[INFO] crate unw 0.1.0 is already in cache
[INFO] extracting crate unw 0.1.0 into work/ex/beta-1.38-1/sources/1.37.0/reg/unw/0.1.0
[INFO] extracting crate unw 0.1.0 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/unw/0.1.0
[INFO] validating manifest of unw-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 unw-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 unw-0.1.0
[INFO] finished frobbing unw-0.1.0
[INFO] frobbed toml for unw-0.1.0 written to work/ex/beta-1.38-1/sources/1.37.0/reg/unw/0.1.0/Cargo.toml
[INFO] started frobbing unw-0.1.0
[INFO] finished frobbing unw-0.1.0
[INFO] frobbed toml for unw-0.1.0 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/unw/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 unw-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-7/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/unw/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] 00f3d517025fd20a4e254142acb75fb18810f38d25a9591751a56bb870f9f274
[INFO] running `"docker" "start" "-a" "00f3d517025fd20a4e254142acb75fb18810f38d25a9591751a56bb870f9f274"`
[INFO] [stderr]    Compiling utf v0.1.5
[INFO] [stderr]    Compiling fallible v0.1.2
[INFO] [stderr]    Compiling null-terminated v0.3.9
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/null-terminated-0.3.9/src/lib.rs:25:1
[INFO] [stderr]    |
[INFO] [stderr] 25 | #![feature(const_fn)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/null-terminated-0.3.9/src/lib.rs:26:1
[INFO] [stderr]    |
[INFO] [stderr] 26 | #![feature(const_raw_ptr_deref)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/null-terminated-0.3.9/src/lib.rs:27:1
[INFO] [stderr]    |
[INFO] [stderr] 27 | #![feature(extern_types)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `null-terminated`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "00f3d517025fd20a4e254142acb75fb18810f38d25a9591751a56bb870f9f274"`
[INFO] running `"docker" "rm" "-f" "00f3d517025fd20a4e254142acb75fb18810f38d25a9591751a56bb870f9f274"`
[INFO] [stdout] 00f3d517025fd20a4e254142acb75fb18810f38d25a9591751a56bb870f9f274