[INFO] crate no_mutex 0.0.1 is already in cache
[INFO] testing no_mutex-0.0.1 against 1.44.0 for beta-1.45-1
[INFO] extracting crate no_mutex 0.0.1 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate no_mutex 0.0.1 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 no_mutex 0.0.1
[INFO] finished tweaking crates.io crate no_mutex 0.0.1
[INFO] tweaked toml for crates.io crate no_mutex 0.0.1 written to /workspace/builds/worker-0/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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] 92b54bdc008006b02a978287b3b6a669c895a924f76a2e5d3b9688ed0c0f0fdd
[INFO] running `"docker" "start" "-a" "92b54bdc008006b02a978287b3b6a669c895a924f76a2e5d3b9688ed0c0f0fdd"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling no_mutex v0.0.1 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(const_fn)]
[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 `no_mutex`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "92b54bdc008006b02a978287b3b6a669c895a924f76a2e5d3b9688ed0c0f0fdd"`
[INFO] running `"docker" "rm" "-f" "92b54bdc008006b02a978287b3b6a669c895a924f76a2e5d3b9688ed0c0f0fdd"`
[INFO] [stdout] 92b54bdc008006b02a978287b3b6a669c895a924f76a2e5d3b9688ed0c0f0fdd