[INFO] fetching crate nature_db 0.7.0...
[INFO] testing nature_db-0.7.0 against 1.44.0 for beta-1.45-1
[INFO] extracting crate nature_db 0.7.0 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate nature_db 0.7.0 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 nature_db 0.7.0
[INFO] finished tweaking crates.io crate nature_db 0.7.0
[INFO] tweaked toml for crates.io crate nature_db 0.7.0 written to /workspace/builds/worker-3/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-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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] a3a4c3f11a23c09d4ad279fff666c9b4f1c2a8a5270e008e12b7992bb2b531fb
[INFO] running `"docker" "start" "-a" "a3a4c3f11a23c09d4ad279fff666c9b4f1c2a8a5270e008e12b7992bb2b531fb"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling syn v1.0.30
[INFO] [stderr]    Compiling lru_time_cache v0.10.0
[INFO] [stderr]    Compiling mysqlclient-sys v0.2.4
[INFO] [stderr]    Compiling uuid v0.8.1
[INFO] [stderr]    Compiling synstructure v0.12.3
[INFO] [stderr]    Compiling pin-project-internal v0.4.19
[INFO] [stderr]    Compiling futures-macro v0.3.5
[INFO] [stderr]    Compiling derive_more v0.99.7
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling enum-as-inner v0.3.2
[INFO] [stderr]    Compiling async-trait v0.1.33
[INFO] [stderr]    Compiling actix-macros v0.1.2
[INFO] [stderr]    Compiling actix_derive v0.5.0
[INFO] [stderr]    Compiling serde_derive v1.0.111
[INFO] [stderr]    Compiling diesel_derives v1.4.1
[INFO] [stderr]    Compiling failure v0.1.8
[INFO] [stderr]    Compiling pin-project v0.4.19
[INFO] [stderr]    Compiling futures-util v0.3.5
[INFO] [stderr]    Compiling actix-threadpool v0.3.2
[INFO] [stderr]    Compiling diesel v1.4.4
[INFO] [stderr]    Compiling futures-executor v0.3.5
[INFO] [stderr]    Compiling h2 v0.2.5
[INFO] [stderr]    Compiling actix-rt v1.1.1
[INFO] [stderr]    Compiling actix-service v1.0.5
[INFO] [stderr]    Compiling futures v0.3.5
[INFO] [stderr]    Compiling trust-dns-proto v0.18.0-alpha.2
[INFO] [stderr]    Compiling actix-utils v1.0.6
[INFO] [stderr]    Compiling trust-dns-resolver v0.18.0-alpha.2
[INFO] [stderr]    Compiling hyper v0.13.6
[INFO] [stderr]    Compiling actix-connect v1.0.2
[INFO] [stderr]    Compiling actix-http v1.0.1
[INFO] [stderr]    Compiling hyper-tls v0.4.1
[INFO] [stderr]    Compiling reqwest v0.10.6
[INFO] [stderr]    Compiling actix v0.9.0
[INFO] [stderr]    Compiling nature_common v0.7.0
[INFO] [stderr]    Compiling nature_db v0.7.0 (/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(rustc_private)]
[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 `nature_db`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "a3a4c3f11a23c09d4ad279fff666c9b4f1c2a8a5270e008e12b7992bb2b531fb"`
[INFO] running `"docker" "rm" "-f" "a3a4c3f11a23c09d4ad279fff666c9b4f1c2a8a5270e008e12b7992bb2b531fb"`
[INFO] [stdout] a3a4c3f11a23c09d4ad279fff666c9b4f1c2a8a5270e008e12b7992bb2b531fb