presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitDropTable
class AstBuilder:    @Override
    public Node visitDropTable(SqlBaseParser.DropTableContext context)
    {
        return new DropTable(getLocation(context), getQualifiedName(context.qualifiedName()), context.EXISTS() != null);
    }