```
$ echo '20210101,A' | clickhouse-local --input-format CSV --structure 'd Date, s String' --query "SELECT * FROM table"
Code: 27. DB::Exception: Cannot parse input: expected ',' before: '20210101,A\n': 
Row 1:
Column 0,   name: d, type: Date,   ERROR: text "20210101,A" is not like Date

: While executing ParallelParsingBlockInputFormat: While executing File. (CANNOT_PARSE_INPUT_ASSERTION_FAILED)
```

**How to solve**

Disambiguate while parsing by absense of separators between YYYY-MM-DD.
{
    return parseWithSizeSuffix<T>(data, strlen(data));
}
template <typename T>
inline T parse(const char * data)
{
    return parse<T>(data, strlen(data));
}
template <typename T>
inline T parse(const String & s)
{
    return parse<T>(s.data(), s.size());
}
template <typename T>
inline bool tryParse(T & res, const char * data)
{
    return tryParse(res, data, strlen(data));
}
template <typename T>
inline bool tryParse(T & res, const String & s)
{
    return tryParse(res, s.data(), s.size());
}
/** Skip UTF-8 BOM if it is under cursor.
  * As BOM is usually located at start of stream, and buffer size is usually larger than three bytes,
  *  the function expects, that all three bytes of BOM is fully in buffer (otherwise it don't skip anything).
  */
inline void skipBOMIfExists(ReadBuffer & buf)