[INFO] crate const-concat 0.1.0 is already in cache
[INFO] testing const-concat-0.1.0 against master#28742a1146f10a4f09369baad027a464acb7a766 for pr-71274
[INFO] extracting crate const-concat 0.1.0 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate const-concat 0.1.0 on toolchain 28742a1146f10a4f09369baad027a464acb7a766
[INFO] running `"/workspace/cargo-home/bin/cargo" "+28742a1146f10a4f09369baad027a464acb7a766" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate const-concat 0.1.0
[INFO] finished tweaking crates.io crate const-concat 0.1.0
[INFO] tweaked toml for crates.io crate const-concat 0.1.0 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+28742a1146f10a4f09369baad027a464acb7a766" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+28742a1146f10a4f09369baad027a464acb7a766" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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=forbid" "-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" "+28742a1146f10a4f09369baad027a464acb7a766" "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] 918f58d36549766c14084d3e753f94275385cecb147caee89e28f6d87bd6233c
[INFO] running `"docker" "start" "-a" "918f58d36549766c14084d3e753f94275385cecb147caee89e28f6d87bd6233c"`
[INFO] [stderr]    Compiling const-concat v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unknown lint: `unions_with_drop_fields`
[INFO] [stderr]  --> src/lib.rs:3:9
[INFO] [stderr]   |
[INFO] [stderr] 3 | #[allow(unions_with_drop_fields)]
[INFO] [stderr]   |         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unknown_lints)]` on by default
[INFO] [stderr] 
[INFO] [stderr] error[E0740]: unions may not contain fields that need dropping
[INFO] [stderr]  --> src/lib.rs:6:9
[INFO] [stderr]   |
[INFO] [stderr] 6 |         from: From,
[INFO] [stderr]   |         ^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr] note: `std::mem::ManuallyDrop` can be used to wrap the type
[INFO] [stderr]  --> src/lib.rs:6:9
[INFO] [stderr]   |
[INFO] [stderr] 6 |         from: From,
[INFO] [stderr]   |         ^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error; 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0740`.
[INFO] [stderr] error: could not compile `const-concat`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "918f58d36549766c14084d3e753f94275385cecb147caee89e28f6d87bd6233c"`
[INFO] running `"docker" "rm" "-f" "918f58d36549766c14084d3e753f94275385cecb147caee89e28f6d87bd6233c"`
[INFO] [stdout] 918f58d36549766c14084d3e753f94275385cecb147caee89e28f6d87bd6233c