/* This should parse and type-check correctly.
   Note the field initialization in unitSquare: the declaration of the
   field x should shadow the init arg x from that point forward, but
   of course the RHS of x's declaration should refer to the init arg.
*/

type shape
{
    int x;
    int y;
    int area();
}

type square extends shape
{
    int length;
}

class unitSquare() : shape impl shape, square
{
    init int x;
    init int y;

    int x = x;
    int y = y;
    int size = 1;

    int area() { size * size; }

    export shape : x as x,
                   y as y,
                   area as area;

    export square : x as x,
                    y as y,
                    area as area,
                    size as length;
}