Eigen resized self-assignment bug

#include <iostream>
#include <Eigen/Dense>
using namespace Eigen;
using namespace std;

int main() {
    MatrixXd x = MatrixXd::Zero(2,1);
    x(0,0) = 1;
    x = x.block(0,0,1,1);
    cout << x(0,0) << endl;
}

Desired output:
1
Current output:
0