public void visit_pop2(final Instruction inst) {
		// Form 1 pops two category 1 values off the stack. Form 2 pops
		// one category 2 value off the stack.

		final Set top1 = (Set) currStack.removeLast();

		final int category = checkCategory(top1);

		if (category == 1) {
			// Pop another category 1 off
			final Set top2 = (Set) currStack.removeLast();
			checkCategory(top2, 1);
		}
	}