[INFO] crate i-o 0.4.4 is already in cache
[INFO] checking i-o-0.4.4 against try#bcff76bad586cfb6874f179a4b66448e6b8a832c for pr-66919
[INFO] extracting crate i-o 0.4.4 into /workspace/builds/worker-10/source
[INFO] validating manifest of crates.io crate i-o 0.4.4 on toolchain bcff76bad586cfb6874f179a4b66448e6b8a832c
[INFO] running `"/workspace/cargo-home/bin/cargo" "+bcff76bad586cfb6874f179a4b66448e6b8a832c" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking crates.io crate i-o 0.4.4
[INFO] finished tweaking crates.io crate i-o 0.4.4
[INFO] tweaked toml for crates.io crate i-o 0.4.4 written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] running `"/workspace/cargo-home/bin/cargo" "+bcff76bad586cfb6874f179a4b66448e6b8a832c" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/workspace/cargo-home/bin/cargo" "+bcff76bad586cfb6874f179a4b66448e6b8a832c" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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" "+bcff76bad586cfb6874f179a4b66448e6b8a832c" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stdout] 2139b9d1f6f337d7892672a7b84135c386dfa51dbab1b66d99c6629a3949c9dd
[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" "2139b9d1f6f337d7892672a7b84135c386dfa51dbab1b66d99c6629a3949c9dd"`
[INFO] [stderr]     Checking slot v0.2.5
[INFO] [stderr]    Compiling i-o v0.4.4 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]     Checking loca v0.7.2
[INFO] [stderr]    Compiling env_logger v0.5.13
[INFO] [stderr] error[E0740]: unions may not contain fields that need dropping
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/slot-0.2.5/src/lib.rs:11:21
[INFO] [stderr]    |
[INFO] [stderr] 11 | pub union Slot<T> { pub x: T }
[INFO] [stderr]    |                     ^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr] note: `std::mem::ManuallyDrop` can be used to wrap the type
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/slot-0.2.5/src/lib.rs:11:21
[INFO] [stderr]    |
[INFO] [stderr] 11 | pub union Slot<T> { pub x: T }
[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 E0740`.
[INFO] [stderr] error: could not compile `slot`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "2139b9d1f6f337d7892672a7b84135c386dfa51dbab1b66d99c6629a3949c9dd"`
[INFO] running `"docker" "rm" "-f" "2139b9d1f6f337d7892672a7b84135c386dfa51dbab1b66d99c6629a3949c9dd"`
[INFO] [stdout] 2139b9d1f6f337d7892672a7b84135c386dfa51dbab1b66d99c6629a3949c9dd