[INFO] fetching crate nimiq-rpc-server 0.2.0...
[INFO] testing nimiq-rpc-server-0.2.0 against 1.44.0 for beta-1.45-1
[INFO] extracting crate nimiq-rpc-server 0.2.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate nimiq-rpc-server 0.2.0 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 nimiq-rpc-server 0.2.0
[INFO] finished tweaking crates.io crate nimiq-rpc-server 0.2.0
[INFO] tweaked toml for crates.io crate nimiq-rpc-server 0.2.0 written to /workspace/builds/worker-2/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-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] [stdout] 29652d52abe4ce58fadc22f8396eb6e90692f44844eba20751b84cd9c2274ead
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "29652d52abe4ce58fadc22f8396eb6e90692f44844eba20751b84cd9c2274ead"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling arrayvec v0.4.12
[INFO] [stderr]    Compiling subtle v2.2.3
[INFO] [stderr]    Compiling stable_deref_trait v1.1.1
[INFO] [stderr]    Compiling nodrop v0.1.14
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling scopeguard v0.3.3
[INFO] [stderr]    Compiling unicode-xid v0.0.4
[INFO] [stderr]    Compiling hex v0.3.2
[INFO] [stderr]    Compiling nimiq-macros v0.2.0
[INFO] [stderr]    Compiling quote v0.3.15
[INFO] [stderr]    Compiling zeroize v1.1.0
[INFO] [stderr]    Compiling nimiq-collections v0.2.0
[INFO] [stderr]    Compiling bit-vec v0.5.1
[INFO] [stderr]    Compiling atomic v0.4.5
[INFO] [stderr]    Compiling supercow v0.1.0
[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/nimiq-collections-0.2.0/src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(box_into_raw_non_null)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[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/nimiq-collections-0.2.0/src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(specialization)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]    Compiling utf-8 v0.7.5
[INFO] [stderr]    Compiling weak-table v0.2.3
[INFO] [stderr]    Compiling json v0.11.15
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: could not compile `nimiq-collections`.
[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" "29652d52abe4ce58fadc22f8396eb6e90692f44844eba20751b84cd9c2274ead"`
[INFO] running `"docker" "rm" "-f" "29652d52abe4ce58fadc22f8396eb6e90692f44844eba20751b84cd9c2274ead"`
[INFO] [stdout] 29652d52abe4ce58fadc22f8396eb6e90692f44844eba20751b84cd9c2274ead