[Bug c++/121055] [15/16 Regression] __is_invocable built-in doesn't match std::invoke for rvalue-ref qualified member function

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121055

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2025-07-16
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The key thing here is that the reference_wrapper<F> always gives us F& and so
it shouldn't be possible to invoke a &&-qualified function on it.

The relevant part of the INVOKE spec is:

(t1.get().*f)(t2 , . . . , tN ) when f is a pointer to a member function of a
class T and remove_cvref_t<decltype(t1 )> is a specialization of
reference_wrapper;

where t1.get() gives an lvalue.