[INFO] crate zoet 0.1.0 is already in cache
[INFO] extracting crate zoet 0.1.0 into work/ex/beta-1.38-1/sources/1.37.0/reg/zoet/0.1.0
[INFO] extracting crate zoet 0.1.0 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/zoet/0.1.0
[INFO] validating manifest of zoet-0.1.0 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 zoet-0.1.0 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 zoet-0.1.0
[INFO] finished frobbing zoet-0.1.0
[INFO] frobbed toml for zoet-0.1.0 written to work/ex/beta-1.38-1/sources/1.37.0/reg/zoet/0.1.0/Cargo.toml
[INFO] started frobbing zoet-0.1.0
[INFO] finished frobbing zoet-0.1.0
[INFO] frobbed toml for zoet-0.1.0 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/zoet/0.1.0/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 zoet-0.1.0 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-0/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/zoet/0.1.0:/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] a77ec7c479617e543f2052c4fcc7d113a359d5465b961a8f116d6003b3b3cb88
[INFO] running `"docker" "start" "-a" "a77ec7c479617e543f2052c4fcc7d113a359d5465b961a8f116d6003b3b3cb88"`
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling syn v0.15.44
[INFO] [stderr]    Compiling phf_generator v0.7.24
[INFO] [stderr]    Compiling quote v0.6.13
[INFO] [stderr]    Compiling phf_macros v0.7.24
[INFO] [stderr]    Compiling phf v0.7.24
[INFO] [stderr]    Compiling zoet v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]    --> src/lib.rs:132:1
[INFO] [stderr]     |
[INFO] [stderr] 132 | #![feature(proc_macro_hygiene)]
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]    --> src/lib.rs:135:1
[INFO] [stderr]     |
[INFO] [stderr] 135 | #![feature(box_patterns)]
[INFO] [stderr]     | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `zoet`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "a77ec7c479617e543f2052c4fcc7d113a359d5465b961a8f116d6003b3b3cb88"`
[INFO] running `"docker" "rm" "-f" "a77ec7c479617e543f2052c4fcc7d113a359d5465b961a8f116d6003b3b3cb88"`
[INFO] [stdout] a77ec7c479617e543f2052c4fcc7d113a359d5465b961a8f116d6003b3b3cb88