[INFO] crate rcmath 0.0.1 is already in cache
[INFO] testing rcmath-0.0.1 against 1.44.0 for beta-1.45-1
[INFO] extracting crate rcmath 0.0.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate rcmath 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 rcmath 0.0.1
[INFO] finished tweaking crates.io crate rcmath 0.0.1
[INFO] tweaked toml for crates.io crate rcmath 0.0.1 written to /workspace/builds/worker-4/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-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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] de955ece0e6a24cea798e622dc05074649b0588d221c3bf9f82aebb40d4926ed
[INFO] running `"docker" "start" "-a" "de955ece0e6a24cea798e622dc05074649b0588d221c3bf9f82aebb40d4926ed"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling autocfg v1.0.0
[INFO] [stderr]    Compiling num-traits v0.2.11
[INFO] [stderr]    Compiling num-integer v0.1.42
[INFO] [stderr]    Compiling num-bigint v0.2.6
[INFO] [stderr]    Compiling rcmath 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:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(step_trait)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unnecessary parentheses around block return value
[INFO] [stderr]   --> src/big_num.rs:58:9
[INFO] [stderr]    |
[INFO] [stderr] 58 |         (BigNum::new_empty()..self.clone())
[INFO] [stderr]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_parens)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Add`
[INFO] [stderr]  --> src/math.rs:3:16
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::ops::{Add, Div, Mul, Rem};
[INFO] [stderr]   |                ^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error; 2 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `rcmath`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "de955ece0e6a24cea798e622dc05074649b0588d221c3bf9f82aebb40d4926ed"`
[INFO] running `"docker" "rm" "-f" "de955ece0e6a24cea798e622dc05074649b0588d221c3bf9f82aebb40d4926ed"`
[INFO] [stdout] de955ece0e6a24cea798e622dc05074649b0588d221c3bf9f82aebb40d4926ed