[INFO] fetching crate kg-tree 0.1.4...
[INFO] extracting crate kg-tree 0.1.4 into work/ex/beta-1.37-6/sources/1.36.0/reg/kg-tree/0.1.4
[INFO] extracting crate kg-tree 0.1.4 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/kg-tree/0.1.4
[INFO] validating manifest of kg-tree-0.1.4 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 kg-tree-0.1.4 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 kg-tree-0.1.4
[INFO] finished frobbing kg-tree-0.1.4
[INFO] frobbed toml for kg-tree-0.1.4 written to work/ex/beta-1.37-6/sources/1.36.0/reg/kg-tree/0.1.4/Cargo.toml
[INFO] started frobbing kg-tree-0.1.4
[INFO] finished frobbing kg-tree-0.1.4
[INFO] frobbed toml for kg-tree-0.1.4 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/kg-tree/0.1.4/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]  Downloading crates ...
[INFO] [stderr]   Downloaded kg-diag v0.2.3
[INFO] [stderr]   Downloaded kg-diag-derive v0.2.3
[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 kg-tree-0.1.4 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-1/1.36.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.37-6/sources/1.36.0/reg/kg-tree/0.1.4:/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" "+1.36.0" "build" "--frozen"`
[INFO] [stdout] 344e4e0e60ebe039aa0c22228a360a8b64fb4d35eee5d12310cced1569c3efd9
[INFO] running `"docker" "start" "-a" "344e4e0e60ebe039aa0c22228a360a8b64fb4d35eee5d12310cced1569c3efd9"`
[INFO] [stderr]    Compiling lock_api v0.2.0
[INFO] [stderr]    Compiling parking_lot_core v0.5.0
[INFO] [stderr]    Compiling parking_lot v0.8.0
[INFO] [stderr]    Compiling kg-utils v0.2.4
[INFO] [stderr]    Compiling synstructure v0.5.2
[INFO] [stderr]    Compiling synstructure v0.11.0
[INFO] [stderr]    Compiling serde_derive v1.0.98
[INFO] [stderr]    Compiling nom v5.0.0
[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/lock_api-0.2.0/src/lib.rs:89:34
[INFO] [stderr]    |
[INFO] [stderr] 89 | #![cfg_attr(feature = "nightly", feature(const_fn))]
[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/kg-utils-0.2.4/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(allocator_api, alloc_layout_extra, test)]
[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 `lock_api`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[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 `kg-utils`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "344e4e0e60ebe039aa0c22228a360a8b64fb4d35eee5d12310cced1569c3efd9"`
[INFO] running `"docker" "rm" "-f" "344e4e0e60ebe039aa0c22228a360a8b64fb4d35eee5d12310cced1569c3efd9"`
[INFO] [stdout] 344e4e0e60ebe039aa0c22228a360a8b64fb4d35eee5d12310cced1569c3efd9