[INFO] fetching crate flatten 0.2.2...
[INFO] checking flatten-0.2.2 against try#5e633973aa9255a88b65a39484627bb54e6044b3 for pr-66063
[INFO] extracting crate flatten 0.2.2 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate flatten 0.2.2 on toolchain 5e633973aa9255a88b65a39484627bb54e6044b3
[INFO] running `"/workspace/cargo-home/bin/cargo" "+5e633973aa9255a88b65a39484627bb54e6044b3" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate flatten 0.2.2
[INFO] finished tweaking crates.io crate flatten 0.2.2
[INFO] tweaked toml for crates.io crate flatten 0.2.2 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+5e633973aa9255a88b65a39484627bb54e6044b3" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+5e633973aa9255a88b65a39484627bb54e6044b3" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr] warning: `default-features = [".."]` was found in [features]. Did you mean to use `default = [".."]`?
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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=allow" "-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" "+5e633973aa9255a88b65a39484627bb54e6044b3" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 331d5c2a445bde396b9cc0677d660bd2d7e0b016b89a71dc091f50d9bfd1e652
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "331d5c2a445bde396b9cc0677d660bd2d7e0b016b89a71dc091f50d9bfd1e652"`
[INFO] [stderr] warning: `default-features = [".."]` was found in [features]. Did you mean to use `default = [".."]`?
[INFO] [stderr]     Checking flatten v0.2.2 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(optin_builtin_traits, on_unimplemented, never_type, specialization)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(optin_builtin_traits, on_unimplemented, never_type, specialization)]
[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 `flatten`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[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 `flatten`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "331d5c2a445bde396b9cc0677d660bd2d7e0b016b89a71dc091f50d9bfd1e652"`
[INFO] running `"docker" "rm" "-f" "331d5c2a445bde396b9cc0677d660bd2d7e0b016b89a71dc091f50d9bfd1e652"`
[INFO] [stdout] 331d5c2a445bde396b9cc0677d660bd2d7e0b016b89a71dc091f50d9bfd1e652