[INFO] updating cached repository https://github.com/BlockCat/rust-sudoku-solver
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune", kill_on_drop: false }`
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 90c18645184d65f96d6b5059f06876efaae0fab4
[INFO] testing BlockCat/rust-sudoku-solver against beta-2020-07-24 for beta-1.46-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FBlockCat%2Frust-sudoku-solver" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/BlockCat/rust-sudoku-solver on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/BlockCat/rust-sudoku-solver
[INFO] finished tweaking git repo https://github.com/BlockCat/rust-sudoku-solver
[INFO] tweaked toml for git repo https://github.com/BlockCat/rust-sudoku-solver written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/BlockCat/rust-sudoku-solver already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "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] 2d8c3a24f34f6d1cc515b96b075622919c6e5466b4951dfe04f620381cff4bae
[INFO] running `Command { std: "docker" "start" "-a" "2d8c3a24f34f6d1cc515b96b075622919c6e5466b4951dfe04f620381cff4bae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2d8c3a24f34f6d1cc515b96b075622919c6e5466b4951dfe04f620381cff4bae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2d8c3a24f34f6d1cc515b96b075622919c6e5466b4951dfe04f620381cff4bae", kill_on_drop: false }`
[INFO] [stdout] 2d8c3a24f34f6d1cc515b96b075622919c6e5466b4951dfe04f620381cff4bae
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 72ca4ca77b6f959b1e4b2418d9b96d39ce331693066ef03d25cbf4831c21240c
[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" "72ca4ca77b6f959b1e4b2418d9b96d39ce331693066ef03d25cbf4831c21240c", kill_on_drop: false }`
[INFO] [stderr]    Compiling cc v1.0.36
[INFO] [stderr]    Compiling libc v0.2.54
[INFO] [stderr]    Compiling cfg-if v0.1.7
[INFO] [stderr]    Compiling stacker v0.1.5
[INFO] [stderr]    Compiling sudokusolver v0.1.0 (/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(vec_remove_item)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated item 'std::vec::Vec::<T>::remove_item': Removing the first item equal to a needle is already easily possible with iterators and the current Vec methods. Furthermore, having a method for one particular case of removal (linear search, only the first item, no swap remove) but not for others is inconsistent. This method will be removed soon.
[INFO] [stdout]    --> src/lib.rs:123:28
[INFO] [stdout]     |
[INFO] [stdout] 123 |                     values.remove_item(&v);
[INFO] [stdout]     |                            ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(deprecated)]` 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 `sudokusolver`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "72ca4ca77b6f959b1e4b2418d9b96d39ce331693066ef03d25cbf4831c21240c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "72ca4ca77b6f959b1e4b2418d9b96d39ce331693066ef03d25cbf4831c21240c", kill_on_drop: false }`
[INFO] [stdout] 72ca4ca77b6f959b1e4b2418d9b96d39ce331693066ef03d25cbf4831c21240c