22.2.2

```sql
create table source (a UInt64, b UInt64, c String) Engine= Memory;

insert into source select number, number, 'attr-'||toString(number) from numbers(10);

CREATE DICTIONARY dict1
( a UInt64 , b UInt64  HIERARCHICAL, c String
) PRIMARY KEY a
SOURCE(clickhouse(DB 'default' TABLE 'source'))
LIFETIME(300) LAYOUT(flat());

SELECT dictGetDescendants('dict1', toUInt64(2), 0)
DB::Exception: Illegal type of third argument of function dictGetDescendants
Expected const unsigned integer.: While processing dictGetDescendants('dict1', toUInt64(2), 0). (ILLEGAL_TYPE_OF_ARGUMENT)

-- but !

SELECT dictGetDescendants('dict1', materialize(toUInt64(2)), 0)
┌─dictGetDescendants('dict1', materialize(toUInt64(2)), 0)─┐
│ [2]                                                      │
└──────────────────────────────────────────────────────────┘

SELECT dictGetDescendants('dict1', number, 0)
FROM numbers(3)
┌─dictGetDescendants('dict1', number, 0)─┐
│ [0]                                    │
│ [1]                                    │
│ [2]                                    │
└────────────────────────────────────────┘
```

> "DB::Exception: Illegal type of third argument of function dictGetDescendants"

Also the message is incorrect, the problem is in the second argument,  not the third argument 
{
public:
    static constexpr auto name = "dictGetOrNull";
    static FunctionPtr create(ContextPtr context)
    {
        return std::make_shared<FunctionDictGetOrNull>(context);
    }
    explicit FunctionDictGetOrNull(ContextPtr context_)
        : dictionary_get_func_impl(context_)
        , dictionary_has_func_impl(context_)
    {}
    String getName() const override { return name; }