[INFO] fetching crate agilulf 0.1.0...
[INFO] documenting agilulf-0.1.0 against 1.46.0 for beta-1.47-rustdoc-1
[INFO] extracting crate agilulf 0.1.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate agilulf 0.1.0 on toolchain 1.46.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate agilulf 0.1.0
[INFO] finished tweaking crates.io crate agilulf 0.1.0
[INFO] tweaked toml for crates.io crate agilulf 0.1.0 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.46.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 757e03dca642149d77426656f9e948559f090096623ade79480e2876d396e2f9
[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" "757e03dca642149d77426656f9e948559f090096623ade79480e2876d396e2f9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "757e03dca642149d77426656f9e948559f090096623ade79480e2876d396e2f9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "757e03dca642149d77426656f9e948559f090096623ade79480e2876d396e2f9", kill_on_drop: false }`
[INFO] [stdout] 757e03dca642149d77426656f9e948559f090096623ade79480e2876d396e2f9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "RUSTDOCFLAGS=--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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+1.46.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] be248c5b30b2df20ad9d28e18a9a8ab73e8beaaa235e9a3d902264290f8bddfa
[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" "be248c5b30b2df20ad9d28e18a9a8ab73e8beaaa235e9a3d902264290f8bddfa", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]     Checking futures-core-preview v0.3.0-alpha.17
[INFO] [stderr]    Compiling proc-macro-nested v0.1.6
[INFO] [stderr]    Compiling proc-macro-hack v0.5.18
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]     Checking futures-io-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking stable_deref_trait v1.2.0
[INFO] [stderr]     Checking quick-error v1.2.3
[INFO] [stderr]     Checking scopeguard v0.3.3
[INFO] [stderr]     Checking async-datagram v3.0.0
[INFO] [stderr]    Compiling nix v0.14.1
[INFO] [stderr]     Checking async-ready v3.0.0
[INFO] [stderr]     Checking unicode-width v0.1.8
[INFO] [stderr]     Checking regex-syntax v0.6.18
[INFO] [stderr]     Checking void v1.0.2
[INFO] [stderr]     Checking vec_map v0.8.2
[INFO] [stderr]     Checking termcolor v1.1.0
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]     Checking crossbeam-utils v0.6.6
[INFO] [stderr]     Checking thread_local v1.0.1
[INFO] [stderr]     Checking humantime v1.3.0
[INFO] [stderr]     Checking owning_ref v0.4.1
[INFO] [stderr]     Checking futures-sink-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking getrandom v0.1.14
[INFO] [stderr]     Checking net2 v0.2.34
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking memmap v0.7.0
[INFO] [stderr]    Compiling parking_lot_core v0.4.0
[INFO] [stderr]     Checking lock_api v0.1.5
[INFO] [stderr]     Checking futures-channel-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking crossbeam-queue v0.2.3
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking crossbeam v0.7.3
[INFO] [stderr]     Checking mio v0.6.22
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking aho-corasick v0.7.13
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking mio-uds v0.6.8
[INFO] [stderr]     Checking parking_lot v0.7.1
[INFO] [stderr]     Checking regex v1.3.9
[INFO] [stderr]     Checking env_logger v0.6.2
[INFO] [stderr]    Compiling futures-select-macro-preview v0.3.0-alpha.17
[INFO] [stderr]     Checking futures-util-preview v0.3.0-alpha.17
[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.17/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] running `Command { std: "docker" "inspect" "be248c5b30b2df20ad9d28e18a9a8ab73e8beaaa235e9a3d902264290f8bddfa", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "be248c5b30b2df20ad9d28e18a9a8ab73e8beaaa235e9a3d902264290f8bddfa", kill_on_drop: false }`
[INFO] [stdout] be248c5b30b2df20ad9d28e18a9a8ab73e8beaaa235e9a3d902264290f8bddfa