[INFO] crate png2aa 0.1.2 is already in cache
[INFO] extracting crate png2aa 0.1.2 into work/ex/beta-1.38-1/sources/1.37.0/reg/png2aa/0.1.2
[INFO] extracting crate png2aa 0.1.2 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/png2aa/0.1.2
[INFO] validating manifest of png2aa-0.1.2 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 png2aa-0.1.2 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 png2aa-0.1.2
[INFO] finished frobbing png2aa-0.1.2
[INFO] frobbed toml for png2aa-0.1.2 written to work/ex/beta-1.38-1/sources/1.37.0/reg/png2aa/0.1.2/Cargo.toml
[INFO] started frobbing png2aa-0.1.2
[INFO] finished frobbing png2aa-0.1.2
[INFO] frobbed toml for png2aa-0.1.2 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/png2aa/0.1.2/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[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 png2aa-0.1.2 against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-1/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/png2aa/0.1.2:/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 2e4b405ccbea059d7025b939f09cfcb0a9db6089af2e8e5b1efdba0ff8bd7925
[INFO] running `"docker" "start" "-a" "2e4b405ccbea059d7025b939f09cfcb0a9db6089af2e8e5b1efdba0ff8bd7925"`
[INFO] [stderr]    Compiling ndarray v0.10.14
[INFO] [stderr]    Compiling string-error v0.1.0
[INFO] [stderr]    Compiling png2aa v0.1.2 (/opt/crater/workdir)
[INFO] [stderr] warning: unused `#[macro_use]` import
[INFO] [stderr]  --> src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #[macro_use] extern crate ndarray;
[INFO] [stderr]   | ^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/utils.rs:21:33
[INFO] [stderr]    |
[INFO] [stderr] 21 | pub fn read_png(image_file: Box<Read>) -> Result<Array3<f32>, Box<Error>> {
[INFO] [stderr]    |                                 ^^^^ help: use `dyn`: `dyn Read`
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(bare_trait_objects)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/utils.rs:21:67
[INFO] [stderr]    |
[INFO] [stderr] 21 | pub fn read_png(image_file: Box<Read>) -> Result<Array3<f32>, Box<Error>> {
[INFO] [stderr]    |                                                                   ^^^^^ help: use `dyn`: `dyn Error`
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/utils.rs:38:44
[INFO] [stderr]    |
[INFO] [stderr] 38 | pub fn write_grayscale_png(image_file: Box<Write>, img: &Array2<f32>) -> Result<(), Box<Error>> {
[INFO] [stderr]    |                                            ^^^^^ help: use `dyn`: `dyn Write`
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/utils.rs:38:89
[INFO] [stderr]    |
[INFO] [stderr] 38 | pub fn write_grayscale_png(image_file: Box<Write>, img: &Array2<f32>) -> Result<(), Box<Error>> {
[INFO] [stderr]    |                                                                                         ^^^^^ help: use `dyn`: `dyn Error`
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/cli.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(slice_patterns)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `png2aa`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "2e4b405ccbea059d7025b939f09cfcb0a9db6089af2e8e5b1efdba0ff8bd7925"`
[INFO] running `"docker" "rm" "-f" "2e4b405ccbea059d7025b939f09cfcb0a9db6089af2e8e5b1efdba0ff8bd7925"`
[INFO] [stdout] 2e4b405ccbea059d7025b939f09cfcb0a9db6089af2e8e5b1efdba0ff8bd7925