The only thing that is statically known here is that you’re wrong. The function I posted only moves its parameter half the time, at random. You may want to treat it as moved-from either way, but factually that’s just not what is happening.

▲ charcircuit 10 hours ago | parent [-]

This is like trying to defend that you can't statically know the result of 1 + 2 because:

  void foo() {
    std::random_device rdev {};
    auto dist = std::uniform_int_distribution<>(0, 1);
    if (dist(rdev)) {
      int res = 1 + 2;
    }
  }

I can tell you for sure that the result of 1 + 2 will be 3.

▲

masklinn 10 hours ago | parent [-]

> This is like trying to defend that you can't statically know the result of 1 + 2

It is completely unlike that. tsimionescu is asserting that they can always know statically whether `foo` will move its parameter. The function I provided is a counter-example to that assertion.

Of course the branch body always moves, that's what it's there for. That has no bearing on the argument.

▲

charcircuit 2 hours ago | parent [-]

>Of course the branch body always moves

>That has no bearing on the argument.

That is the whole argument. Let me quote the other person: "My claim is that, if I call `foo(std::move(myObj))`, it is statically knowable if `foo` receives a copy of `myObj` or whether it is moved to it."

It is saying that for "auto pp = std::move(p);" we will know if it uses the move assign constructor or the copy assign constructor.

	▲	masklinn 39 minutes ago \| parent [-]
		> That is the whole argument No, it is not. > Let me quote the other person: "My claim is that, if I call `foo(std::move(myObj))`, it is statically knowable if `foo` receives a copy of `myObj` or whether it is moved to it." Yes. `foo`. > It is saying that for "auto pp = std::move(p);" we will know if it uses the move assign constructor or the copy assign constructor. `pp` is not `foo`. That `pp` uses a move constructor is not the subject of the debate. You can literally take the function I posted, build a bit of scaffolding around it, and observe that whether the parameter is moved into `foo` or not is runtime behaviour: https://godbolt.org/z/jrPKhP35s