c++ - Does RVO work on object members?

Question

Consider the following:

struct A { /* ... */ };

A foo() {
  auto p = std::make_pair(A{}, 2);
  // ... do something
  return p.first;
}

auto a = foo();

Will p.first be copied, moved or RVO-ed?

Answer 1

I've found in Visual Studio 2010 and in gcc-5.1 RVO is not applied (see for example http://coliru.stacked-crooked.com/a/17666dd9e532da76).

The relevant section of the standard is 12.8.31.1 [class.copy]. It states that copy elision is permitted (my highlighting):

in a return statement in a function with a class return type, when the expression is the name of a non-volatile automatic object (other than a function parameter or a variable introduced by the exception-declaration of a handler ([except.handle])) with the same type (ignoring cv-qualification) as the function return type, the copy/move operation can be omitted by constructing the automatic object directly into the function's return value

Since p.first is not the name of an object, RVO is prohibited.