[Bug c++/105619] New: Wrong "used in its own initializer" with class prvalue

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105619

            Bug ID: 105619
           Summary: Wrong "used in its own initializer" with class prvalue
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org
  Target Milestone: ---

struct A {
  const A *p = this;
};

constexpr A
bar (A)
{
  return {};
}

constexpr A a = bar (A{});
constexpr auto *p = a.p; // #1

#1 is rejected with 'a' used in its own initializer:

$ ./cc1plus -quiet bug.C
bug.C:12:21: error: the value of ‘a’ is not usable in a constant expression
   12 | constexpr auto *p = a.p; // #1
      |                     ^
bug.C:11:13: note: ‘a’ used in its own initializer
   11 | constexpr A a = bar (A{});
      |             ^


but 'a' is not actually used in the initializer?