On 11/30/25 15:43, Ville Voutilainen wrote:
> On Sun, 30 Nov 2025 at 00:42, Jens Maurer via Std-Discussion
> <std-discussion_at_[hidden]> wrote:
>>
>>
>>
>> On 11/29/25 15:04, Russell Shaw via Std-Discussion wrote:
>>> Hi,
>>>
>>> In [basic.lookup.unqual]:
>>>
>>> **********************************************
>>>
>>> An unqualified search in a scope S from a program point P includes the results
>>> of searches from P in
>>> — S, and
>>> — for any scope U that contains P and is or is contained by S, each namespace
>>> contained by S that is nominated by a using-directive that is active in U at P.
>>>
>>> **********************************************
>>>
>>> namespace A {
>>> int a;
>>> }
>>>
>>> namespace S {
>>> namespace T {
>>> namespace U {
>>> using namespace A;
>>> int p = a;
>>> }
>>> }
>>> }
>>>
>>> int main()
>>> {
>>> }
>>>
>>> **********************************************
>>>
>>> "namespace A" is not contained in "namespace S". So what does the second
>>> statement mean ?
>>
>> There are no (grammatical) statements in your example, except for the
>> empty block of "main".
>>
>> And you're missing the recursion in the next sentence:
>>
>> "If no declarations are found, the results of the unqualified search are the
>> results of an unqualified search in the parent scope of S, if any, from P ."
>>
>> The scope S here is the global scope, which contains both A and the scope U
>> in which the using-directive is active.
>
> I don't quite follow. When lookup in U is performed, I would expect
> the using-directive to be active, instead
> of having it active in the recursive step.

Yes, the using-directive is active, but "each namespace contained by S"
is not satisfied, because A is (only) contained by the global scope.

Jens