stack.mergeJumps(this);
	public void sawOpcode(int seen) {		if (DEBUG) {			System.out.println(stack);			printOpCode(seen);		}		if (stack.getStackDepth() > 0) {			if (seen == CHECKCAST || seen == INSTANCEOF) {				if (DEBUG)					System.out.println(" ... checking ... ");				OpcodeStack.Item it = stack.getStackItem(0);				String signature = it.getSignature();				if (signature.length() > 0 && signature.charAt(0) == 'L')					signature = signature.substring(1, signature.length() - 1);				String signatureDot = signature.replace('/', '.');				String to = getClassConstantOperand();				if (to.length() > 0 && to.charAt(0) == 'L')					to = to.substring(1, to.length() - 1);				String toDot = to.replace('/', '.');				if (signature.length() > 0						&& !signature.equals("java/lang/Object")						&& !signature.equals(to)) {					try {						JavaClass toClass = Repository.lookupClass(toDot);						JavaClass signatureClass = Repository								.lookupClass(signatureDot);						if (DEBUG)							System.out.println(" ... checking ...... ");						if (!castTo.contains(to)								&& !Repository.instanceOf(signatureClass,										toClass)) {							if (!Repository.instanceOf(toClass, signatureClass)									&& ((!toClass.isInterface() && !signatureClass											.isInterface())											|| signatureClass.isFinal() || toClass											.isFinal()))								bugReporter										.reportBug(new BugInstance(												this,												seen == CHECKCAST ? "BC_IMPOSSIBLE_CAST"														: "BC_IMPOSSIBLE_INSTANCEOF",												seen == CHECKCAST ? HIGH_PRIORITY														: NORMAL_PRIORITY)												.addClassAndMethod(this)												.addSourceLine(this).addClass(														signatureDot).addClass(														toDot));							else if (seen == CHECKCAST) {								int priority = NORMAL_PRIORITY;								if (DEBUG) {									System.out.println("Checking BC in "											+ getFullyQualifiedMethodName());									System.out.println("to class: " + toClass);									System.out.println("from class: "											+ signatureClass);									System.out.println("instanceof : "											+ Repository.instanceOf(toClass,													signatureClass));								}								if (Repository.instanceOf(toClass,										signatureClass))									priority += 2;								if (getThisClass().equals(toClass)										|| getThisClass()												.equals(signatureClass))									priority += 1;								if (DEBUG)									System.out											.println(" priority: " + priority);								if (toClass.isInterface())									priority++;								if (DEBUG)									System.out											.println(" priority: " + priority);								if (priority <= LOW_PRIORITY										&& (signatureClass.isInterface() || signatureClass												.isAbstract()))									priority++;								if (DEBUG)									System.out											.println(" priority: " + priority);								if (concreteCollectionClasses										.contains(signature)										|| abstractCollectionClasses												.contains(signature))									priority--;								if (concreteCollectionClasses.contains(to)										|| abstractCollectionClasses												.contains(to))									priority--;								if (DEBUG)									System.out											.println(" priority: " + priority);								int reg = it.getRegisterNumber();								if (reg >= 0 && reg < parameters										&& it.isInitialParameter()										&& getMethod().isPublic()) {									priority--;									if (getPC() < 4 && priority > LOW_PRIORITY)										priority--;								}								if (DEBUG)									System.out											.println(" priority: " + priority);								if (getMethodName().equals("compareTo"))									priority++;								if (DEBUG)									System.out											.println(" priority: " + priority);								if (priority < HIGH_PRIORITY)									priority = HIGH_PRIORITY;								if (priority <= LOW_PRIORITY) {									String bug = "BC_UNCONFIRMED_CAST";									if (concreteCollectionClasses.contains(to))										bug = "BC_BAD_CAST_TO_CONCRETE_COLLECTION";									else if (abstractCollectionClasses											.contains(to)											&& (signature													.equals("java/util/Collection") || signature													.equals("java/lang/Iterable")))										bug = "BC_BAD_CAST_TO_ABSTRACT_COLLECTION";									bugReporter.reportBug(new BugInstance(this,											bug, priority).addClassAndMethod(											this).addSourceLine(this).addClass(											signatureDot).addClass(toDot));								}							}						}					} catch (RuntimeException e) {						//		    	 ignore it					} catch (ClassNotFoundException e) {						// ignore it					}				}			}		if (seen == INSTANCEOF) {			String to = getClassConstantOperand();			castTo.add(to);			}		}		stack.sawOpcode(this,seen);	}