KERML_ — # expression result parameter implicit subsetting produced by reference implementationnot defined in specification

package ShapeItems {
    part equals;
    item edges {
        item vertices;
    }
    assert constraint {
        in i;
        edges#(i).vertices->equals()
    }
}

The pilot implementation creates implied subsetting for the # expression result parameter to specify more specific return type than Anything.
This is so that the # operation application on Sequence of objects of type X returns result of type X.
But there is nothing about this in the specification at the moment.