[INFO] updating cached repository rikshot/rsfractal
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/rikshot/rsfractal
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/rikshot/rsfractal" "work/ex/beta-1.38-1/sources/1.37.0/gh/rikshot/rsfractal"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/rikshot/rsfractal'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/rikshot/rsfractal" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rikshot/rsfractal"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rikshot/rsfractal'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 8c25d76131117732745f689ef18b2230845df0c7
[INFO] sha for GitHub repo rikshot/rsfractal: 8c25d76131117732745f689ef18b2230845df0c7
[INFO] validating manifest of rikshot/rsfractal 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 rikshot/rsfractal 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 rikshot/rsfractal
[INFO] finished frobbing rikshot/rsfractal
[INFO] frobbed toml for rikshot/rsfractal written to work/ex/beta-1.38-1/sources/1.37.0/gh/rikshot/rsfractal/Cargo.toml
[INFO] started frobbing rikshot/rsfractal
[INFO] finished frobbing rikshot/rsfractal
[INFO] frobbed toml for rikshot/rsfractal written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/rikshot/rsfractal/Cargo.toml
[INFO] crate rikshot/rsfractal 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] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing rikshot/rsfractal 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-7/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/rikshot/rsfractal:/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] 0f1e00b485063e1d541f734721aad58b3ac57c75e02e96d63fa6756b3b21058d
[INFO] running `"docker" "start" "-a" "0f1e00b485063e1d541f734721aad58b3ac57c75e02e96d63fa6756b3b21058d"`
[INFO] [stderr]    Compiling syn v0.15.34
[INFO] [stderr]    Compiling futures-core-preview v0.3.0-alpha.16
[INFO] [stderr]    Compiling proc-macro-nested v0.1.3
[INFO] [stderr]    Compiling num-derive v0.2.5
[INFO] [stderr]    Compiling num-complex v0.2.1
[INFO] [stderr]    Compiling pin-utils v0.1.0-alpha.4
[INFO] [stderr]    Compiling serde v1.0.92
[INFO] [stderr]    Compiling crossbeam-utils v0.2.2
[INFO] [stderr]    Compiling num-integer v0.1.41
[INFO] [stderr]    Compiling num-iter v0.1.39
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling inflate v0.4.5
[INFO] [stderr]    Compiling gif v0.10.2
[INFO] [stderr]    Compiling futures-channel-preview v0.3.0-alpha.16
[INFO] [stderr]    Compiling futures-io-preview v0.3.0-alpha.16
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling crossbeam-epoch v0.3.1
[INFO] [stderr]    Compiling num_cpus v1.10.0
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling futures-sink-preview v0.3.0-alpha.16
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling crossbeam-deque v0.2.0
[INFO] [stderr]    Compiling rayon-core v1.4.1
[INFO] [stderr]    Compiling num-bigint v0.2.2
[INFO] [stderr]    Compiling png v0.14.1
[INFO] [stderr]    Compiling rayon v1.0.3
[INFO] [stderr]    Compiling num-rational v0.2.1
[INFO] [stderr]    Compiling num v0.2.0
[INFO] [stderr]    Compiling jpeg-decoder v0.1.15
[INFO] [stderr]    Compiling proc-macro-hack v0.5.7
[INFO] [stderr]    Compiling serde_derive v1.0.92
[INFO] [stderr]    Compiling futures-select-macro-preview v0.3.0-alpha.16
[INFO] [stderr]    Compiling tiff v0.2.2
[INFO] [stderr]    Compiling futures-util-preview v0.3.0-alpha.16
[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/futures-util-preview-0.3.0-alpha.16/src/lib.rs:4:38
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![cfg_attr(feature = "async-await", feature(async_await))]
[INFO] [stderr]   |                                      ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr]    Compiling image v0.21.2
[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 `futures-util-preview`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "0f1e00b485063e1d541f734721aad58b3ac57c75e02e96d63fa6756b3b21058d"`
[INFO] running `"docker" "rm" "-f" "0f1e00b485063e1d541f734721aad58b3ac57c75e02e96d63fa6756b3b21058d"`
[INFO] [stdout] 0f1e00b485063e1d541f734721aad58b3ac57c75e02e96d63fa6756b3b21058d