [stdout] 96 | #![cfg_attr(feature = "may_dangle", feature(dropck_eyepatch))]
[INFO] [stdout]    |                                     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling num_cpus v1.17.0
[INFO] [stderr]    Compiling stacker v0.1.24
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr]    Compiling rustix v1.1.4
[INFO] [stderr] error: could not compile `smallvec` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "a9dd53e8a30173ad5f1fca4fc6bdca3f3bc1053ac6923f4eb796fa21a4fcf843", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a9dd53e8a30173ad5f1fca4fc6bdca3f3bc1053ac6923f4eb796fa21a4fcf843", kill_on_drop: false }`
[INFO] [stdout] a9dd53e8a30173ad5f1fca4fc6bdca3f3bc1053ac6923f4eb796fa21a4fcf843
