[INFO] cloning repository https://github.com/rrichardson/tokio-cookbook
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/rrichardson/tokio-cookbook" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frrichardson%2Ftokio-cookbook", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frrichardson%2Ftokio-cookbook'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 989e8f4bef9e4d670237ffeab578afee160d42ae
[INFO] testing rrichardson/tokio-cookbook against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frrichardson%2Ftokio-cookbook" "/workspace/builds/worker-11/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/rrichardson/tokio-cookbook on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/rrichardson/tokio-cookbook
[INFO] finished tweaking git repo https://github.com/rrichardson/tokio-cookbook
[INFO] tweaked toml for git repo https://github.com/rrichardson/tokio-cookbook written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate git repo https://github.com/rrichardson/tokio-cookbook already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded rand v0.7.1
[INFO] [stderr]   Downloaded tokio-codec v0.2.0-alpha.4
[INFO] [stderr]   Downloaded tokio-fs v0.2.0-alpha.4
[INFO] [stderr]   Downloaded tokio-net v0.2.0-alpha.4
[INFO] [stderr]   Downloaded tokio-timer v0.3.0-alpha.4
[INFO] [stderr]   Downloaded tokio-executor v0.2.0-alpha.4
[INFO] [stderr]   Downloaded tracing-attributes v0.1.3
[INFO] [stderr]   Downloaded tokio v0.2.0-alpha.4
[INFO] [stderr]   Downloaded tokio-macros v0.2.0-alpha.4
[INFO] [stderr]   Downloaded tokio-sync v0.2.0-alpha.4
[INFO] [stderr]   Downloaded tokio-io v0.2.0-alpha.4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 3f31220d4d7f646036e97b58010996a0518636cf5fae6bd6c64bb229c77ba08a
[INFO] running `Command { std: "docker" "start" "-a" "3f31220d4d7f646036e97b58010996a0518636cf5fae6bd6c64bb229c77ba08a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3f31220d4d7f646036e97b58010996a0518636cf5fae6bd6c64bb229c77ba08a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3f31220d4d7f646036e97b58010996a0518636cf5fae6bd6c64bb229c77ba08a", kill_on_drop: false }`
[INFO] [stdout] 3f31220d4d7f646036e97b58010996a0518636cf5fae6bd6c64bb229c77ba08a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 565bd85435ccd7bff58dbb4ccded5510543ac1f0fbbf7391e2aa0789610c47ef
[INFO] running `Command { std: "docker" "start" "-a" "565bd85435ccd7bff58dbb4ccded5510543ac1f0fbbf7391e2aa0789610c47ef", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.62
[INFO] [stderr]    Compiling proc-macro2 v1.0.3
[INFO] [stderr]    Compiling syn v1.0.5
[INFO] [stderr]    Compiling getrandom v0.1.12
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling ppv-lite86 v0.2.5
[INFO] [stderr]    Compiling pin-utils v0.1.0-alpha.4
[INFO] [stderr]    Compiling proc-macro-nested v0.1.3
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling arrayvec v0.4.11
[INFO] [stderr]    Compiling lock_api v0.3.1
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling crossbeam-utils v0.6.6
[INFO] [stderr]    Compiling tracing-core v0.1.6
[INFO] [stderr]    Compiling memoffset v0.5.1
[INFO] [stderr]    Compiling parking_lot_core v0.6.2
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling crossbeam-queue v0.1.2
[INFO] [stderr]    Compiling crossbeam-channel v0.3.9
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.18
[INFO] [stderr]    Compiling c2-chacha v0.2.2
[INFO] [stderr]    Compiling crossbeam-epoch v0.7.2
[INFO] [stderr]    Compiling quote v1.0.2
[INFO] [stderr]    Compiling iovec v0.1.2
[INFO] [stderr]    Compiling num_cpus v1.10.1
[INFO] [stderr]    Compiling net2 v0.2.33
[INFO] [stderr]    Compiling crossbeam-deque v0.7.1
[INFO] [stderr]    Compiling bytes v0.4.12
[INFO] [stderr]    Compiling rand_core v0.5.1
[INFO] [stderr]    Compiling mio v0.6.19
[INFO] [stderr]    Compiling rand_chacha v0.2.1
[INFO] [stderr]    Compiling tokio-io v0.2.0-alpha.4
[INFO] [stderr]    Compiling rand v0.7.1
[INFO] [stderr]    Compiling tokio-codec v0.2.0-alpha.4
[INFO] [stderr]    Compiling mio-uds v0.6.7
[INFO] [stderr]    Compiling proc-macro-hack v0.5.9
[INFO] [stderr]    Compiling tracing-attributes v0.1.3
[INFO] [stderr]    Compiling tokio-macros v0.2.0-alpha.4
[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 tracing v0.1.9
[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/github.com-1ecc6299db9ec823/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] [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` due to 2 previous errors
[INFO] running `Command { std: "docker" "inspect" "565bd85435ccd7bff58dbb4ccded5510543ac1f0fbbf7391e2aa0789610c47ef", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "565bd85435ccd7bff58dbb4ccded5510543ac1f0fbbf7391e2aa0789610c47ef", kill_on_drop: false }`
[INFO] [stdout] 565bd85435ccd7bff58dbb4ccded5510543ac1f0fbbf7391e2aa0789610c47ef