michael@0: function testBug501690() {
michael@0:     // Property cache assertion when 3 objects along a prototype chain have the same shape.
michael@0:     function B(){}
michael@0:     B.prototype = {x: 123};
michael@0: 
michael@0:     function D(){}
michael@0:     D.prototype = new B;
michael@0:     D.prototype.x = 1;    // [1] shapeOf(B.prototype) == shapeOf(D.prototype)
michael@0: 
michael@0:     arr = [new D, new D, new D, D.prototype];  // [2] all the same shape
michael@0:     for (var i = 0; i < 4; i++)
michael@0:         assertEq(arr[i].x, 1);  // same kshape [2], same vshape [1]
michael@0: }
michael@0: testBug501690();