[INFO] cloning repository https://github.com/hnkz/runtime_experiment
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/hnkz/runtime_experiment" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhnkz%2Fruntime_experiment", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhnkz%2Fruntime_experiment'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d7c53f1011264ecc92fb890b2e228291a8381563
[INFO] testing hnkz/runtime_experiment against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhnkz%2Fruntime_experiment" "/workspace/builds/worker-13/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/hnkz/runtime_experiment on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/hnkz/runtime_experiment
[INFO] finished tweaking git repo https://github.com/hnkz/runtime_experiment
[INFO] tweaked toml for git repo https://github.com/hnkz/runtime_experiment written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/hnkz/runtime_experiment already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "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" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5d6395fb6e26263ffab5985d9a7560c15bc99e39ebd2690700374e2b9d8ba23f
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "5d6395fb6e26263ffab5985d9a7560c15bc99e39ebd2690700374e2b9d8ba23f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5d6395fb6e26263ffab5985d9a7560c15bc99e39ebd2690700374e2b9d8ba23f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5d6395fb6e26263ffab5985d9a7560c15bc99e39ebd2690700374e2b9d8ba23f", kill_on_drop: false }`
[INFO] [stdout] 5d6395fb6e26263ffab5985d9a7560c15bc99e39ebd2690700374e2b9d8ba23f
[INFO] running `Command { std: "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" "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" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 11a60092022418beb8e1e53358be8ecc9b2dffee2961fe3d9ae383e9d3fd1e5e
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "11a60092022418beb8e1e53358be8ecc9b2dffee2961fe3d9ae383e9d3fd1e5e", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.60
[INFO] [stderr]    Compiling autocfg v0.1.5
[INFO] [stderr]    Compiling spin v0.5.0
[INFO] [stderr]    Compiling syn v0.15.39
[INFO] [stderr]    Compiling rand_core v0.4.0
[INFO] [stderr]    Compiling cfg-if v0.1.9
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling proc-macro-nested v0.1.3
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling futures v0.1.28
[INFO] [stderr]    Compiling arrayvec v0.4.11
[INFO] [stderr]    Compiling log v0.4.7
[INFO] [stderr]    Compiling nodrop v0.1.13
[INFO] [stderr]    Compiling cc v1.0.37
[INFO] [stderr]    Compiling failure_derive v0.1.5
[INFO] [stderr]    Compiling async-ready v3.0.0
[INFO] [stderr]    Compiling async-datagram v3.0.0
[INFO] [stderr]    Compiling async-datagram v2.2.0
[INFO] [stderr]    Compiling rustc-demangle v0.1.15
[INFO] [stderr]    Compiling lazy_static v1.3.0
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/async-datagram-2.2.0/src/lib.rs:43:1
[INFO] [stdout]    |
[INFO] [stdout] 43 | #![feature(futures_api)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `async-datagram` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "11a60092022418beb8e1e53358be8ecc9b2dffee2961fe3d9ae383e9d3fd1e5e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "11a60092022418beb8e1e53358be8ecc9b2dffee2961fe3d9ae383e9d3fd1e5e", kill_on_drop: false }`
[INFO] [stdout] 11a60092022418beb8e1e53358be8ecc9b2dffee2961fe3d9ae383e9d3fd1e5e