@Override
    public PruneEmptyRule toRule() {
      return new PruneEmptyRule(this) {
        @Override
        public void onMatch(RelOptRuleCall call) {
          if (Bug.CALCITE_5669_FIXED) {
            throw new IllegalStateException("Class is redundant after fix is merged into Calcite");
          }
          final Correlate corr = call.rel(0);
          call.transformTo(call.builder().push(corr).empty().build());
        }
      };
    }
Configuration for rule that prunes a correlate if left input is empty.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveRemoveEmptySingleRules.java