[INFO] crate aktoro 0.1.0-alpha.4 is already in cache
[INFO] testing aktoro-0.1.0-alpha.4 against 1.44.0 for beta-1.45-1
[INFO] extracting crate aktoro 0.1.0-alpha.4 into /workspace/builds/worker-13/source
[INFO] validating manifest of crates.io crate aktoro 0.1.0-alpha.4 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 aktoro 0.1.0-alpha.4
[INFO] finished tweaking crates.io crate aktoro 0.1.0-alpha.4
[INFO] tweaked toml for crates.io crate aktoro 0.1.0-alpha.4 written to /workspace/builds/worker-13/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-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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] 773775285a5cf6a350befc792ac18c16d73c88e6b615247d1516106977f2d053
[INFO] running `"docker" "start" "-a" "773775285a5cf6a350befc792ac18c16d73c88e6b615247d1516106977f2d053"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling autocfg v0.1.7
[INFO] [stderr]    Compiling proc-macro2 v1.0.18
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling rand_xoshiro v0.2.0
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling quote v1.0.6
[INFO] [stderr]    Compiling syn v1.0.30
[INFO] [stderr]    Compiling futures-executor-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling aktoro-context v0.1.0-alpha.4
[INFO] [stderr]    Compiling futures-preview v0.3.0-alpha.19
[INFO] [stderr]    Compiling runtime-raw v0.3.0-alpha.5
[INFO] [stderr]    Compiling pin-project-internal v0.4.17
[INFO] [stderr]    Compiling runtime-attributes v0.3.0-alpha.6
[INFO] [stderr]    Compiling pin-project v0.4.17
[INFO] [stderr]    Compiling runtime v0.3.0-alpha.8
[INFO] [stderr]    Compiling aktoro-runtime v0.1.0-alpha.4
[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/aktoro-runtime-0.1.0-alpha.4/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(async_await)]
[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 `aktoro-runtime`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "773775285a5cf6a350befc792ac18c16d73c88e6b615247d1516106977f2d053"`
[INFO] running `"docker" "rm" "-f" "773775285a5cf6a350befc792ac18c16d73c88e6b615247d1516106977f2d053"`
[INFO] [stdout] 773775285a5cf6a350befc792ac18c16d73c88e6b615247d1516106977f2d053