[INFO] fetching crate aktoro-channel 0.1.0-alpha.8...
[INFO] testing aktoro-channel-0.1.0-alpha.8 against 1.47.0 for beta-1.48-1
[INFO] extracting crate aktoro-channel 0.1.0-alpha.8 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate aktoro-channel 0.1.0-alpha.8 on toolchain 1.47.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate aktoro-channel 0.1.0-alpha.8
[INFO] finished tweaking crates.io crate aktoro-channel 0.1.0-alpha.8
[INFO] tweaked toml for crates.io crate aktoro-channel 0.1.0-alpha.8 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.47.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "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" "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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1680936a9e874d49fbed5ca7037fbd1715a1229bec6c61a4365009a2b7ef36eb
[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" "1680936a9e874d49fbed5ca7037fbd1715a1229bec6c61a4365009a2b7ef36eb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1680936a9e874d49fbed5ca7037fbd1715a1229bec6c61a4365009a2b7ef36eb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1680936a9e874d49fbed5ca7037fbd1715a1229bec6c61a4365009a2b7ef36eb", kill_on_drop: false }`
[INFO] [stdout] 1680936a9e874d49fbed5ca7037fbd1715a1229bec6c61a4365009a2b7ef36eb
[INFO] running `Command { std: "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" "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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 848db0cf654b4d4d8739d2d66aee8e4cfbc74a0f53bc6d34805fa111398121f0
[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" "848db0cf654b4d4d8739d2d66aee8e4cfbc74a0f53bc6d34805fa111398121f0", kill_on_drop: false }`
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling crossbeam-utils v0.6.6
[INFO] [stderr]    Compiling crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling aktoro-channel v0.1.0-alpha.8 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.80s
[INFO] running `Command { std: "docker" "inspect" "848db0cf654b4d4d8739d2d66aee8e4cfbc74a0f53bc6d34805fa111398121f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "848db0cf654b4d4d8739d2d66aee8e4cfbc74a0f53bc6d34805fa111398121f0", kill_on_drop: false }`
[INFO] [stdout] 848db0cf654b4d4d8739d2d66aee8e4cfbc74a0f53bc6d34805fa111398121f0
[INFO] running `Command { std: "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" "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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.47.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b76bdcb24fdafc3fb4dd13e955f174fea24360770600930e6c8e8a1ad8c52987
[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" "b76bdcb24fdafc3fb4dd13e955f174fea24360770600930e6c8e8a1ad8c52987", kill_on_drop: false }`
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling futures v0.1.30
[INFO] [stderr]    Compiling pin-utils v0.1.0
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling proc-macro2 v1.0.24
[INFO] [stderr]    Compiling syn v1.0.44
[INFO] [stderr]    Compiling async-ready v3.0.0
[INFO] [stderr]    Compiling async-datagram v3.0.0
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling smallvec v0.6.13
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling crossbeam-queue v0.2.3
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling net2 v0.2.35
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling crossbeam v0.7.3
[INFO] [stderr]    Compiling mio v0.6.22
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling mio-uds v0.6.8
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.18
[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/futures-util-preview-0.3.0-alpha.18/src/lib.rs:4:38
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![cfg_attr(feature = "async-await", feature(async_await))]
[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 `futures-util-preview`.
[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 `Command { std: "docker" "inspect" "b76bdcb24fdafc3fb4dd13e955f174fea24360770600930e6c8e8a1ad8c52987", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b76bdcb24fdafc3fb4dd13e955f174fea24360770600930e6c8e8a1ad8c52987", kill_on_drop: false }`
[INFO] [stdout] b76bdcb24fdafc3fb4dd13e955f174fea24360770600930e6c8e8a1ad8c52987
