[INFO] cloning repository https://github.com/quadruple-output/game-2048-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/quadruple-output/game-2048-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fquadruple-output%2Fgame-2048-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fquadruple-output%2Fgame-2048-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 95e357d42eb54e5f4bcce428ced5b158f2734ff6
[INFO] testing quadruple-output/game-2048-rust against beta-2021-01-01 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fquadruple-output%2Fgame-2048-rust" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/quadruple-output/game-2048-rust on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/quadruple-output/game-2048-rust
[INFO] finished tweaking git repo https://github.com/quadruple-output/game-2048-rust
[INFO] tweaked toml for git repo https://github.com/quadruple-output/game-2048-rust written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate git repo https://github.com/quadruple-output/game-2048-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0fd3c51e49a61d4400ade147e2c69379db73774df096422f84c0a5a7cc022b5c
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "0fd3c51e49a61d4400ade147e2c69379db73774df096422f84c0a5a7cc022b5c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0fd3c51e49a61d4400ade147e2c69379db73774df096422f84c0a5a7cc022b5c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0fd3c51e49a61d4400ade147e2c69379db73774df096422f84c0a5a7cc022b5c", kill_on_drop: false }`
[INFO] [stdout] 0fd3c51e49a61d4400ade147e2c69379db73774df096422f84c0a5a7cc022b5c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "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] 3c1250fe05bfa1d09ff3089d27ec5b2c1d1be35af37f1272a2761d16050a51f2
[INFO] running `Command { std: "docker" "start" "-a" "3c1250fe05bfa1d09ff3089d27ec5b2c1d1be35af37f1272a2761d16050a51f2", kill_on_drop: false }`
[INFO] [stderr]    Compiling pkg-config v0.3.16
[INFO] [stderr]    Compiling cc v1.0.45
[INFO] [stderr]    Compiling regex-syntax v0.6.17
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr]    Compiling atty v0.2.11
[INFO] [stderr]    Compiling clicolors-control v1.0.1
[INFO] [stderr]    Compiling termios v0.3.1
[INFO] [stderr]    Compiling thread_local v0.3.4
[INFO] [stderr]    Compiling rand v0.4.6
[INFO] [stderr]    Compiling crossbeam-queue v0.2.1
[INFO] [stderr]    Compiling chrono v0.4.10
[INFO] [stderr]    Compiling crossbeam v0.7.3
[INFO] [stderr]    Compiling clap v2.33.0
[INFO] [stderr]    Compiling ncurses v5.99.0
[INFO] [stderr]    Compiling stderrlog v0.4.3
[INFO] [stderr]    Compiling regex v1.3.5
[INFO] [stderr]    Compiling console v0.10.0
[INFO] [stderr]    Compiling game2048 v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(non_ascii_idents)] // used in animator.rs
[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 `game2048`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "3c1250fe05bfa1d09ff3089d27ec5b2c1d1be35af37f1272a2761d16050a51f2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3c1250fe05bfa1d09ff3089d27ec5b2c1d1be35af37f1272a2761d16050a51f2", kill_on_drop: false }`
[INFO] [stdout] 3c1250fe05bfa1d09ff3089d27ec5b2c1d1be35af37f1272a2761d16050a51f2