This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 114a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-04-18

2110. Overload resolution for base class conversion and reference/non-reference

There are overload tiebreakers that order reference/nonreference and base/derived conversions, but how they relate is not specified. For example:

  struct A { A(); };
  struct B : A {};
  struct C : B {};

  void f1(B&);
  void f1(A);

  void f2(B);
  void f2(A&);

  int main()
  {
     C v;
     f1(v); // all compilers choose f1(B&)
     f2(v); // all compilers choose f2(B)
  }

The Standard does not appear to specify what happens in this case.