[Bug c++/128508] New: [15/16 Regression] __is_invocable built-in doesn't match std::invoke for pointer-to-member invoked with array

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128508

            Bug ID: 128508
           Summary: [15/16 Regression] __is_invocable built-in doesn't
                    match std::invoke for pointer-to-member invoked with
                    array
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

#include <type_traits>
struct S { int i ; };
S s[1];
static_assert(std::is_invocable_v<int S::*, S(&)[1]>);

This used to compile OK using the library implementation of the trait, but
fails now that we use __is_invocable from the front-end:

inv.cc:4:20: error: static assertion failed
    4 | static_assert(std::is_invocable_v<int S::*, S(&)[1]>);
      |               ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  * 'int S::*' is not invocable by 'S (&)[1]', because
  * error: first argument type 'S (&)[1]' of a pointer to member must be a
class type or a pointer to a class type