[INFO] fetching crate descent_ipopt 0.4.0...
[INFO] testing descent_ipopt-0.4.0 against 1.44.0 for beta-1.45-1
[INFO] extracting crate descent_ipopt 0.4.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate descent_ipopt 0.4.0 on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate descent_ipopt 0.4.0
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate descent_ipopt 0.4.0
[INFO] tweaked toml for crates.io crate descent_ipopt 0.4.0 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate crates.io crate descent_ipopt 0.4.0 already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.44.0" "build" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] bdce9a2d51ffdc8d523f28b6f056130305583cc767823e05a374d9973500d6d0
[INFO] running `"docker" "start" "-a" "bdce9a2d51ffdc8d523f28b6f056130305583cc767823e05a374d9973500d6d0"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling proc-macro2 v1.0.17
[INFO] [stderr]    Compiling syn v1.0.27
[INFO] [stderr]    Compiling quote v1.0.6
[INFO] [stderr]    Compiling snafu-derive v0.6.8
[INFO] [stderr]    Compiling snafu v0.6.8
[INFO] [stderr]    Compiling descent v0.4.0
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/descent-0.4.0/src/lib.rs:9:1
[INFO] [stderr]   |
[INFO] [stderr] 9 | #![feature(test)] // enable benchmarking
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `descent`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "bdce9a2d51ffdc8d523f28b6f056130305583cc767823e05a374d9973500d6d0"`
[INFO] running `"docker" "rm" "-f" "bdce9a2d51ffdc8d523f28b6f056130305583cc767823e05a374d9973500d6d0"`
[INFO] [stdout] bdce9a2d51ffdc8d523f28b6f056130305583cc767823e05a374d9973500d6d0