Why does setting the property in the constructor of a struct not work?

Question

I have following code which is not allowed (error below), why?

    struct A
    {
        private int b;

        public A(int x)
        {
            B = x         


        

Answer 1

Change your constructor to:

public A(int x) :
    this()
{
    B = x;
}

As to "why", refer to 11.3.8 Constructors and 5.3 Definite assignment.