presto-main/src/main/java/io/prestosql/sql/gen/SqlTypeBytecodeExpression.java/SqlTypeBytecodeExpression/generateName
class SqlTypeBytecodeExpression:    private static String generateName(Type type)
    {
        String name = type.getTypeSignature().toString();
        if (name.length() > 20) {
            // Use type base to reduce the identifier size in generated code
            name = type.getBaseName();
        }
        return name.replaceAll("\\W+", "_");
    }