presto-main/src/main/java/io/prestosql/sql/relational/SqlToRowExpressionTranslator.java/SqlToRowExpressionTranslator/visitStringLiteral
class SqlToRowExpressionTranslator:        @Override
        protected RowExpression visitStringLiteral(StringLiteral node, Void context)
        {
            return constant(node.getSlice(), createVarcharType(countCodePoints(node.getSlice())));
        }