[diff.expr] Paragraph added by CWG2875 is not correct for C23

[Halalaluyafail3]

[diff.expr]/5 contains the following example:

void f() {
  char *p = nullptr;
  char *p2 = &*p;       // well-defined in C, undefined behavior in C++
  char *p3 = &p[0];     // well-defined in C, undefined behavior in C++
  int a[5];
  int *q = &a[5];       // well-defined in C, undefined behavior in C++
}

In C &p[0] gets translated to p+0 which is undefined in C23, though it is valid in C2Y because of N3322. Should the second comment be updated since C++ currently references C23?

[jensmaurer]

Good catch.