20.7
```
SELECT indexOf(['a', 'b', 'c'], toLowCardinality('a'))

┌─indexOf(['a', 'b', 'c'], toLowCardinality('a'))─┐
│                                               1 │
└─────────────────────────────────────────────────┘
```

20.8
```
SELECT indexOf(['a', 'b', 'c'], toLowCardinality('a'))


Received exception from server (version 20.8.3):
Code: 43. DB::Exception: Received from localhost:9000. DB::Exception: Types of array and 2nd argument of function "indexOf" must be identical up to nullability, cardinality, numeric types, or Enum and numeric type. Passed: Array(String) and LowCardinality(String).. 
```

https://github.com/ClickHouse/ClickHouse/pull/12550

/cc @myrrc 

{
        if (const auto* const left_arr = checkAndGetColumn<ColumnArray>(columns[arguments[0]].column.get()))
        {
            if (checkAndGetColumn<ColumnLowCardinality>(&left_arr->getData()))
            {
                if (executeLowCardinality(columns, arguments, result))
                    return;
                throw Exception(
                    "Illegal internal type of first argument of function " + getName(),
                    ErrorCodes::ILLEGAL_COLUMN);
            }
        }
        if (!(executeIntegral<INTEGRAL_TPL_PACK>(columns, arguments, result)
              || executeConst(columns, arguments, result)
              || executeString(columns, arguments, result)
              || executeGeneric(columns, arguments, result)))
            throw Exception(
                "Illegal internal type of first argument of function " + getName(),
                ErrorCodes::ILLEGAL_COLUMN);
    }