[INFO] crate null-terminated 0.3.9 is already in cache
[INFO] extracting crate null-terminated 0.3.9 into work/ex/beta-1.37-6/sources/1.36.0/reg/null-terminated/0.3.9
[INFO] extracting crate null-terminated 0.3.9 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/null-terminated/0.3.9
[INFO] validating manifest of null-terminated-0.3.9 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 null-terminated-0.3.9 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 null-terminated-0.3.9
[INFO] finished frobbing null-terminated-0.3.9
[INFO] frobbed toml for null-terminated-0.3.9 written to work/ex/beta-1.37-6/sources/1.36.0/reg/null-terminated/0.3.9/Cargo.toml
[INFO] started frobbing null-terminated-0.3.9
[INFO] finished frobbing null-terminated-0.3.9
[INFO] frobbed toml for null-terminated-0.3.9 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/null-terminated/0.3.9/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] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-07-23" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] testing null-terminated-0.3.9 against 1.36.0 for beta-1.37-6
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.37-6/worker-4/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/reg/null-terminated/0.3.9:/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" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] 2ab9ac651949fb819714de99aaad17a7b007ed48072f0c4412416f0f2caedd8a
[INFO] running `"docker" "start" "-a" "2ab9ac651949fb819714de99aaad17a7b007ed48072f0c4412416f0f2caedd8a"`
[INFO] [stderr]    Compiling utf v0.1.5
[INFO] [stderr]    Compiling fallible v0.1.2
[INFO] [stderr]    Compiling null-terminated v0.3.9 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> 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]   --> 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]   --> 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" "2ab9ac651949fb819714de99aaad17a7b007ed48072f0c4412416f0f2caedd8a"`
[INFO] running `"docker" "rm" "-f" "2ab9ac651949fb819714de99aaad17a7b007ed48072f0c4412416f0f2caedd8a"`
[INFO] [stdout] 2ab9ac651949fb819714de99aaad17a7b007ed48072f0c4412416f0f2caedd8a