```
$ 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.
s.push_back(maybe_quote);
                ++buf.position();
                continue;
            }
            return;
        }
    }
    else
    {
        
        while (!buf.eof())
        {
            char * next_pos = buf.position();
            [&]()
            {
#ifdef __SSE2__
                auto rc = _mm_set1_epi8('\r');
                auto nc = _mm_set1_epi8('\n');
                auto dc = _mm_set1_epi8(delimiter);
                for (; next_pos + 15 < buf.buffer().end(); next_pos += 16)
                {
                    __m128i bytes = _mm_loadu_si128(reinterpret_cast<const __m128i *>(next_pos));
                    auto eq = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(bytes, rc), _mm_cmpeq_epi8(bytes, nc)), _mm_cmpeq_epi8(bytes, dc));
                    uint16_t bit_mask = _mm_movemask_epi8(eq);
                    if (bit_mask)
                    {
                        next_pos += __builtin_ctz(bit_mask);
                        return;
                    }
                }