[INFO] updating cached repository kstrohbeck/picross-solver
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/kstrohbeck/picross-solver
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/kstrohbeck/picross-solver" "work/ex/beta-1.38-1/sources/1.37.0/gh/kstrohbeck/picross-solver"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/kstrohbeck/picross-solver'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/kstrohbeck/picross-solver" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kstrohbeck/picross-solver"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kstrohbeck/picross-solver'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 8f538c9a0565d817c8963e8ccebb15bdc8162841
[INFO] sha for GitHub repo kstrohbeck/picross-solver: 8f538c9a0565d817c8963e8ccebb15bdc8162841
[INFO] validating manifest of kstrohbeck/picross-solver on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of kstrohbeck/picross-solver on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing kstrohbeck/picross-solver
[INFO] finished frobbing kstrohbeck/picross-solver
[INFO] frobbed toml for kstrohbeck/picross-solver written to work/ex/beta-1.38-1/sources/1.37.0/gh/kstrohbeck/picross-solver/Cargo.toml
[INFO] started frobbing kstrohbeck/picross-solver
[INFO] finished frobbing kstrohbeck/picross-solver
[INFO] frobbed toml for kstrohbeck/picross-solver written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kstrohbeck/picross-solver/Cargo.toml
[INFO] crate kstrohbeck/picross-solver already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing kstrohbeck/picross-solver against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/kstrohbeck/picross-solver:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] f2eaa565abbb9443469a46e5aefb97bfa2b21c2c4eac4be0b5ea1d292f3e65b0
[INFO] running `"docker" "start" "-a" "f2eaa565abbb9443469a46e5aefb97bfa2b21c2c4eac4be0b5ea1d292f3e65b0"`
[INFO] [stderr] warning: the cargo feature `edition` is now stable and is no longer necessary to be listed in the manifest
[INFO] [stderr]    Compiling proc-macro2 v0.4.13
[INFO] [stderr]    Compiling streaming-iterator v0.1.4
[INFO] [stderr]    Compiling serde_json v1.0.26
[INFO] [stderr]    Compiling quote v0.6.8
[INFO] [stderr]    Compiling syn v0.14.9
[INFO] [stderr]    Compiling serde_derive v1.0.75
[INFO] [stderr]    Compiling picross-solver v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(uniform_paths)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `step_as_child` found for type `&mut puzzle::Puzzle` in the current scope
[INFO] [stderr]   --> src/puzzle.rs:98:30
[INFO] [stderr]    |
[INFO] [stderr] 98 |         while let res = self.step_as_child() {
[INFO] [stderr]    |                              ^^^^^^^^^^^^^ help: there is a method with a similar name: `solve_as_child`
[INFO] [stderr] 
[INFO] [stderr] error[E0308]: mismatched types
[INFO] [stderr]   --> src/puzzle.rs:98:9
[INFO] [stderr]    |
[INFO] [stderr] 97 |       pub fn solve_as_child(&mut self) -> Option<bool> {
[INFO] [stderr]    |                                           ------------ expected `std::option::Option<bool>` because of return type
[INFO] [stderr] 98 | /         while let res = self.step_as_child() {
[INFO] [stderr] 99 | |         }
[INFO] [stderr]    | |_________^ expected enum `std::option::Option`, found ()
[INFO] [stderr]    |
[INFO] [stderr]    = note: expected type `std::option::Option<bool>`
[INFO] [stderr]               found type `()`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0308, E0554, E0599.
[INFO] [stderr] For more information about an error, try `rustc --explain E0308`.
[INFO] [stderr] error: Could not compile `picross-solver`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "f2eaa565abbb9443469a46e5aefb97bfa2b21c2c4eac4be0b5ea1d292f3e65b0"`
[INFO] running `"docker" "rm" "-f" "f2eaa565abbb9443469a46e5aefb97bfa2b21c2c4eac4be0b5ea1d292f3e65b0"`
[INFO] [stdout] f2eaa565abbb9443469a46e5aefb97bfa2b21c2c4eac4be0b5ea1d292f3e65b0