[INFO] crate jam_derive 0.0.1 is already in cache
[INFO] extracting crate jam_derive 0.0.1 into work/ex/beta-1.37-6/sources/1.36.0/reg/jam_derive/0.0.1
[INFO] extracting crate jam_derive 0.0.1 into work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/jam_derive/0.0.1
[INFO] validating manifest of jam_derive-0.0.1 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 jam_derive-0.0.1 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 jam_derive-0.0.1
[INFO] finished frobbing jam_derive-0.0.1
[INFO] frobbed toml for jam_derive-0.0.1 written to work/ex/beta-1.37-6/sources/1.36.0/reg/jam_derive/0.0.1/Cargo.toml
[INFO] started frobbing jam_derive-0.0.1
[INFO] finished frobbing jam_derive-0.0.1
[INFO] frobbed toml for jam_derive-0.0.1 written to work/ex/beta-1.37-6/sources/beta-2019-07-23/reg/jam_derive/0.0.1/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] testing jam_derive-0.0.1 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/jam_derive/0.0.1:/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] df7ae51e32550a2e2a40d56b3539145cf0d1f0668956c59ec475c69604413b09
[INFO] running `"docker" "start" "-a" "df7ae51e32550a2e2a40d56b3539145cf0d1f0668956c59ec475c69604413b09"`
[INFO] [stderr]    Compiling jam_derive v0.0.1 (/opt/crater/workdir)
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]   --> src/lib.rs:34:1
[INFO] [stderr]    |
[INFO] [stderr] 34 | #![feature(proc_macro, proc_macro_lib)]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused imports: `Item`, `parse_items`
[INFO] [stderr]   --> src/lib.rs:46:11
[INFO] [stderr]    |
[INFO] [stderr] 46 | use syn::{Item, parse_items};
[INFO] [stderr]    |           ^^^^  ^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: #[warn(unused_imports)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `TokenTree`
[INFO] [stderr]   --> src/lib.rs:47:18
[INFO] [stderr]    |
[INFO] [stderr] 47 | use syn::{Field, TokenTree, Variant, Ident, ItemKind, VariantData, Ty, Pat, Mutability, BindingMode};
[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 `jam_derive`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "df7ae51e32550a2e2a40d56b3539145cf0d1f0668956c59ec475c69604413b09"`
[INFO] running `"docker" "rm" "-f" "df7ae51e32550a2e2a40d56b3539145cf0d1f0668956c59ec475c69604413b09"`
[INFO] [stdout] df7ae51e32550a2e2a40d56b3539145cf0d1f0668956c59ec475c69604413b09