The wording changes that. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p0847r4.html

The *new* version of the wording makes the wording far more clear (could have sworn we sent it in a mailing, but I guess we'll have to send it again):
https://htmlpreview.github.io/?https://raw.githubusercontent.com/BRevzin/cpp_proposals/master/0847_deducing_this/d0847r5.html is the status quo of the paper. There are no design changes or semantic woding changes, just Jens', Barry's and my wording refactors.

The relevant bits:

5b A function parameter declared with an explicit-this-parameter-declaration is an explicit this parameter. An explicit this parameter shall not be a function parameter pack ([temp.variadic]). An object member function is either a non-static member function or a static member function with an explicit this parameter.

Change 12.6.4 [over.sub]/1:

1 A subscripting operator function is a function named operator[] that is a non-static an object member function with exactly one ordinary member parameter.


On Wed, Jul 22, 2020 at 11:14 AM Ville Voutilainen <ville.voutilainen@gmail.com> wrote:
On Wed, 22 Jul 2020 at 12:38, Gašper Ažman via Std-Proposals
<std-proposals@lists.isocpp.org> wrote:
>
> Isn't it wonderful that deducing this makes the above SO much easier to do?

Does it? an operator[] needs to be a non-static member function, and a
deduced-this function isn't.

>> T & operator[](size_t i) &;
>> const T & operator[](size_t i) const &;
>> T && operator[](size_t i) &&;
>> const T && operator[](size_t i) const &&;