[INFO] cloning repository https://github.com/tuzz/audio_mixer
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tuzz/audio_mixer" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftuzz%2Faudio_mixer", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftuzz%2Faudio_mixer'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 5fef2d570552dcc517739a7cd8fb2f6fdda2026b
[INFO] testing tuzz/audio_mixer against 1.59.0 for beta-1.60-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftuzz%2Faudio_mixer" "/workspace/builds/worker-26/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-26/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/tuzz/audio_mixer 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 git repo https://github.com/tuzz/audio_mixer
[INFO] finished tweaking git repo https://github.com/tuzz/audio_mixer
[INFO] tweaked toml for git repo https://github.com/tuzz/audio_mixer written to /workspace/builds/worker-26/source/Cargo.toml
[INFO] crate git repo https://github.com/tuzz/audio_mixer already has a lockfile, it will not be regenerated
[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-26/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/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] aaf8760249cd03612a41cb5ea6e817ef697faa4660afcdb52a2a9065238bdc1c
[INFO] running `Command { std: "docker" "start" "-a" "aaf8760249cd03612a41cb5ea6e817ef697faa4660afcdb52a2a9065238bdc1c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "aaf8760249cd03612a41cb5ea6e817ef697faa4660afcdb52a2a9065238bdc1c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aaf8760249cd03612a41cb5ea6e817ef697faa4660afcdb52a2a9065238bdc1c", kill_on_drop: false }`
[INFO] [stdout] aaf8760249cd03612a41cb5ea6e817ef697faa4660afcdb52a2a9065238bdc1c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-26/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] 2e3d85e774a5b92f6cffce827d439a092cf2cede7e23e6f2b7f86e8f6da76dcf
[INFO] running `Command { std: "docker" "start" "-a" "2e3d85e774a5b92f6cffce827d439a092cf2cede7e23e6f2b7f86e8f6da76dcf", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.101
[INFO] [stderr]    Compiling proc-macro2 v1.0.29
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling cpal v0.13.4
[INFO] [stderr]    Compiling atomic_float v0.1.0
[INFO] [stderr]    Compiling instant v0.1.10
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling alsa-sys v0.3.1
[INFO] [stderr]    Compiling nix v0.20.1
[INFO] [stderr]    Compiling parking_lot_core v0.8.5
[INFO] [stderr]    Compiling parking_lot v0.11.2
[INFO] [stderr]    Compiling thiserror-impl v1.0.29
[INFO] [stderr]    Compiling alsa v0.5.0
[INFO] [stderr]    Compiling thiserror v1.0.29
[INFO] [stderr]    Compiling audio_mixer v0.1.0 (/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(drain_filter)]
[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(bool_to_option)]
[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(once_cell)]
[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:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(trait_alias)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 4 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 `audio_mixer` due to 5 previous errors
[INFO] running `Command { std: "docker" "inspect" "2e3d85e774a5b92f6cffce827d439a092cf2cede7e23e6f2b7f86e8f6da76dcf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2e3d85e774a5b92f6cffce827d439a092cf2cede7e23e6f2b7f86e8f6da76dcf", kill_on_drop: false }`
[INFO] [stdout] 2e3d85e774a5b92f6cffce827d439a092cf2cede7e23e6f2b7f86e8f6da76dcf