presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitRowField
class AstBuilder:    @Override
    public Node visitRowField(SqlBaseParser.RowFieldContext context)
    {
        return new RowDataType.Field(
                getLocation(context),
                visitIfPresent(context.identifier(), Identifier.class),
                (DataType) visit(context.type()));
    }