Moving elements out of an unordered_set

I have an unordered_set<string>, and I want to consume (i.e. move from) each element in this set and do something with it. Syntactically, I see a few ways of doing this:

unordered_set<string> s = ...;

// 1
for (auto& x : s) {
  auto x2 = std::move(x);
  do_something(x2);
}

// 2
auto first = std::make_move_iterator(s.begin());
auto last = std::make_move_iterator(s.end());
while (first != last) {
  auto x2 = *first++;
  do_something(x2);
}

// 3
while (!s.empty()) {
  auto it = s.begin();
  auto x2 = std::move(*it);
  s.erase(it);
  do_something(x2);
}

However, all of them give me the concern that I'm modifying the container as I iterate over it. I suspect at least 2 is safe though, because this is valid:

unordered_set<string> s;
vector<string> v;
v.insert(std::make_move_iterator(s.begin()),
         std::make_move_iterator(s.end()));

I'm not positive whether any of 1-3 is defined to be safe/valid at all. If so, where can I find the supporting evidence? If not, what are some safe ways to do what I want?