On Tue, Jun 9, 2020 at 2:37 AM Marc Mutz via Core <core@lists.isocpp.org> wrote:
On 2020-06-08 22:11, John Spicer via Core wrote:
> I don’t recall if a feature test macro was discussed for this.
>
> At the time, I think I would have thought one was not needed, but that
> could be wrong.
>
> There is a workaround of sorts.  If you add any function template with
> the same name and that will be found by normal lookup, then ADL will
> be done for the function template call with the explicit argument
> list.
>
>> namespace N {
>>
>> struct A { };
>>
>> template <typename T>
>>
>> T func(const A&) { return T(); }
>>
>> }
>>
>> template <class T, int x[-sizeof(T)]> void func();  // something
>> uncallable
>>
>> void f() {
>>
>> N::A a;
>>
>> func<int>(a);
>>
>> }
>
> Which is not to say that we shouldn’t add a macro for this.

Would I totally be going overboard if I suggested that merged papers
either a) change a feature macro (incl. adding one) or b) document
workarounds that users would have to take instead? A simple "none
needed" shouldn't be enough, IMHO.

Thanks,
Marc

I think this sounds like a good idea. I've generally not been very good at documenting SG-10 policy in our document - it currently doesn't say anything about what papers should say about feature tests nor when to provide them. I should get on that..

Barry