[INFO] fetching crate descent_ipopt 0.5.0...
[INFO] testing descent_ipopt-0.5.0 against beta-2021-09-08 for beta-1.56-1
[INFO] extracting crate descent_ipopt 0.5.0 into /workspace/builds/worker-93/source
[INFO] validating manifest of crates.io crate descent_ipopt 0.5.0 on toolchain beta-2021-09-08
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-09-08" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate descent_ipopt 0.5.0
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate descent_ipopt 0.5.0
[INFO] tweaked toml for crates.io crate descent_ipopt 0.5.0 written to /workspace/builds/worker-93/source/Cargo.toml
[INFO] crate crates.io crate descent_ipopt 0.5.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-09-08" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded descent_macro v0.5.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-93/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-93/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-09-08" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d17640071ef679bc3b77b78bc9ee51b0fc68cabaa1745837fedbcdcc94f34b2d
[INFO] running `Command { std: "docker" "start" "-a" "d17640071ef679bc3b77b78bc9ee51b0fc68cabaa1745837fedbcdcc94f34b2d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d17640071ef679bc3b77b78bc9ee51b0fc68cabaa1745837fedbcdcc94f34b2d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d17640071ef679bc3b77b78bc9ee51b0fc68cabaa1745837fedbcdcc94f34b2d", kill_on_drop: false }`
[INFO] [stdout] d17640071ef679bc3b77b78bc9ee51b0fc68cabaa1745837fedbcdcc94f34b2d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-93/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-93/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" "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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-09-08" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ed0d478b5fcbb89e1ccf26b9c0fc73a8d919f4a60009e3eb6fbb8ee998992b8f
[INFO] running `Command { std: "docker" "start" "-a" "ed0d478b5fcbb89e1ccf26b9c0fc73a8d919f4a60009e3eb6fbb8ee998992b8f", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.60
[INFO] [stderr]    Compiling libc v0.2.84
[INFO] [stderr]    Compiling quote v1.0.8
[INFO] [stderr]    Compiling snafu-derive v0.6.10
[INFO] [stderr]    Compiling snafu v0.6.10
[INFO] [stderr]    Compiling descent v0.5.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/descent-0.5.0/src/lib.rs:9:1
[INFO] [stdout]   |
[INFO] [stdout] 9 | #![feature(test)] // enable benchmarking
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `descent` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "ed0d478b5fcbb89e1ccf26b9c0fc73a8d919f4a60009e3eb6fbb8ee998992b8f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ed0d478b5fcbb89e1ccf26b9c0fc73a8d919f4a60009e3eb6fbb8ee998992b8f", kill_on_drop: false }`
[INFO] [stdout] ed0d478b5fcbb89e1ccf26b9c0fc73a8d919f4a60009e3eb6fbb8ee998992b8f