**Use case**

```
Received exception from server (version 21.11.1):
Code: 36. DB::Exception: Received from localhost:9000. DB::Exception: Wrong index name. Cannot find index `test_pentagram` to drop.. (BAD_ARGUMENTS)

github-explorer.ru-central1.internal :) ALTER TABLE hackernews DROP INDEX text_pentagram
```

It did not show me the typo.
{
    if (from->equals(*to))
        return true;
    if (const auto * from_enum8 = typeid_cast<const DataTypeEnum8 *>(from))
    {
        if (const auto * to_enum8 = typeid_cast<const DataTypeEnum8 *>(to))
            return to_enum8->contains(*from_enum8);
    }
    if (const auto * from_enum16 = typeid_cast<const DataTypeEnum16 *>(from))
    {
        if (const auto * to_enum16 = typeid_cast<const DataTypeEnum16 *>(to))
            return to_enum16->contains(*from_enum16);
    }
    static const std::unordered_multimap<std::type_index, const std::type_info &> ALLOWED_CONVERSIONS =
        {
            { typeid(DataTypeEnum8),    typeid(DataTypeInt8)     },
            { typeid(DataTypeEnum16),   typeid(DataTypeInt16)    },
            { typeid(DataTypeDateTime), typeid(DataTypeUInt32)   },
            { typeid(DataTypeUInt32),   typeid(DataTypeDateTime) },
            { typeid(DataTypeDate),     typeid(DataTypeUInt16)   },
            { typeid(DataTypeUInt16),   typeid(DataTypeDate)     },
        };
    while (true)