[INFO] updating cached repository yosefda/blog_os
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/yosefda/blog_os
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/yosefda/blog_os" "work/ex/beta-1.38-1/sources/1.37.0/gh/yosefda/blog_os"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/yosefda/blog_os'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/yosefda/blog_os" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/yosefda/blog_os"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/yosefda/blog_os'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 55e6e615acb5a5702ed9204585368cc08fa5ce1c
[INFO] sha for GitHub repo yosefda/blog_os: 55e6e615acb5a5702ed9204585368cc08fa5ce1c
[INFO] validating manifest of yosefda/blog_os 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 yosefda/blog_os 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 yosefda/blog_os
[INFO] finished frobbing yosefda/blog_os
[INFO] frobbed toml for yosefda/blog_os written to work/ex/beta-1.38-1/sources/1.37.0/gh/yosefda/blog_os/Cargo.toml
[INFO] started frobbing yosefda/blog_os
[INFO] finished frobbing yosefda/blog_os
[INFO] frobbed toml for yosefda/blog_os written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/yosefda/blog_os/Cargo.toml
[INFO] crate yosefda/blog_os 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 yosefda/blog_os 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-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/yosefda/blog_os:/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] 286798a823cf0746e537a937aea39f03e8707ff5e68101716e6d4f68ca5c74dd
[INFO] running `"docker" "start" "-a" "286798a823cf0746e537a937aea39f03e8707ff5e68101716e6d4f68ca5c74dd"`
[INFO] [stderr]    Compiling spin v0.4.7
[INFO] [stderr]    Compiling volatile v0.2.3
[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/spin-0.4.7/src/lib.rs:6:30
[INFO] [stderr]   |
[INFO] [stderr] 6 | #![cfg_attr(feature = "asm", feature(asm))]
[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/spin-0.4.7/src/lib.rs:7:42
[INFO] [stderr]   |
[INFO] [stderr] 7 | #![cfg_attr(feature = "core_intrinsics", feature(core_intrinsics))]
[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/spin-0.4.7/src/lib.rs:8:35
[INFO] [stderr]   |
[INFO] [stderr] 8 | #![cfg_attr(feature = "const_fn", feature(const_fn, const_unsafe_cell_new, const_atomic_usize_new))]
[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 `spin`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "286798a823cf0746e537a937aea39f03e8707ff5e68101716e6d4f68ca5c74dd"`
[INFO] running `"docker" "rm" "-f" "286798a823cf0746e537a937aea39f03e8707ff5e68101716e6d4f68ca5c74dd"`
[INFO] [stdout] 286798a823cf0746e537a937aea39f03e8707ff5e68101716e6d4f68ca5c74dd