[INFO] fetching crate syntaxext_lint 0.1.6...
[INFO] extracting crate syntaxext_lint 0.1.6 into work/ex/beta-1.37-6/sources/1.36.0/reg/syntaxext_lint/0.1.6
[INFO] extracting crate syntaxext_lint 0.1.6 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/syntaxext_lint/0.1.6
[INFO] validating manifest of syntaxext_lint-0.1.6 on toolchain 1.36.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of syntaxext_lint-0.1.6 on toolchain beta-2019-07-23
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing syntaxext_lint-0.1.6
[INFO] finished frobbing syntaxext_lint-0.1.6
[INFO] frobbed toml for syntaxext_lint-0.1.6 written to work/ex/beta-1.37-6/sources/1.36.0/reg/syntaxext_lint/0.1.6/Cargo.toml
[INFO] started frobbing syntaxext_lint-0.1.6
[INFO] finished frobbing syntaxext_lint-0.1.6
[INFO] frobbed toml for syntaxext_lint-0.1.6 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/syntaxext_lint/0.1.6/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.36.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache lock
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing syntaxext_lint-0.1.6 against beta-2019-07-23 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-3/beta-2019-07-23:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/syntaxext_lint/0.1.6:/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" "+beta-2019-07-23" "build" "--frozen"`
[INFO] [stdout] 6974c4ef245e70ddd343f32fc04ee4007a64d7b40e5e5496d1f74573d800e653
[INFO] running `"docker" "start" "-a" "6974c4ef245e70ddd343f32fc04ee4007a64d7b40e5e5496d1f74573d800e653"`
[INFO] [stderr]    Compiling syntaxext_lint v0.1.6 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(plugin_registrar)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(rustc_private)]
[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 `syntaxext_lint`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "6974c4ef245e70ddd343f32fc04ee4007a64d7b40e5e5496d1f74573d800e653"`
[INFO] running `"docker" "rm" "-f" "6974c4ef245e70ddd343f32fc04ee4007a64d7b40e5e5496d1f74573d800e653"`
[INFO] [stdout] 6974c4ef245e70ddd343f32fc04ee4007a64d7b40e5e5496d1f74573d800e653