presto-main/src/main/java/io/prestosql/sql/planner/iterative/rule/TransformCorrelatedInPredicateToJoin.java/TransformCorrelatedInPredicateToJoin/booleanConstant
class TransformCorrelatedInPredicateToJoin:    private static Expression booleanConstant(@Nullable Boolean value)
    {
        if (value == null) {
            return new Cast(new NullLiteral(), toSqlType(BOOLEAN));
        }
        return new BooleanLiteral(value.toString());
    }