[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 beta-2021-01-01 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-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/codebam/chatserver-rust on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "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-12/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" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded futures-timer v0.4.0
[INFO] [stderr]   Downloaded futures-select-macro-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded futures-join-macro-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded async-std v0.99.6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e30b091338a446b6fa40a89749aeed607c2b92f965d40164820bf967345fb3b2
[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" "e30b091338a446b6fa40a89749aeed607c2b92f965d40164820bf967345fb3b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e30b091338a446b6fa40a89749aeed607c2b92f965d40164820bf967345fb3b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e30b091338a446b6fa40a89749aeed607c2b92f965d40164820bf967345fb3b2", kill_on_drop: false }`
[INFO] [stdout] e30b091338a446b6fa40a89749aeed607c2b92f965d40164820bf967345fb3b2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5b6f05394977c2238ddfbc1ec1be5cdd591471902c3c7d11fa380c4db87da593
[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" "5b6f05394977c2238ddfbc1ec1be5cdd591471902c3c7d11fa380c4db87da593", 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 proc-macro-nested v0.1.3
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling serde v1.0.101
[INFO] [stderr]    Compiling futures-core v0.3.1
[INFO] [stderr]    Compiling crossbeam-channel v0.3.9
[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 block-buffer v0.7.3
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.2
[INFO] [stderr]    Compiling sha2 v0.8.0
[INFO] [stderr]    Compiling futures-channel v0.3.1
[INFO] [stderr]    Compiling crossbeam-deque v0.7.1
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling async-macros v1.0.0
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling mio v0.6.19
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling rand v0.7.2
[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-select-macro-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-join-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 beta 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" "5b6f05394977c2238ddfbc1ec1be5cdd591471902c3c7d11fa380c4db87da593", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5b6f05394977c2238ddfbc1ec1be5cdd591471902c3c7d11fa380c4db87da593", kill_on_drop: false }`
[INFO] [stdout] 5b6f05394977c2238ddfbc1ec1be5cdd591471902c3c7d11fa380c4db87da593