[INFO] fetching crate fb_futures_ext 0.1.2...
[INFO] testing fb_futures_ext-0.1.2 against 1.59.0 for beta-1.60-1
[INFO] extracting crate fb_futures_ext 0.1.2 into /workspace/builds/worker-21/source
[INFO] validating manifest of crates.io crate fb_futures_ext 0.1.2 on toolchain 1.59.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate fb_futures_ext 0.1.2
[INFO] finished tweaking crates.io crate fb_futures_ext 0.1.2
[INFO] tweaked toml for crates.io crate fb_futures_ext 0.1.2 written to /workspace/builds/worker-21/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.59.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-21/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-21/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6cf873ebcb211ec69239ccfc558976da5d91926f264a4902420b23a47a01573f
[INFO] running `Command { std: "docker" "start" "-a" "6cf873ebcb211ec69239ccfc558976da5d91926f264a4902420b23a47a01573f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6cf873ebcb211ec69239ccfc558976da5d91926f264a4902420b23a47a01573f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6cf873ebcb211ec69239ccfc558976da5d91926f264a4902420b23a47a01573f", kill_on_drop: false }`
[INFO] [stdout] 6cf873ebcb211ec69239ccfc558976da5d91926f264a4902420b23a47a01573f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-21/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-21/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:0cd99ca24d8e8c98e67c542213511d985b8778b5bdcbb160e038429496686047" "/opt/rustwide/cargo-home/bin/cargo" "+1.59.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d2b573c5a8dd7cabc2ada337dd35f73ecfdfc6e113fb4d570a4bf1ec4949a4a1
[INFO] running `Command { std: "docker" "start" "-a" "d2b573c5a8dd7cabc2ada337dd35f73ecfdfc6e113fb4d570a4bf1ec4949a4a1", kill_on_drop: false }`
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling mio-uds v0.6.8
[INFO] [stderr]    Compiling tokio-threadpool v0.1.18
[INFO] [stderr]    Compiling tokio-io v0.1.13
[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 tokio-udp v0.1.6
[INFO] [stderr]    Compiling tokio-uds v0.2.7
[INFO] [stderr]    Compiling tokio-tcp v0.1.4
[INFO] [stderr]    Compiling tokio v0.1.22
[INFO] [stderr]    Compiling fb_futures_ext v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:11:1
[INFO] [stdout]    |
[INFO] [stdout] 11 | #![feature(never_type)]
[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 `fb_futures_ext` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "d2b573c5a8dd7cabc2ada337dd35f73ecfdfc6e113fb4d570a4bf1ec4949a4a1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d2b573c5a8dd7cabc2ada337dd35f73ecfdfc6e113fb4d570a4bf1ec4949a4a1", kill_on_drop: false }`
[INFO] [stdout] d2b573c5a8dd7cabc2ada337dd35f73ecfdfc6e113fb4d570a4bf1ec4949a4a1