[INFO] fetching crate letsgo 0.0.1...
[INFO] testing letsgo-0.0.1 against 1.75.0 for beta-1.76-1
[INFO] extracting crate letsgo 0.0.1 into /workspace/builds/worker-2-tc1/source
[INFO] validating manifest of crates.io crate letsgo 0.0.1 on toolchain 1.75.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate letsgo 0.0.1
[INFO] finished tweaking crates.io crate letsgo 0.0.1
[INFO] tweaked toml for crates.io crate letsgo 0.0.1 written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded futures-executor-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded runtime-native v0.3.0-alpha.6
[INFO] [stderr]   Downloaded async-datagram v3.0.0
[INFO] [stderr]   Downloaded async-ready v3.0.0
[INFO] [stderr]   Downloaded futures-join-macro-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded juliex v0.3.0-alpha.8
[INFO] [stderr]   Downloaded futures-select-macro-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded futures-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded futures-util-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded runtime-raw v0.3.0-alpha.5
[INFO] [stderr]   Downloaded futures-timer v0.3.0
[INFO] [stderr]   Downloaded futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]   Downloaded runtime-attributes v0.3.0-alpha.6
[INFO] [stderr]   Downloaded romio v0.3.0-alpha.10
[INFO] [stderr]   Downloaded runtime-tokio v0.3.0-alpha.6
[INFO] [stderr]   Downloaded runtime v0.3.0-alpha.7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.75.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b88f2908f165d3f66e90b5e49ed9eae91f1ca8bb4cb2b70ad74094771a24f3ee
[INFO] running `Command { std: "docker" "start" "-a" "b88f2908f165d3f66e90b5e49ed9eae91f1ca8bb4cb2b70ad74094771a24f3ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b88f2908f165d3f66e90b5e49ed9eae91f1ca8bb4cb2b70ad74094771a24f3ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b88f2908f165d3f66e90b5e49ed9eae91f1ca8bb4cb2b70ad74094771a24f3ee", kill_on_drop: false }`
[INFO] [stdout] b88f2908f165d3f66e90b5e49ed9eae91f1ca8bb4cb2b70ad74094771a24f3ee
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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" "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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.75.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 194855647d35c02f3a9f3df62f9867475cd889efdf08ebcf20980ecc410b1eca
[INFO] running `Command { std: "docker" "start" "-a" "194855647d35c02f3a9f3df62f9867475cd889efdf08ebcf20980ecc410b1eca", kill_on_drop: false }`
[INFO] [stderr]    Compiling futures v0.1.31
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling memchr v2.7.1
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling proc-macro-hack v0.5.20+deprecated
[INFO] [stderr]    Compiling smallvec v0.6.14
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling memoffset v0.5.6
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]    Compiling parking_lot_core v0.6.3
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling proc-macro-nested v0.1.7
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling tokio-io v0.1.13
[INFO] [stderr]    Compiling tokio-executor v0.1.10
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling autocfg v0.1.8
[INFO] [stderr]    Compiling proc-macro2 v1.0.75
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling crossbeam-queue v0.2.3
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling tokio-sync v0.1.8
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling tokio-codec v0.1.2
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling crossbeam-deque v0.7.4
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling tokio-reactor v0.1.12
[INFO] [stderr]    Compiling miniz_oxide v0.7.1
[INFO] [stderr]    Compiling tokio-threadpool v0.1.18
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling quote v1.0.35
[INFO] [stderr]    Compiling tokio-timer v0.2.13
[INFO] [stderr]    Compiling tokio-udp v0.1.6
[INFO] [stderr]    Compiling tokio-tcp v0.1.4
[INFO] [stderr]    Compiling crossbeam-channel v0.4.4
[INFO] [stderr]    Compiling object v0.32.2
[INFO] [stderr]    Compiling tokio-fs v0.1.7
[INFO] [stderr]    Compiling tokio-uds v0.2.7
[INFO] [stderr]    Compiling crossbeam v0.7.3
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling tokio-current-thread v0.1.7
[INFO] [stderr]    Compiling crossbeam-utils v0.6.6
[INFO] [stderr]    Compiling async-ready v3.0.0
[INFO] [stderr]    Compiling async-datagram v3.0.0
[INFO] [stderr]    Compiling tokio v0.1.22
[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 enum-as-inner v0.2.1
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.18
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/index.crates.io-6f17d22bba15001f/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]   |                                      ^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `async_await` has been stable since `1.39.0` and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling backtrace v0.3.69
[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` (lib) due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "194855647d35c02f3a9f3df62f9867475cd889efdf08ebcf20980ecc410b1eca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "194855647d35c02f3a9f3df62f9867475cd889efdf08ebcf20980ecc410b1eca", kill_on_drop: false }`
[INFO] [stdout] 194855647d35c02f3a9f3df62f9867475cd889efdf08ebcf20980ecc410b1eca
