[INFO] fetching crate kcpserver 0.3.1...
[INFO] testing kcpserver-0.3.1 against 1.60.0 for beta-1.61-1
[INFO] extracting crate kcpserver 0.3.1 into /workspace/builds/worker-51/source
[INFO] validating manifest of crates.io crate kcpserver 0.3.1 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 crates.io crate kcpserver 0.3.1
[INFO] finished tweaking crates.io crate kcpserver 0.3.1
[INFO] tweaked toml for crates.io crate kcpserver 0.3.1 written to /workspace/builds/worker-51/source/Cargo.toml
[INFO] crate crates.io crate kcpserver 0.3.1 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]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded const-random-macro v0.1.8
[INFO] [stderr]   Downloaded ahash v0.4.5
[INFO] [stderr]   Downloaded const-random v0.1.8
[INFO] [stderr]   Downloaded tokio v1.1.1
[INFO] [stderr]   Downloaded xbinary v0.1.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0c1d648e53da47bad7ad8f08922076655f0e423adca838e768374d1b452e20d8
[INFO] running `Command { std: "docker" "start" "-a" "0c1d648e53da47bad7ad8f08922076655f0e423adca838e768374d1b452e20d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0c1d648e53da47bad7ad8f08922076655f0e423adca838e768374d1b452e20d8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0c1d648e53da47bad7ad8f08922076655f0e423adca838e768374d1b452e20d8", kill_on_drop: false }`
[INFO] [stdout] 0c1d648e53da47bad7ad8f08922076655f0e423adca838e768374d1b452e20d8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a922cd0ec59e325471148276c2083cf8248132e6b4b1528f637b09c18a60d6e3
[INFO] running `Command { std: "docker" "start" "-a" "a922cd0ec59e325471148276c2083cf8248132e6b4b1528f637b09c18a60d6e3", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.77
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling proc-macro2 v1.0.21
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.40
[INFO] [stderr]    Compiling getrandom v0.1.15
[INFO] [stderr]    Compiling log v0.4.11
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stderr]    Compiling scopeguard v1.1.0
[INFO] [stderr]    Compiling smallvec v1.6.1
[INFO] [stderr]    Compiling proc-macro-hack v0.5.18
[INFO] [stderr]    Compiling arc-swap v0.4.7
[INFO] [stderr]    Compiling bytes v1.0.1
[INFO] [stderr]    Compiling pin-project-lite v0.2.4
[INFO] [stderr]    Compiling once_cell v1.5.2
[INFO] [stderr]    Compiling bytes v0.5.6
[INFO] [stderr]    Compiling event-listener v2.5.1
[INFO] [stderr]    Compiling lock_api v0.4.2
[INFO] [stderr]    Compiling instant v0.1.9
[INFO] [stderr]    Compiling async-mutex v1.4.0
[INFO] [stderr]    Compiling num-traits v0.2.12
[INFO] [stderr]    Compiling num-integer v0.1.43
[INFO] [stderr]    Compiling tokio v1.1.1
[INFO] [stderr]    Compiling xbinary v0.1.2
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling parking_lot_core v0.8.2
[INFO] [stderr]    Compiling num_cpus v1.13.0
[INFO] [stderr]    Compiling mio v0.7.7
[INFO] [stderr]    Compiling signal-hook-registry v1.2.1
[INFO] [stderr]    Compiling time v0.1.44
[INFO] [stderr]    Compiling net2 v0.2.35
[INFO] [stderr]    Compiling parking_lot v0.11.1
[INFO] [stderr]    Compiling const-random-macro v0.1.8
[INFO] [stderr]    Compiling const-random v0.1.8
[INFO] [stderr]    Compiling ahash v0.4.5
[INFO] [stderr]    Compiling chrono v0.4.15
[INFO] [stderr]    Compiling tokio-macros v1.0.0
[INFO] [stderr]    Compiling async-trait v0.1.40
[INFO] [stderr]    Compiling kcpserver v0.3.1 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 16.01s
[INFO] running `Command { std: "docker" "inspect" "a922cd0ec59e325471148276c2083cf8248132e6b4b1528f637b09c18a60d6e3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a922cd0ec59e325471148276c2083cf8248132e6b4b1528f637b09c18a60d6e3", kill_on_drop: false }`
[INFO] [stdout] a922cd0ec59e325471148276c2083cf8248132e6b4b1528f637b09c18a60d6e3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-51/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a37d89f75b7ef070aaaa26a6e13456e1326cd8aa66be61ec2a4d94eb0190fbb3
[INFO] running `Command { std: "docker" "start" "-a" "a37d89f75b7ef070aaaa26a6e13456e1326cd8aa66be61ec2a4d94eb0190fbb3", kill_on_drop: false }`
[INFO] [stderr]    Compiling kcpserver v0.3.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> examples/kcpecho/main.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 `kcpserver` 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" "a37d89f75b7ef070aaaa26a6e13456e1326cd8aa66be61ec2a4d94eb0190fbb3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a37d89f75b7ef070aaaa26a6e13456e1326cd8aa66be61ec2a4d94eb0190fbb3", kill_on_drop: false }`
[INFO] [stdout] a37d89f75b7ef070aaaa26a6e13456e1326cd8aa66be61ec2a4d94eb0190fbb3