```
$ 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.
{
    if (buf.eof())
        throwReadAfterEOF();
    const char delimiter = settings.delimiter;
    const char maybe_quote = *buf.position();
    
    if (maybe_quote == delimiter)
        return;
    if ((settings.allow_single_quotes && maybe_quote == '\'') || (settings.allow_double_quotes && maybe_quote == '"'))
    {
        ++buf.position();
        
        while (!buf.eof())
        {
            char * next_pos = reinterpret_cast<char *>(memchr(buf.position(), maybe_quote, buf.buffer().end() - buf.position()));
            if (nullptr == next_pos)
                next_pos = buf.buffer().end();
            appendToStringOrVector(s, buf, next_pos);
            buf.position() = next_pos;
            if (!buf.hasPendingData())
                continue;
            
            ++buf.position();
            if (buf.eof())
                return;
            if (*buf.position() == maybe_quote)
            {