Is there a way to specify that all fields of an object, except a given one, don’t change?

Question

Is there a way to specify that all fields of an object, except a given one, don’t change?

Answer

Instead of writing modifies this or modifies o, you can write modifies this`f (equivalently modifies `f) or modifies o`f to indicate that just the field f of this or o, respectively, may be assigned to.