[INFO] cloning repository https://github.com/aacunningham/sudoku_ai_rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/aacunningham/sudoku_ai_rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Faacunningham%2Fsudoku_ai_rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Faacunningham%2Fsudoku_ai_rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d5b69a2046169ce2c76b985809042171f5e69fb5
[INFO] testing aacunningham/sudoku_ai_rust against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Faacunningham%2Fsudoku_ai_rust" "/workspace/builds/worker-10/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/aacunningham/sudoku_ai_rust 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 git repo https://github.com/aacunningham/sudoku_ai_rust
[INFO] finished tweaking git repo https://github.com/aacunningham/sudoku_ai_rust
[INFO] tweaked toml for git repo https://github.com/aacunningham/sudoku_ai_rust written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/aacunningham/sudoku_ai_rust 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] 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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", 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] f87a230016fa8fa54d50fe29ac336750d6bfaae032f27df9111a0f4121c6a04a
[INFO] running `Command { std: "docker" "start" "-a" "f87a230016fa8fa54d50fe29ac336750d6bfaae032f27df9111a0f4121c6a04a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f87a230016fa8fa54d50fe29ac336750d6bfaae032f27df9111a0f4121c6a04a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f87a230016fa8fa54d50fe29ac336750d6bfaae032f27df9111a0f4121c6a04a", kill_on_drop: false }`
[INFO] [stdout] f87a230016fa8fa54d50fe29ac336750d6bfaae032f27df9111a0f4121c6a04a
[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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "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] 72098e070cf75cfca00a5281baff95b92e10309ad4c8ef5a3d2158f64e43965e
[INFO] running `Command { std: "docker" "start" "-a" "72098e070cf75cfca00a5281baff95b92e10309ad4c8ef5a3d2158f64e43965e", kill_on_drop: false }`
[INFO] [stderr]    Compiling sudoku_ai v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(iterator_step_by)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `iterator_step_by` has been stable since 1.28.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(iterator_step_by)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `sudoku_ai` due to 2 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "72098e070cf75cfca00a5281baff95b92e10309ad4c8ef5a3d2158f64e43965e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "72098e070cf75cfca00a5281baff95b92e10309ad4c8ef5a3d2158f64e43965e", kill_on_drop: false }`
[INFO] [stdout] 72098e070cf75cfca00a5281baff95b92e10309ad4c8ef5a3d2158f64e43965e