thread 'main' panicked at $DIR/panic-in-cleanup.rs:22:5: explicit panic note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace thread 'main' panicked at $DIR/panic-in-cleanup.rs:16:9: BOOM stack backtrace: thread 'main' panicked at library/core/src/panicking.rs:$LINE:$COL: panic in a destructor during cleanup thread caused non-unwinding panic. aborting.