[INFO] fetching crate kf-socket 2.0.0...
[INFO] testing kf-socket-2.0.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate kf-socket 2.0.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate kf-socket 2.0.0 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate kf-socket 2.0.0
[INFO] finished tweaking crates.io crate kf-socket 2.0.0
[INFO] tweaked toml for crates.io crate kf-socket 2.0.0 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate crates.io crate kf-socket 2.0.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a3b19d1ffa0024b9c053ba2abb2f103ddfbe81c2f27ab95c0ce94ff7dd5aa890
[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" "a3b19d1ffa0024b9c053ba2abb2f103ddfbe81c2f27ab95c0ce94ff7dd5aa890", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a3b19d1ffa0024b9c053ba2abb2f103ddfbe81c2f27ab95c0ce94ff7dd5aa890", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a3b19d1ffa0024b9c053ba2abb2f103ddfbe81c2f27ab95c0ce94ff7dd5aa890", kill_on_drop: false }`
[INFO] [stdout] a3b19d1ffa0024b9c053ba2abb2f103ddfbe81c2f27ab95c0ce94ff7dd5aa890
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f96363492261cb6c0702e49dbda725f0d624cba4106e147c532327e1ede32570
[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" "f96363492261cb6c0702e49dbda725f0d624cba4106e147c532327e1ede32570", kill_on_drop: false }`
[INFO] [stderr] warning: invalid feature `cli` in required-features of target `file_send`: `cli` is not present in [features] section
[INFO] [stderr]    Compiling libc v0.2.70
[INFO] [stderr]    Compiling syn v1.0.22
[INFO] [stderr]    Compiling cc v1.0.53
[INFO] [stderr]    Compiling futures-io v0.3.5
[INFO] [stderr]    Compiling pin-project-lite v0.1.5
[INFO] [stderr]    Compiling nix v0.16.1
[INFO] [stderr]    Compiling crc32c v0.4.0
[INFO] [stderr]    Compiling futures-task v0.3.5
[INFO] [stderr]    Compiling proc-macro2 v1.0.13
[INFO] [stderr]    Compiling owning_ref v0.3.3
[INFO] [stderr]    Compiling kv-log-macro v1.0.5
[INFO] [stderr]    Compiling content_inspector v0.2.4
[INFO] [stderr]    Compiling flv-types v0.1.0
[INFO] [stderr]    Compiling num-derive v0.2.5
[INFO] [stderr]    Compiling kf-protocol-derive v0.1.0
[INFO] [stderr]    Compiling tokio v0.2.21
[INFO] [stderr]    Compiling quote v1.0.5
[INFO] [stderr]    Compiling ring v0.16.13
[INFO] [stderr]    Compiling tokio-util v0.3.1
[INFO] [stderr]    Compiling time v0.1.43
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling net2 v0.2.34
[INFO] [stderr]    Compiling parking_lot_core v0.7.2
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling async-task v1.3.1
[INFO] [stderr]    Compiling memmap v0.7.0
[INFO] [stderr]    Compiling rand v0.4.6
[INFO] [stderr]    Compiling env_logger v0.6.2
[INFO] [stderr]    Compiling parking_lot v0.10.2
[INFO] [stderr]    Compiling mio v0.6.22
[INFO] [stderr]    Compiling chrono v0.4.11
[INFO] [stderr]    Compiling parking_lot_core v0.2.14
[INFO] [stderr]    Compiling parking_lot v0.4.8
[INFO] [stderr]    Compiling chashmap v2.2.2
[INFO] [stderr]    Compiling mio-uds v0.6.8
[INFO] [stderr]    Compiling flv-util v0.1.1
[INFO] [stderr]    Compiling webpki v0.21.2
[INFO] [stderr]    Compiling sct v0.6.0
[INFO] [stderr]    Compiling webpki-roots v0.19.0
[INFO] [stderr]    Compiling rustls v0.17.0
[INFO] [stderr]    Compiling pin-project-internal v0.4.16
[INFO] [stderr]    Compiling futures-macro v0.3.5
[INFO] [stderr]    Compiling serde_derive v1.0.110
[INFO] [stderr]    Compiling paste-impl v0.1.12
[INFO] [stderr]    Compiling async-trait v0.1.31
[INFO] [stderr]    Compiling async-test-derive v1.0.0
[INFO] [stderr]    Compiling paste v0.1.12
[INFO] [stderr]    Compiling pin-project v0.4.16
[INFO] [stderr]    Compiling futures-util v0.3.5
[INFO] [stderr]    Compiling serde v1.0.110
[INFO] [stderr]    Compiling futures-executor v0.3.5
[INFO] [stderr]    Compiling broadcaster v1.0.0
[INFO] [stderr]    Compiling async-std v1.5.0
[INFO] [stderr]    Compiling futures v0.3.5
[INFO] [stderr]    Compiling async-tls v0.7.0
[INFO] [stderr]    Compiling kf-protocol-core v0.1.1
[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/kf-protocol-core-0.1.1/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(specialization)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `kf-protocol-core`
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[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" "f96363492261cb6c0702e49dbda725f0d624cba4106e147c532327e1ede32570", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f96363492261cb6c0702e49dbda725f0d624cba4106e147c532327e1ede32570", kill_on_drop: false }`
[INFO] [stdout] f96363492261cb6c0702e49dbda725f0d624cba4106e147c532327e1ede32570