Always reproduced:

```
milovidov-desktop :) create table table_map (a Map(String, String), b String) engine = MergeTree() order by a;

CREATE TABLE table_map
(
    `a` Map(String, String),
    `b` String
)
ENGINE = MergeTree
ORDER BY a

Query id: 8f8120c1-c165-452a-815f-2bcae3957e2a

Ok.

0 rows in set. Elapsed: 0.002 sec. 

milovidov-desktop :) SELECT b FROM table_map WHERE a = map('name', NULL, '', NULL)

SELECT b
FROM table_map
WHERE a = {'name', NULL, '', NULL}
```
{
        using EnumType = DataTypeEnum<FieldType>;
        using Function = typename FunctionTo<EnumType>::Type;
        if (const auto * from_enum8 = checkAndGetDataType<DataTypeEnum8>(from_type.get()))
            checkEnumToEnumConversion(from_enum8, to_type);
        else if (const auto * from_enum16 = checkAndGetDataType<DataTypeEnum16>(from_type.get()))
            checkEnumToEnumConversion(from_enum16, to_type);
        if (checkAndGetDataType<DataTypeString>(from_type.get()))
            return createStringToEnumWrapper<ColumnString, EnumType>();
        else if (checkAndGetDataType<DataTypeFixedString>(from_type.get()))
            return createStringToEnumWrapper<ColumnFixedString, EnumType>();
        else if (isNativeNumber(from_type) || isEnum(from_type))
        {
            auto function = Function::create();
            return createFunctionAdaptor(function, from_type);
        }
        else
        {
            if (cast_type == CastType::accurateOrNull)
                return createToNullableColumnWrapper();
            else
                throw Exception{"Conversion from " + from_type->getName() + " to " + to_type->getName() + " is not supported",
                    ErrorCodes::CANNOT_CONVERT_TYPE};
        }
    }
    template <typename EnumTypeFrom, typename EnumTypeTo>
    void checkEnumToEnumConversion(const EnumTypeFrom * from_type, const EnumTypeTo * to_type) const