[INFO] crate fifo 0.2.0 is already in cache
[INFO] extracting crate fifo 0.2.0 into work/ex/beta-1.38-1/sources/1.37.0/reg/fifo/0.2.0
[INFO] extracting crate fifo 0.2.0 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/fifo/0.2.0
[INFO] validating manifest of fifo-0.2.0 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 fifo-0.2.0 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 fifo-0.2.0
[INFO] finished frobbing fifo-0.2.0
[INFO] frobbed toml for fifo-0.2.0 written to work/ex/beta-1.38-1/sources/1.37.0/reg/fifo/0.2.0/Cargo.toml
[INFO] started frobbing fifo-0.2.0
[INFO] finished frobbing fifo-0.2.0
[INFO] frobbed toml for fifo-0.2.0 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/fifo/0.2.0/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 fifo-0.2.0 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-5/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/fifo/0.2.0:/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] 0ffc41b017520ce4e12a3dd7a1bac3c9449864379062f8c7888eb3f6c50d44ef
[INFO] running `"docker" "start" "-a" "0ffc41b017520ce4e12a3dd7a1bac3c9449864379062f8c7888eb3f6c50d44ef"`
[INFO] [stderr]    Compiling fifo v0.2.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0432]: unresolved import `alloc::heap`
[INFO] [stderr]   --> src/lib.rs:30:5
[INFO] [stderr]    |
[INFO] [stderr] 30 | use alloc::heap;
[INFO] [stderr]    |     ^^^^^^^^^^^ no `heap` in the root
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:21:1
[INFO] [stderr]    |
[INFO] [stderr] 21 | #![feature(alloc, heap_api)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:22:1
[INFO] [stderr]    |
[INFO] [stderr] 22 | #![feature(optin_builtin_traits)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0432, E0554.
[INFO] [stderr] For more information about an error, try `rustc --explain E0432`.
[INFO] [stderr] error: Could not compile `fifo`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "0ffc41b017520ce4e12a3dd7a1bac3c9449864379062f8c7888eb3f6c50d44ef"`
[INFO] running `"docker" "rm" "-f" "0ffc41b017520ce4e12a3dd7a1bac3c9449864379062f8c7888eb3f6c50d44ef"`
[INFO] [stdout] 0ffc41b017520ce4e12a3dd7a1bac3c9449864379062f8c7888eb3f6c50d44ef