[INFO] updating cached repository willmtemple/synth-poc
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/willmtemple/synth-poc
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/willmtemple/synth-poc" "work/ex/beta-1.38-1/sources/1.37.0/gh/willmtemple/synth-poc"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/willmtemple/synth-poc'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/willmtemple/synth-poc" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/willmtemple/synth-poc"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/willmtemple/synth-poc'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] f67bb11378c8bf9e51d06bce349d225fdf63a3c4
[INFO] sha for GitHub repo willmtemple/synth-poc: f67bb11378c8bf9e51d06bce349d225fdf63a3c4
[INFO] validating manifest of willmtemple/synth-poc 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 willmtemple/synth-poc 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 willmtemple/synth-poc
[INFO] finished frobbing willmtemple/synth-poc
[INFO] frobbed toml for willmtemple/synth-poc written to work/ex/beta-1.38-1/sources/1.37.0/gh/willmtemple/synth-poc/Cargo.toml
[INFO] started frobbing willmtemple/synth-poc
[INFO] finished frobbing willmtemple/synth-poc
[INFO] frobbed toml for willmtemple/synth-poc written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/willmtemple/synth-poc/Cargo.toml
[INFO] crate willmtemple/synth-poc already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[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" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] testing willmtemple/synth-poc against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/willmtemple/synth-poc:/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" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] af0819c68ce5d40e32eb3172aca24d1a107880aa469f56a86a487d8da23c1e10
[INFO] running `"docker" "start" "-a" "af0819c68ce5d40e32eb3172aca24d1a107880aa469f56a86a487d8da23c1e10"`
[INFO] [stderr]    Compiling typed-arena v1.3.0
[INFO] [stderr]    Compiling rand v0.3.18
[INFO] [stderr]    Compiling rayon-core v1.3.0
[INFO] [stderr]    Compiling rayon v0.9.0
[INFO] [stderr]    Compiling vasm-sim v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/main.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(conservative_impl_trait)]
[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 `vasm-sim`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "af0819c68ce5d40e32eb3172aca24d1a107880aa469f56a86a487d8da23c1e10"`
[INFO] running `"docker" "rm" "-f" "af0819c68ce5d40e32eb3172aca24d1a107880aa469f56a86a487d8da23c1e10"`
[INFO] [stdout] af0819c68ce5d40e32eb3172aca24d1a107880aa469f56a86a487d8da23c1e10