[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] documenting quadruple-output/game-2048-rust against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fquadruple-output%2Fgame-2048-rust" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/quadruple-output/game-2048-rust on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "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-4/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-2020-08-29" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded regex v1.3.5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 43bde643c700741ae75763f2f20849c86352a63908c021e524bd240b9b086745
[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" "43bde643c700741ae75763f2f20849c86352a63908c021e524bd240b9b086745", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "43bde643c700741ae75763f2f20849c86352a63908c021e524bd240b9b086745", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "43bde643c700741ae75763f2f20849c86352a63908c021e524bd240b9b086745", kill_on_drop: false }`
[INFO] [stdout] 43bde643c700741ae75763f2f20849c86352a63908c021e524bd240b9b086745
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "RUSTDOCFLAGS=--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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c54b0a6c4caf896572b1a5f614dab4ec9cbfe6702a3ac0369722d8e9d6ff0a67
[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" "c54b0a6c4caf896572b1a5f614dab4ec9cbfe6702a3ac0369722d8e9d6ff0a67", kill_on_drop: false }`
[INFO] [stderr]    Compiling pkg-config v0.3.16
[INFO] [stderr]    Compiling cc v1.0.45
[INFO] [stderr]     Checking regex-syntax v0.6.17
[INFO] [stderr]     Checking atty v0.2.11
[INFO] [stderr]     Checking clicolors-control v1.0.1
[INFO] [stderr]     Checking termios v0.3.1
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking thread_local v0.3.4
[INFO] [stderr]     Checking chrono v0.4.10
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking stderrlog v0.4.3
[INFO] [stderr]    Compiling ncurses v5.99.0
[INFO] [stderr]     Checking regex v1.3.5
[INFO] [stderr]     Checking console v0.10.0
[INFO] [stderr]  Documenting 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: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 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 document `game2048`.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name game2048 src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --extern clap=/opt/rustwide/target/debug/deps/libclap-4840fda3e83a08ea.rmeta --extern console=/opt/rustwide/target/debug/deps/libconsole-015189a4c32257fd.rmeta --extern crossbeam=/opt/rustwide/target/debug/deps/libcrossbeam-1d11686e5609488c.rmeta --extern log=/opt/rustwide/target/debug/deps/liblog-69d9a7f018cb28c7.rmeta --extern ncurses=/opt/rustwide/target/debug/deps/libncurses-cb4e0f29558ffb6f.rmeta --extern rand=/opt/rustwide/target/debug/deps/librand-d5f5640e9463ed31.rmeta --extern stderrlog=/opt/rustwide/target/debug/deps/libstderrlog-cd97b74d4b5e3660.rmeta --cap-lints=warn --crate-version 0.1.1` (exit code: 1)
[INFO] running `Command { std: "docker" "inspect" "c54b0a6c4caf896572b1a5f614dab4ec9cbfe6702a3ac0369722d8e9d6ff0a67", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c54b0a6c4caf896572b1a5f614dab4ec9cbfe6702a3ac0369722d8e9d6ff0a67", kill_on_drop: false }`
[INFO] [stdout] c54b0a6c4caf896572b1a5f614dab4ec9cbfe6702a3ac0369722d8e9d6ff0a67