[INFO] crate jam_derive 0.0.1 is already in cache
[INFO] testing jam_derive-0.0.1 against 1.44.0 for beta-1.45-1
[INFO] extracting crate jam_derive 0.0.1 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate jam_derive 0.0.1 on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate jam_derive 0.0.1
[INFO] finished tweaking crates.io crate jam_derive 0.0.1
[INFO] tweaked toml for crates.io crate jam_derive 0.0.1 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.44.0" "build" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] ec425335a982ce84a88ff745259cb46ba298abafa222e152d02b603d93a86554
[INFO] running `"docker" "start" "-a" "ec425335a982ce84a88ff745259cb46ba298abafa222e152d02b603d93a86554"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling syn v0.11.11
[INFO] [stderr]    Compiling jam_derive v0.0.1 (/opt/rustwide/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; 2 warnings emitted
[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" "ec425335a982ce84a88ff745259cb46ba298abafa222e152d02b603d93a86554"`
[INFO] running `"docker" "rm" "-f" "ec425335a982ce84a88ff745259cb46ba298abafa222e152d02b603d93a86554"`
[INFO] [stdout] ec425335a982ce84a88ff745259cb46ba298abafa222e152d02b603d93a86554