[INFO] fetching crate teleboard 0.1.0...
[INFO] testing teleboard-0.1.0 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate teleboard 0.1.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate teleboard 0.1.0 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 crates.io crate teleboard 0.1.0
[INFO] finished tweaking crates.io crate teleboard 0.1.0
[INFO] tweaked toml for crates.io crate teleboard 0.1.0 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate crates.io crate teleboard 0.1.0 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]  Downloading crates ...
[INFO] [stderr]   Downloaded once_cell v1.4.1
[INFO] [stderr]   Downloaded sha-1 v0.8.2
[INFO] [stderr]   Downloaded byte-tools v0.3.1
[INFO] [stderr]   Downloaded buf_redux v0.8.4
[INFO] [stderr]   Downloaded twoway v0.1.8
[INFO] [stderr]   Downloaded generic-array v0.12.3
[INFO] [stderr]   Downloaded futures v0.3.6
[INFO] [stderr]   Downloaded arc-swap v0.4.7
[INFO] [stderr]   Downloaded digest v0.9.0
[INFO] [stderr]   Downloaded digest v0.8.1
[INFO] [stderr]   Downloaded input_buffer v0.3.1
[INFO] [stderr]   Downloaded dtoa v0.4.6
[INFO] [stderr]   Downloaded block-buffer v0.7.3
[INFO] [stderr]   Downloaded opaque-debug v0.2.3
[INFO] [stderr]   Downloaded tinyvec v0.3.4
[INFO] [stderr]   Downloaded futures-core v0.3.6
[INFO] [stderr]   Downloaded futures-sink v0.3.6
[INFO] [stderr]   Downloaded headers-core v0.2.0
[INFO] [stderr]   Downloaded proc-macro-hack v0.5.18
[INFO] [stderr]   Downloaded futures-channel v0.3.6
[INFO] [stderr]   Downloaded h2 v0.2.6
[INFO] [stderr]   Downloaded futures-io v0.3.6
[INFO] [stderr]   Downloaded parking_lot_core v0.7.2
[INFO] [stderr]   Downloaded async-trait v0.1.41
[INFO] [stderr]   Downloaded instant v0.1.7
[INFO] [stderr]   Downloaded parking_lot v0.11.0
[INFO] [stderr]   Downloaded cassowary v0.3.0
[INFO] [stderr]   Downloaded signal-hook v0.1.16
[INFO] [stderr]   Downloaded lock_api v0.4.1
[INFO] [stderr]   Downloaded smallvec v1.4.2
[INFO] [stderr]   Downloaded parking_lot_core v0.8.0
[INFO] [stderr]   Downloaded anyhow v1.0.33
[INFO] [stderr]   Downloaded cloudabi v0.1.0
[INFO] [stderr]   Downloaded crossterm_winapi v0.6.1
[INFO] [stderr]   Downloaded futures-task v0.3.6
[INFO] [stderr]   Downloaded urlencoding v1.1.1
[INFO] [stderr]   Downloaded multipart v0.17.0
[INFO] [stderr]   Downloaded crossterm v0.17.7
[INFO] [stderr]   Downloaded ntapi v0.3.4
[INFO] [stderr]   Downloaded crossterm v0.18.0
[INFO] [stderr]   Downloaded mio v0.7.3
[INFO] [stderr]   Downloaded tui v0.12.0
[INFO] [stderr]   Downloaded libc v0.2.79
[INFO] [stderr]   Downloaded tokio v0.2.22
[INFO] [stderr]   Downloaded meio v0.11.0
[INFO] [stderr]   Downloaded syn v1.0.44
[INFO] [stderr]   Downloaded futures-util v0.3.6
[INFO] [stderr]   Downloaded meio-ws v0.1.0
[INFO] [stderr]   Downloaded unicode-segmentation v1.6.0
[INFO] [stderr]   Downloaded warp v0.2.5
[INFO] [stderr]   Downloaded headers v0.3.2
[INFO] [stderr]   Downloaded pin-project-lite v0.1.10
[INFO] [stderr]   Downloaded futures-executor v0.3.6
[INFO] [stderr]   Downloaded parking_lot v0.10.2
[INFO] [stderr]   Downloaded futures-macro v0.3.6
[INFO] [stderr]   Downloaded socket2 v0.3.15
[INFO] [stderr]   Downloaded signal-hook-registry v1.2.1
[INFO] [stderr]   Downloaded ppv-lite86 v0.2.9
[INFO] [stderr]   Downloaded base64 v0.12.3
[INFO] [stderr]   Downloaded block-buffer v0.9.0
[INFO] [stderr]   Downloaded tungstenite v0.11.1
[INFO] [stderr]   Downloaded serde_urlencoded v0.6.1
[INFO] [stderr]   Downloaded miow v0.3.5
[INFO] [stderr]   Downloaded generic-array v0.14.4
[INFO] [stderr]   Downloaded sha-1 v0.9.1
[INFO] [stderr]   Downloaded opaque-debug v0.3.0
[INFO] [stderr]   Downloaded unicode-normalization v0.1.13
[INFO] [stderr]   Downloaded url v2.1.1
[INFO] [stderr]   Downloaded hyper v0.13.8
[INFO] [stderr]   Downloaded scoped-tls v1.0.0
[INFO] [stderr]   Downloaded cpuid-bool v0.1.2
[INFO] [stderr]   Downloaded tokio-tungstenite v0.11.0
[INFO] [stderr]   Downloaded block-padding v0.1.5
[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" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 28c8af76771808211e1e8caf2df83572766a3e8b3c948d3f9bc771fe0be80cbf
[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" "28c8af76771808211e1e8caf2df83572766a3e8b3c948d3f9bc771fe0be80cbf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "28c8af76771808211e1e8caf2df83572766a3e8b3c948d3f9bc771fe0be80cbf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "28c8af76771808211e1e8caf2df83572766a3e8b3c948d3f9bc771fe0be80cbf", kill_on_drop: false }`
[INFO] [stdout] 28c8af76771808211e1e8caf2df83572766a3e8b3c948d3f9bc771fe0be80cbf
[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" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3663c480ca9b59afe0a8de968b1a3e1312142c3ba66a3ae15e76dca1fc9e9275
[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" "3663c480ca9b59afe0a8de968b1a3e1312142c3ba66a3ae15e76dca1fc9e9275", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling syn v1.0.44
[INFO] [stderr]    Compiling futures-sink v0.3.6
[INFO] [stderr]    Compiling urlencoding v1.1.1
[INFO] [stderr]    Compiling cassowary v0.3.0
[INFO] [stderr]    Compiling input_buffer v0.3.1
[INFO] [stderr]    Compiling instant v0.1.7
[INFO] [stderr]    Compiling lock_api v0.4.1
[INFO] [stderr]    Compiling headers-core v0.2.0
[INFO] [stderr]    Compiling signal-hook-registry v1.2.1
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling net2 v0.2.35
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling tracing v0.1.21
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling mio v0.7.3
[INFO] [stderr]    Compiling twoway v0.1.8
[INFO] [stderr]    Compiling parking_lot_core v0.7.2
[INFO] [stderr]    Compiling buf_redux v0.8.4
[INFO] [stderr]    Compiling socket2 v0.3.15
[INFO] [stderr]    Compiling url v2.1.1
[INFO] [stderr]    Compiling serde_json v1.0.59
[INFO] [stderr]    Compiling futures-channel v0.3.6
[INFO] [stderr]    Compiling parking_lot_core v0.8.0
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling signal-hook v0.1.16
[INFO] [stderr]    Compiling sha-1 v0.9.1
[INFO] [stderr]    Compiling mio v0.6.22
[INFO] [stderr]    Compiling parking_lot v0.10.2
[INFO] [stderr]    Compiling headers v0.3.2
[INFO] [stderr]    Compiling tempfile v3.1.0
[INFO] [stderr]    Compiling uuid v0.8.1
[INFO] [stderr]    Compiling parking_lot v0.11.0
[INFO] [stderr]    Compiling crossterm v0.17.7
[INFO] [stderr]    Compiling tungstenite v0.11.1
[INFO] [stderr]    Compiling serde_urlencoded v0.6.1
[INFO] [stderr]    Compiling crossterm v0.18.0
[INFO] [stderr]    Compiling multipart v0.17.0
[INFO] [stderr]    Compiling mio-uds v0.6.8
[INFO] [stderr]    Compiling tui v0.12.0
[INFO] [stderr]    Compiling pin-project-internal v0.4.27
[INFO] [stderr]    Compiling futures-macro v0.3.6
[INFO] [stderr]    Compiling tokio-macros v0.2.5
[INFO] [stderr]    Compiling derive_more v0.99.11
[INFO] [stderr]    Compiling async-trait v0.1.41
[INFO] [stderr]    Compiling tokio v0.2.22
[INFO] [stderr]    Compiling pin-project v0.4.27
[INFO] [stderr]    Compiling futures-util v0.3.6
[INFO] [stderr]    Compiling tracing-futures v0.2.4
[INFO] [stderr]    Compiling tokio-util v0.3.1
[INFO] [stderr]    Compiling futures-executor v0.3.6
[INFO] [stderr]    Compiling tokio-tungstenite v0.11.0
[INFO] [stderr]    Compiling h2 v0.2.6
[INFO] [stderr]    Compiling futures v0.3.6
[INFO] [stderr]    Compiling meio v0.11.0
[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/meio-0.11.0/src/lib.rs:13:1
[INFO] [stdout]    |
[INFO] [stdout] 13 | #![feature(generators)]
[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 `meio`
[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" "3663c480ca9b59afe0a8de968b1a3e1312142c3ba66a3ae15e76dca1fc9e9275", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3663c480ca9b59afe0a8de968b1a3e1312142c3ba66a3ae15e76dca1fc9e9275", kill_on_drop: false }`
[INFO] [stdout] 3663c480ca9b59afe0a8de968b1a3e1312142c3ba66a3ae15e76dca1fc9e9275