stmt.accept(new FENullVisitor() {
stmt.accept(new FEReplacer() {
    private boolean calcVisitPopPeek(Statement stmt) {	final int[] popCount = { 0 };	final int[] peekCount = { 0 };	stmt.accept(new FENullVisitor() {		public Object visitExprPop(ExprPop expr) {		    popCount[0]++;		    return null;		}		public Object visitExprPeek(ExprPop expr) {		    peekCount[0]++;		    return null;		}	    });	return (// more than one pop, or		popCount[0] > 1 ||  		// at least one pop and at least one peek		popCount[0] >= 1 && peekCount[0] >= 1);    }