On Wednesday, April 29th, 2026 at 2:46 PM, André Offringa via Std-Proposals <std-proposals_at_[hidden]> wrote:

>
> On 4/29/26 09:18, Sebastian Wittmeier via Std-Proposals wrote:
>
> > body { font-family: Arial, Verdana, Sans-Serif ! important; font-size: 12px; padding: 5px 5px 5px 5px; margin: 0px; border-style: none; background-color: #ffffff; }p, ul, li { margin-top: 0px; margin-bottom: 0px; }
> >
> > Hi André,
> >
> > I think you got the point itself.
> >
> > As Thiago pointed out, it does not have to be necessarily templates.
> >
> > It probably is enough, if the member function is defined inside the header file, e.g. directly within the declaration of the class or marked as inline.
> >
> > Then overload resolution could differ even for calls (to private member functions) within the class.
>
>
> Not sure I understand. Is this what you mean?
>
> class Foo {
> public:
> Foo() {
> F(5); // Calls double overload
> }
> private:
> void F(double) { }
> };
>
> private void Foo::F(int) { }
>
> As I'm trying to word it in the proposal, the call to F would resolve to the double overload because F(int) is not yet declared at that point.

That seems like the only reasonable option. Otherwise member functions would have
to see the entire TU.

> Though if Foo were a templated class and instantiated after F(int) is available, F(int) would participate in overload resolution.

It wouldn't. During instantiation only ADL is performed (and only for dependent
calls) which never finds member functions (MSVC famously used to get two-phase
lookup wrong, but they fixed it when targeting C++20 I think).

> I don't quite understand why you refer to this as ODR violations ?
>
> Regards,
> André