[INFO] fetching crate udp_server 0.4.1...
[INFO] testing udp_server-0.4.1 against 1.55.0 for beta-1.56-1
[INFO] extracting crate udp_server 0.4.1 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate udp_server 0.4.1 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 udp_server 0.4.1
[INFO] finished tweaking crates.io crate udp_server 0.4.1
[INFO] tweaked toml for crates.io crate udp_server 0.4.1 written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] 7c4b3a7edb52026af1fd16370f612825ce573c820bf38804428d40423bc00f72
[INFO] running `Command { std: "docker" "start" "-a" "7c4b3a7edb52026af1fd16370f612825ce573c820bf38804428d40423bc00f72", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7c4b3a7edb52026af1fd16370f612825ce573c820bf38804428d40423bc00f72", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7c4b3a7edb52026af1fd16370f612825ce573c820bf38804428d40423bc00f72", kill_on_drop: false }`
[INFO] [stdout] 7c4b3a7edb52026af1fd16370f612825ce573c820bf38804428d40423bc00f72
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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] c881a75e836d220c171b658b733f1984fb7e7ff67e400c27ac45ebe45f8d0fd3
[INFO] running `Command { std: "docker" "start" "-a" "c881a75e836d220c171b658b733f1984fb7e7ff67e400c27ac45ebe45f8d0fd3", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling bytes v1.1.0
[INFO] [stderr]    Compiling tokio v1.11.0
[INFO] [stderr]    Compiling parking_lot_core v0.8.5
[INFO] [stderr]    Compiling signal-hook-registry v1.4.0
[INFO] [stderr]    Compiling mio v0.7.13
[INFO] [stderr]    Compiling net2 v0.2.37
[INFO] [stderr]    Compiling parking_lot v0.11.2
[INFO] [stderr]    Compiling futures-macro v0.3.17
[INFO] [stderr]    Compiling tokio-macros v1.3.0
[INFO] [stderr]    Compiling futures-util v0.3.17
[INFO] [stderr]    Compiling futures-executor v0.3.17
[INFO] [stderr]    Compiling futures v0.3.17
[INFO] [stderr]    Compiling udp_server v0.4.1 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 12.20s
[INFO] running `Command { std: "docker" "inspect" "c881a75e836d220c171b658b733f1984fb7e7ff67e400c27ac45ebe45f8d0fd3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c881a75e836d220c171b658b733f1984fb7e7ff67e400c27ac45ebe45f8d0fd3", kill_on_drop: false }`
[INFO] [stdout] c881a75e836d220c171b658b733f1984fb7e7ff67e400c27ac45ebe45f8d0fd3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4701ea81edd3b9f76c7a875ae8db8f653d9f27bf04f8715f3a4693b807f5145f
[INFO] running `Command { std: "docker" "start" "-a" "4701ea81edd3b9f76c7a875ae8db8f653d9f27bf04f8715f3a4693b807f5145f", kill_on_drop: false }`
[INFO] [stderr]    Compiling udp_server v0.4.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> tests/udp.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(async_closure)]
[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 `udp_server` 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" "4701ea81edd3b9f76c7a875ae8db8f653d9f27bf04f8715f3a4693b807f5145f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4701ea81edd3b9f76c7a875ae8db8f653d9f27bf04f8715f3a4693b807f5145f", kill_on_drop: false }`
[INFO] [stdout] 4701ea81edd3b9f76c7a875ae8db8f653d9f27bf04f8715f3a4693b807f5145f