Distinction between rule 6.8.1 and 6.8.4

[hahn]

Hi,

rule 6.8.4 covers a decidable subset of rule 6.8.1.
The scope of rule 6.8.4 is limited by the phrase "explicitly designates".
I am not sure about the exact meaning of "explicitly designates" and I hope for a clarification.

Here is a list of cases I am not sure about.
I put my interpretation of "explicitly designates" as comments in the code.

Code:

struct A {
  int m_a;
  int m_b;

  const int &a() const { // non-compliant - m_a as subobject explicitly designated
    return m_a;
  }
 
  const int &b() const { // compliant as rule does not apply? Or is ++m_a an explicit designation of subobject m_a?
    return ++m_a;
  }
 
  const int &c() const { // compliant as rule does not apply? Or is this expression an explicit designation of m_a/m_b too?
    return cond ? m_a : m_b;
  }
 
  const int &d() const { // compliant as rule does not apply? calling a() somehow designates m_a, but not "explicitly", right?
    return a();
  }

  const int *e() const { // compliant as rule does not apply as shown by examples for rule 6.8.4
    const int *p = &m_a;
    return p;
  }
};

All functions clearly violate the undecidable rule 6.8.1, but which functions should violate 6.8.4 too?

Thanks in advance.