original.name="UnknownReference_Valid_2"
======
>>> main.whiley
type OpenPoint is {int x, int y, ...}

public export method test():
    &OpenPoint p = new (OpenPoint) {x:1,y:2,z:3}
    // Declare an unknown reference
    &{int x, ...} q = p
    //
    assume p->x == 1
    assume p->y == 2
    assume q->x == 1
    //
    q->x = 3
    //
    assume p->x == 3
    assume p->y == 2
    assume q->x == 3



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