struct with most special members defaulted except `constexpr A& operator=(A&& rhs)` fails to compile

Question

Why does this c++ code fail to compile? It's a simple struct with all the special member functions except basic ctors defaulted except for the rref assignment operator when implemented with a simple std::swap Note that it works fine if the copy assignment is defaulted. I can't figure out what the difference is.

Also, the MSVC compiler errors out with a constexpr recursion limit.

failure was caused by evaluation exceeding call depth limit of 512 (/constexpr:depth<NUMBER>)

https://godbolt.org/z/jGK6hbxco

#include <memory>
#include <iostream>
#include <string>
#include <algorithm>

struct A
{
    int i;
    std::string s;
    constexpr A() : i(0), s{ "12345678901234567890" } {}
    constexpr A(int ii) : i(ii), s{ "12345678901234567890" } {}
    constexpr A(const A&) = default;
    constexpr A(A&&) = default;
    constexpr A& operator=(const A&) = default;
    constexpr A& operator=(A&& rhs)
    {
        std::swap(*this, rhs);
        return *this;
    }
    constexpr ~A() = default;
};

constexpr int foo()
{
    A i0(0);    // call ctor
    i0 = A(3);  // call assign ctor
    return i0.i;
}

int main() {
    constexpr int i = foo();
    return i;
}