[INFO] crate mantle-build 0.2.2 is already in cache
[INFO] testing mantle-build-0.2.2 against 1.44.0 for beta-1.45-1
[INFO] extracting crate mantle-build 0.2.2 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate mantle-build 0.2.2 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 mantle-build 0.2.2
[INFO] finished tweaking crates.io crate mantle-build 0.2.2
[INFO] tweaked toml for crates.io crate mantle-build 0.2.2 written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate crates.io crate mantle-build 0.2.2 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] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] a6c4697c7a775d51f770ff90b3856c10b75700923d5d507abfa66ea30393ad10
[INFO] running `"docker" "start" "-a" "a6c4697c7a775d51f770ff90b3856c10b75700923d5d507abfa66ea30393ad10"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling syn v0.15.39
[INFO] [stderr]    Compiling arrayvec v0.4.10
[INFO] [stderr]    Compiling autocfg v0.1.4
[INFO] [stderr]    Compiling cc v1.0.37
[INFO] [stderr]    Compiling serde v1.0.94
[INFO] [stderr]    Compiling unicode-segmentation v1.3.0
[INFO] [stderr]    Compiling winapi v0.3.7
[INFO] [stderr]    Compiling rustc-demangle v0.1.15
[INFO] [stderr]    Compiling leb128 v0.2.4
[INFO] [stderr]    Compiling wasmparser v0.30.0
[INFO] [stderr]    Compiling log v0.4.6
[INFO] [stderr]    Compiling crc32fast v1.2.0
[INFO] [stderr]    Compiling idna v0.1.5
[INFO] [stderr]    Compiling crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling quote v0.6.12
[INFO] [stderr]    Compiling num_cpus v1.10.1
[INFO] [stderr]    Compiling libflate v0.1.25
[INFO] [stderr]    Compiling heck v0.3.1
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]    Compiling url v1.7.2
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.1
[INFO] [stderr]    Compiling backtrace-sys v0.1.30
[INFO] [stderr]    Compiling crossbeam-deque v0.6.3
[INFO] [stderr]    Compiling rayon-core v1.5.0
[INFO] [stderr]    Compiling num-traits v0.1.43
[INFO] [stderr]    Compiling cgmath v0.16.1
[INFO] [stderr]    Compiling backtrace v0.3.32
[INFO] [stderr]    Compiling rayon v1.1.0
[INFO] [stderr]    Compiling id-arena v2.2.1
[INFO] [stderr]    Compiling winconsole v0.10.0
[INFO] [stderr]    Compiling colored v1.8.0
[INFO] [stderr]    Compiling synstructure v0.10.2
[INFO] [stderr]    Compiling serde_derive v1.0.94
[INFO] [stderr]    Compiling failure_derive v0.1.5
[INFO] [stderr]    Compiling proc-macro-hack v0.5.8
[INFO] [stderr]    Compiling walrus-macro v0.8.0
[INFO] [stderr]    Compiling proc-quote-impl v0.2.2
[INFO] [stderr]    Compiling failure v0.1.5
[INFO] [stderr]    Compiling proc-quote v0.2.2
[INFO] [stderr]    Compiling walrus v0.8.0
[INFO] [stderr]    Compiling serde_json v1.0.40
[INFO] [stderr]    Compiling toml v0.5.1
[INFO] [stderr]    Compiling mantle-rpc v0.1.1
[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/mantle-rpc-0.1.1/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(box_syntax)]
[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 `mantle-rpc`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "a6c4697c7a775d51f770ff90b3856c10b75700923d5d507abfa66ea30393ad10"`
[INFO] running `"docker" "rm" "-f" "a6c4697c7a775d51f770ff90b3856c10b75700923d5d507abfa66ea30393ad10"`
[INFO] [stdout] a6c4697c7a775d51f770ff90b3856c10b75700923d5d507abfa66ea30393ad10