[INFO] crate proptest-derive 0.1.2 is already in cache
[INFO] extracting crate proptest-derive 0.1.2 into work/ex/beta-1.38-1/sources/1.37.0/reg/proptest-derive/0.1.2
[INFO] extracting crate proptest-derive 0.1.2 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/proptest-derive/0.1.2
[INFO] validating manifest of proptest-derive-0.1.2 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 proptest-derive-0.1.2 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 proptest-derive-0.1.2
[INFO] finished frobbing proptest-derive-0.1.2
[INFO] frobbed toml for proptest-derive-0.1.2 written to work/ex/beta-1.38-1/sources/1.37.0/reg/proptest-derive/0.1.2/Cargo.toml
[INFO] started frobbing proptest-derive-0.1.2
[INFO] finished frobbing proptest-derive-0.1.2
[INFO] frobbed toml for proptest-derive-0.1.2 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/proptest-derive/0.1.2/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] [stderr]     Blocking waiting for file lock on package cache
[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 proptest-derive-0.1.2 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-1/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/proptest-derive/0.1.2:/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] 397ecbfea440903babe50499594c6bc509b0c9498a4011d769c84d2dee8e9a4a
[INFO] running `"docker" "start" "-a" "397ecbfea440903babe50499594c6bc509b0c9498a4011d769c84d2dee8e9a4a"`
[INFO] [stderr]    Compiling proptest-derive v0.1.2 (/opt/crater/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 5.67s
[INFO] running `"docker" "inspect" "397ecbfea440903babe50499594c6bc509b0c9498a4011d769c84d2dee8e9a4a"`
[INFO] running `"docker" "rm" "-f" "397ecbfea440903babe50499594c6bc509b0c9498a4011d769c84d2dee8e9a4a"`
[INFO] [stdout] 397ecbfea440903babe50499594c6bc509b0c9498a4011d769c84d2dee8e9a4a
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-1/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/proptest-derive/0.1.2:/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" "test" "--frozen" "--no-run"`
[INFO] [stdout] b06b9c0688c89cbfcc1cb1fd02a65508bc931b4a0076c5e9f3db4a2aa973d719
[INFO] running `"docker" "start" "-a" "b06b9c0688c89cbfcc1cb1fd02a65508bc931b4a0076c5e9f3db4a2aa973d719"`
[INFO] [stderr]    Compiling compiletest_rs v0.3.22
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling rustfix v0.4.6
[INFO] [stderr]    Compiling proptest v0.9.4
[INFO] [stderr]    Compiling proptest-derive v0.1.2 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> tests/enum.rs:9:1
[INFO] [stderr]   |
[INFO] [stderr] 9 | #![feature(never_type)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `proptest-derive`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "b06b9c0688c89cbfcc1cb1fd02a65508bc931b4a0076c5e9f3db4a2aa973d719"`
[INFO] running `"docker" "rm" "-f" "b06b9c0688c89cbfcc1cb1fd02a65508bc931b4a0076c5e9f3db4a2aa973d719"`
[INFO] [stdout] b06b9c0688c89cbfcc1cb1fd02a65508bc931b4a0076c5e9f3db4a2aa973d719