fun with properties

[teo]

How can I use properties with increment/decrement and +=/-= operators?

I did following tests (the errors are from dmd v2.052):

class T
{
    private int _x;
    @property
    public int x() { return _x; }
}

void main()
{
    int[] a;
    // case #1.1
    a.length++;    // Error: a.length is not an lvalue
    // case #1.2
    a.length += 1; // Ok


    auto t = new T();
    // case #2.1
    t.x++;      // Error: t.x() is not an lvalue
    // case #2.2
    t.x += 1;   // Error: 't.x' is not a scalar, it is a @property int()
                // Error: incompatible types for ((t.x) += (1)): 
'@property int()' and 'int'
    // case #2.3
    t.x()++;    // Error: t.x() is not an lvalue
    // case #2.4
    t.x() += 1; // Error: t.x() is not an lvalue
}

Basically I want to change the value of a member variable, which is 
accessed only through a property.
It looks like that is partially possible with the length property of 
dynamic arrays although they probably are implemented in a different way.