[INFO] crate cowrc 0.0.4 is already in cache
[INFO] extracting crate cowrc 0.0.4 into work/ex/beta-1.38-1/sources/1.37.0/reg/cowrc/0.0.4
[INFO] extracting crate cowrc 0.0.4 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/cowrc/0.0.4
[INFO] validating manifest of cowrc-0.0.4 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 cowrc-0.0.4 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 cowrc-0.0.4
[INFO] finished frobbing cowrc-0.0.4
[INFO] frobbed toml for cowrc-0.0.4 written to work/ex/beta-1.38-1/sources/1.37.0/reg/cowrc/0.0.4/Cargo.toml
[INFO] started frobbing cowrc-0.0.4
[INFO] finished frobbing cowrc-0.0.4
[INFO] frobbed toml for cowrc-0.0.4 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/cowrc/0.0.4/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 cowrc-0.0.4 against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-7/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/cowrc/0.0.4:/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-2019-08-13" "build" "--frozen"`
[INFO] [stdout] 660516d1ffc16f07fde62d5ed70aacdf7b57e30967981c033f7c546e5d3f8b64
[INFO] running `"docker" "start" "-a" "660516d1ffc16f07fde62d5ed70aacdf7b57e30967981c033f7c546e5d3f8b64"`
[INFO] [stderr]    Compiling cowrc v0.0.4 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(alloc)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `make_unique` found for type `std::rc::Rc<T>` in the current scope
[INFO] [stderr]   --> src/lib.rs:42:16
[INFO] [stderr]    |
[INFO] [stderr] 42 |         self.v.make_unique()
[INFO] [stderr]    |                ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `make_unique` found for type `std::sync::Arc<T>` in the current scope
[INFO] [stderr]   --> src/lib.rs:55:16
[INFO] [stderr]    |
[INFO] [stderr] 55 |         self.v.make_unique()
[INFO] [stderr]    |                ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 3 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0554, E0599.
[INFO] [stderr] For more information about an error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `cowrc`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "660516d1ffc16f07fde62d5ed70aacdf7b57e30967981c033f7c546e5d3f8b64"`
[INFO] running `"docker" "rm" "-f" "660516d1ffc16f07fde62d5ed70aacdf7b57e30967981c033f7c546e5d3f8b64"`
[INFO] [stdout] 660516d1ffc16f07fde62d5ed70aacdf7b57e30967981c033f7c546e5d3f8b64