[Bug c++/89599] New: C-style function-pointer-to-void* cast is handled inconsistently

[jandemooij+gccbugs at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89599

            Bug ID: 89599
           Summary: C-style function-pointer-to-void* cast is handled
                    inconsistently
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jandemooij+gccbugs at gmail dot com
  Target Milestone: ---

When compiling the code below with GCC 8.3.0 or 9, GCC reports an error:

<source>:5:30: error: a reinterpret_cast is not a constant expression

    5 | static constexpr void* ptr = (void*)&func1;

      |                              ^~~~~~~~~~~~~

However shouldn't it also report an error for the |arr| version?

https://godbolt.org/z/KeEH-2

-------

void func1(int x) {}
void func2(char z, bool b) {}

static constexpr void* arr[2] = {(void*)&func1, (void*)func2};
static constexpr void* ptr = (void*)&func1;

int main()
{
    return 0;
}