[INFO] cloning repository https://github.com/codebam/chatserver-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/codebam/chatserver-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcodebam%2Fchatserver-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcodebam%2Fchatserver-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ccbaf51e3d3b5eaa1d7bc76b95398ff1a9183b2c
[INFO] testing codebam/chatserver-rust against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcodebam%2Fchatserver-rust" "/workspace/builds/worker-9/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-9/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/codebam/chatserver-rust 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 git repo https://github.com/codebam/chatserver-rust
[INFO] finished tweaking git repo https://github.com/codebam/chatserver-rust
[INFO] tweaked toml for git repo https://github.com/codebam/chatserver-rust written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate git repo https://github.com/codebam/chatserver-rust 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] d3a03297ae4e7ee0e40d3509dac78c1caea7a4383c4bb6b72e7d88a4cd4f76e2
[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" "d3a03297ae4e7ee0e40d3509dac78c1caea7a4383c4bb6b72e7d88a4cd4f76e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d3a03297ae4e7ee0e40d3509dac78c1caea7a4383c4bb6b72e7d88a4cd4f76e2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d3a03297ae4e7ee0e40d3509dac78c1caea7a4383c4bb6b72e7d88a4cd4f76e2", kill_on_drop: false }`
[INFO] [stdout] d3a03297ae4e7ee0e40d3509dac78c1caea7a4383c4bb6b72e7d88a4cd4f76e2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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] d977ea4923050b2e0892d5821acc0f559de5e9d1d7997ae6e1c4a6df84c782a5
[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" "d977ea4923050b2e0892d5821acc0f559de5e9d1d7997ae6e1c4a6df84c782a5", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.4
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling byteorder v1.3.2
[INFO] [stderr]    Compiling futures-core v0.3.1
[INFO] [stderr]    Compiling futures-task v0.3.1
[INFO] [stderr]    Compiling async-task v1.0.0
[INFO] [stderr]    Compiling getrandom v0.1.12
[INFO] [stderr]    Compiling net2 v0.2.33
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.2
[INFO] [stderr]    Compiling futures-channel v0.3.1
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling async-macros v1.0.0
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling crossbeam-deque v0.7.1
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling rand v0.7.2
[INFO] [stderr]    Compiling mio v0.6.19
[INFO] [stderr]    Compiling kv-log-macro v1.0.4
[INFO] [stderr]    Compiling block-buffer v0.7.3
[INFO] [stderr]    Compiling sha2 v0.8.0
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]    Compiling mio-uds v0.6.7
[INFO] [stderr]    Compiling proc-macro-hack v0.5.9
[INFO] [stderr]    Compiling serde_derive v1.0.101
[INFO] [stderr]    Compiling futures-join-macro-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-select-macro-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-macro v0.3.1
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-util v0.3.1
[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/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" "d977ea4923050b2e0892d5821acc0f559de5e9d1d7997ae6e1c4a6df84c782a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d977ea4923050b2e0892d5821acc0f559de5e9d1d7997ae6e1c4a6df84c782a5", kill_on_drop: false }`
[INFO] [stdout] d977ea4923050b2e0892d5821acc0f559de5e9d1d7997ae6e1c4a6df84c782a5