presto-main/src/main/java/io/prestosql/sql/analyzer/Analysis.java/SelectExpression/SelectExpression
class SelectExpression:        public SelectExpression(Expression expression, Optional<List<Expression>> unfoldedExpressions)
        {
            this.expression = requireNonNull(expression, "expression is null");
            this.unfoldedExpressions = requireNonNull(unfoldedExpressions);
        }