[INFO] fetching crate o5m-stream 2.0.0...
[INFO] testing o5m-stream-2.0.0 against 1.55.0 for beta-1.56-1
[INFO] extracting crate o5m-stream 2.0.0 into /workspace/builds/worker-64/source
[INFO] validating manifest of crates.io crate o5m-stream 2.0.0 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate o5m-stream 2.0.0
[INFO] finished tweaking crates.io crate o5m-stream 2.0.0
[INFO] tweaked toml for crates.io crate o5m-stream 2.0.0 written to /workspace/builds/worker-64/source/Cargo.toml
[INFO] crate crates.io crate o5m-stream 2.0.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded futures-executor v0.3.13
[INFO] [stderr]   Downloaded signal-hook v0.3.8
[INFO] [stderr]   Downloaded futures v0.3.13
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-64/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-64/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8800f38fab51a1f9ac72b68e265594eddabf1783240cf1a5f8bc47d4404f232f
[INFO] running `Command { std: "docker" "start" "-a" "8800f38fab51a1f9ac72b68e265594eddabf1783240cf1a5f8bc47d4404f232f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8800f38fab51a1f9ac72b68e265594eddabf1783240cf1a5f8bc47d4404f232f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8800f38fab51a1f9ac72b68e265594eddabf1783240cf1a5f8bc47d4404f232f", kill_on_drop: false }`
[INFO] [stdout] 8800f38fab51a1f9ac72b68e265594eddabf1783240cf1a5f8bc47d4404f232f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-64/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-64/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] bd6ff3da3e54b4b1ffd44161670980a978cd77457499f3724d941a1e6adc1d4e
[INFO] running `Command { std: "docker" "start" "-a" "bd6ff3da3e54b4b1ffd44161670980a978cd77457499f3724d941a1e6adc1d4e", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.26
[INFO] [stderr]    Compiling syn v1.0.69
[INFO] [stderr]    Compiling libc v0.2.93
[INFO] [stderr]    Compiling futures-core v0.3.13
[INFO] [stderr]    Compiling pin-project-lite v0.2.6
[INFO] [stderr]    Compiling futures-io v0.3.13
[INFO] [stderr]    Compiling value-bag v1.0.0-alpha.6
[INFO] [stderr]    Compiling fastrand v1.4.0
[INFO] [stderr]    Compiling once_cell v1.7.2
[INFO] [stderr]    Compiling vec-arena v1.1.0
[INFO] [stderr]    Compiling signal-hook v0.3.8
[INFO] [stderr]    Compiling futures-sink v0.3.13
[INFO] [stderr]    Compiling futures-task v0.3.13
[INFO] [stderr]    Compiling crossbeam-utils v0.8.3
[INFO] [stderr]    Compiling async-lock v2.3.0
[INFO] [stderr]    Compiling futures-channel v0.3.13
[INFO] [stderr]    Compiling async-channel v1.6.1
[INFO] [stderr]    Compiling futures-lite v1.11.3
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling async-executor v1.4.0
[INFO] [stderr]    Compiling blocking v1.0.2
[INFO] [stderr]    Compiling socket2 v0.4.0
[INFO] [stderr]    Compiling signal-hook-registry v1.3.0
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling nb-connect v1.1.0
[INFO] [stderr]    Compiling ctor v0.1.20
[INFO] [stderr]    Compiling futures-macro v0.3.13
[INFO] [stderr]    Compiling thiserror-impl v1.0.24
[INFO] [stderr]    Compiling async-attributes v1.1.2
[INFO] [stderr]    Compiling futures-util v0.3.13
[INFO] [stderr]    Compiling thiserror v1.0.24
[INFO] [stderr]    Compiling log v0.4.14
[INFO] [stderr]    Compiling polling v2.0.3
[INFO] [stderr]    Compiling kv-log-macro v1.0.7
[INFO] [stderr]    Compiling async-io v1.3.1
[INFO] [stderr]    Compiling async-global-executor v2.0.2
[INFO] [stderr]    Compiling async-process v1.0.2
[INFO] [stderr]    Compiling async-std v1.9.0
[INFO] [stderr]    Compiling futures-executor v0.3.13
[INFO] [stderr]    Compiling futures v0.3.13
[INFO] [stderr]    Compiling o5m-stream v2.0.0 (/opt/rustwide/workdir)
[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(async_closure,backtrace)]
[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 `o5m-stream` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "bd6ff3da3e54b4b1ffd44161670980a978cd77457499f3724d941a1e6adc1d4e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bd6ff3da3e54b4b1ffd44161670980a978cd77457499f3724d941a1e6adc1d4e", kill_on_drop: false }`
[INFO] [stdout] bd6ff3da3e54b4b1ffd44161670980a978cd77457499f3724d941a1e6adc1d4e