Is this undefined behaviour? (std::set::erase(it++);)

Question

Found this (simplified version below) in some old code and the Debugger (VC++ 2015) did not complain about an invalid iterator while executing it.

#include <iterator>
#include <set>
int main() {
    std::set<int> s = {0,1,2,3,4};
    auto it = std::begin(s);
    while (it != std::end(s))
    {
        if (*it % 2 == 0)
            s.erase(it++); // UB?
        else
            ++it;
    }
}

I know it should be it = s.erase(it); instead, but I was wondering if this actually is undefined behaviour. Is it, or is there something going on that renders the code OK?

The documentation says "References and iterators to the erased elements are invalidated. Other references and iterators are not affected.""

The following would of course be undefined:

s.erase(it);
++it

And the now following would be OK:

auto temp = it;
++temp;
s.erase(it);
it = temp;

But what about my code above?

s.erase(it++);