[INFO] crate generic_cong_avoid 0.2.1 is already in cache
[INFO] extracting crate generic_cong_avoid 0.2.1 into work/ex/beta-1.38-1/sources/1.37.0/reg/generic_cong_avoid/0.2.1
[INFO] extracting crate generic_cong_avoid 0.2.1 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/generic_cong_avoid/0.2.1
[INFO] validating manifest of generic_cong_avoid-0.2.1 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 generic_cong_avoid-0.2.1 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 generic_cong_avoid-0.2.1
[INFO] finished frobbing generic_cong_avoid-0.2.1
[INFO] frobbed toml for generic_cong_avoid-0.2.1 written to work/ex/beta-1.38-1/sources/1.37.0/reg/generic_cong_avoid/0.2.1/Cargo.toml
[INFO] started frobbing generic_cong_avoid-0.2.1
[INFO] finished frobbing generic_cong_avoid-0.2.1
[INFO] frobbed toml for generic_cong_avoid-0.2.1 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/generic_cong_avoid/0.2.1/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 generic_cong_avoid-0.2.1 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/generic_cong_avoid/0.2.1:/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] d6d05b5dcc73393682cbe57edb2b037350d07cbf74692f62baf2e807c6a966c2
[INFO] running `"docker" "start" "-a" "d6d05b5dcc73393682cbe57edb2b037350d07cbf74692f62baf2e807c6a966c2"`
[INFO] [stderr]    Compiling portus v0.5.1
[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/portus-0.5.1/src/lib.rs:69:1
[INFO] [stderr]    |
[INFO] [stderr] 69 | #![feature(box_patterns)]
[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/portus-0.5.1/src/lib.rs:70:1
[INFO] [stderr]    |
[INFO] [stderr] 70 | #![feature(integer_atomics)]
[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/portus-0.5.1/src/lib.rs:71:1
[INFO] [stderr]    |
[INFO] [stderr] 71 | #![feature(never_type)]
[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/portus-0.5.1/src/lib.rs:72:1
[INFO] [stderr]    |
[INFO] [stderr] 72 | #![feature(stmt_expr_attributes)]
[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/portus-0.5.1/src/lib.rs:73:1
[INFO] [stderr]    |
[INFO] [stderr] 73 | #![feature(test)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 5 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `portus`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "d6d05b5dcc73393682cbe57edb2b037350d07cbf74692f62baf2e807c6a966c2"`
[INFO] running `"docker" "rm" "-f" "d6d05b5dcc73393682cbe57edb2b037350d07cbf74692f62baf2e807c6a966c2"`
[INFO] [stdout] d6d05b5dcc73393682cbe57edb2b037350d07cbf74692f62baf2e807c6a966c2