[INFO] fetching crate cobweb 0.2.2...
[INFO] testing cobweb-0.2.2 against 1.49.0 for beta-1.50-1
[INFO] extracting crate cobweb 0.2.2 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate cobweb 0.2.2 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 cobweb 0.2.2
[INFO] finished tweaking crates.io crate cobweb 0.2.2
[INFO] tweaked toml for crates.io crate cobweb 0.2.2 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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] 78a812cb863c23b3b6935d94948a2bcf16ae0efc126e52283b55a6aa594190cc
[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" "78a812cb863c23b3b6935d94948a2bcf16ae0efc126e52283b55a6aa594190cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "78a812cb863c23b3b6935d94948a2bcf16ae0efc126e52283b55a6aa594190cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "78a812cb863c23b3b6935d94948a2bcf16ae0efc126e52283b55a6aa594190cc", kill_on_drop: false }`
[INFO] [stdout] 78a812cb863c23b3b6935d94948a2bcf16ae0efc126e52283b55a6aa594190cc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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] 4d21f072436626170c6c96715442fc4a584a30ca422de4f19f9afa7deabbcf0f
[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" "4d21f072436626170c6c96715442fc4a584a30ca422de4f19f9afa7deabbcf0f", kill_on_drop: false }`
[INFO] [stderr] warning: only one of `license` or `license-file` is necessary
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling subtle v1.0.0
[INFO] [stderr]    Compiling scoped-tls v0.1.2
[INFO] [stderr]    Compiling zeroize v0.5.2
[INFO] [stderr]    Compiling tun-tap v0.1.2
[INFO] [stderr]    Compiling tun-tap-mac v0.1.2
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling generic-array v0.12.3
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling crypto-mac v0.5.2
[INFO] [stderr]    Compiling mio-uds v0.6.8
[INFO] [stderr]    Compiling rand v0.5.6
[INFO] [stderr]    Compiling blake2 v0.7.1
[INFO] [stderr]    Compiling block-cipher-trait v0.6.2
[INFO] [stderr]    Compiling dbl v0.2.1
[INFO] [stderr]    Compiling crypto-mac v0.7.0
[INFO] [stderr]    Compiling stream-cipher v0.3.2
[INFO] [stderr]    Compiling aes-soft v0.3.3
[INFO] [stderr]    Compiling ctr v0.3.2
[INFO] [stderr]    Compiling tokio-io v0.1.13
[INFO] [stderr]    Compiling pmac v0.2.0
[INFO] [stderr]    Compiling cmac v0.2.0
[INFO] [stderr]    Compiling aes v0.3.2
[INFO] [stderr]    Compiling miscreant v0.4.2
[INFO] [stderr]    Compiling tokio-reactor v0.1.12
[INFO] [stderr]    Compiling tokio-codec v0.1.2
[INFO] [stderr]    Compiling tokio-fs v0.1.7
[INFO] [stderr]    Compiling pbkdf2 v0.2.3
[INFO] [stderr]    Compiling keybob v0.3.1
[INFO] [stderr]    Compiling tokio-uds v0.2.7
[INFO] [stderr]    Compiling tokio-tcp v0.1.4
[INFO] [stderr]    Compiling tokio-udp v0.1.6
[INFO] [stderr]    Compiling tokio v0.1.22
[INFO] [stderr]    Compiling tokio-core v0.1.18
[INFO] [stderr]    Compiling cobweb v0.2.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(trivial_bounds)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(unboxed_closures)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(fn_traits)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `cobweb`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "4d21f072436626170c6c96715442fc4a584a30ca422de4f19f9afa7deabbcf0f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4d21f072436626170c6c96715442fc4a584a30ca422de4f19f9afa7deabbcf0f", kill_on_drop: false }`
[INFO] [stdout] 4d21f072436626170c6c96715442fc4a584a30ca422de4f19f9afa7deabbcf0f