Never called destructor

[Zarathustra]

Why, in the following piece of code, destructor for 'x' is never called?

    class A{ char [] s; this(char [] o_s){ s = o_s; } ~this(){ writefln(s); }; }

void main(){
    A y;
    {
    scope A x = new A("x".dup); y = new A("y".dup);
    x = y; // 
    }
}

output:
y // where is x

Destructors for scope objects are executed, because:

void main(){
    A y;
    {
    scope A x = new A("x".dup); y = new A("y".dup);
    // x = y; 
    }
}
output:
x
y

and for assignment too:
 
void main(){
    A y;
    {
    A x = new A("x".dup); y = new A("y".dup);
    x = y; 
    }
}
output:
y 
x