[INFO] crate two-sided-vec 0.1.6 is already in cache
[INFO] testing two-sided-vec-0.1.6 against 1.38.0 for beta-1.39-1
[INFO] extracting crate two-sided-vec 0.1.6 into work/builds/worker-10/source
[INFO] validating manifest of crates.io crate two-sided-vec 0.1.6 on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate two-sided-vec 0.1.6
[INFO] finished tweaking crates.io crate two-sided-vec 0.1.6
[INFO] tweaked toml for crates.io crate two-sided-vec 0.1.6 written to work/builds/worker-10/source/Cargo.toml
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-10/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-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" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] 8f866e55c3c1fb1e42335b983e2cd6e727344bc53005f74aa5901233739743ac
[INFO] running `"docker" "start" "-a" "8f866e55c3c1fb1e42335b983e2cd6e727344bc53005f74aa5901233739743ac"`
[INFO] [stderr]    Compiling two-sided-vec v0.1.6 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | / #![feature(
[INFO] [stderr] 2 | |     dropck_eyepatch, // Needed to bypass dropchk
[INFO] [stderr] 3 | |     allocator_api, // We need to allocate raw memory
[INFO] [stderr] 4 | |     alloc_layout_extra, // We need to allocate memory
[INFO] [stderr] 5 | |     trusted_len, // Trusted length iterators improve performance
[INFO] [stderr] 6 | |     specialization, // Used to improve extend performance
[INFO] [stderr] 7 | | )]
[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 `two-sided-vec`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "8f866e55c3c1fb1e42335b983e2cd6e727344bc53005f74aa5901233739743ac"`
[INFO] running `"docker" "rm" "-f" "8f866e55c3c1fb1e42335b983e2cd6e727344bc53005f74aa5901233739743ac"`
[INFO] [stdout] 8f866e55c3c1fb1e42335b983e2cd6e727344bc53005f74aa5901233739743ac