fCv= findConstraintVariableForSelectedNode(new SubProgressMonitor(pm, 3)); if (DEBUG) System.out.println("selected CV: " + fCv + " (" + fCv.getClass().getName() + ")");
	public Collection/*<IType>*/ computeValidTypes(IProgressMonitor pm) {				pm.beginTask(RefactoringCoreMessages.getString("ChangeTypeRefactoring.checking_preconditions"), 100); //$NON-NLS-1$		try {						fRelevantVars= findRelevantConstraintVars(fCv, new SubProgressMonitor(pm, 50));						if (DEBUG)				printCollection("relevant vars:", fRelevantVars); //$NON-NLS-1$				fRelevantConstraints= findRelevantConstraints(fRelevantVars, new SubProgressMonitor(pm, 30));								fValidTypes.addAll(computeValidTypes(fOriginalTypeOfSelection, fRelevantVars, 												 fRelevantConstraints, new SubProgressMonitor(pm, 20)));				if (DEBUG)				printCollection("valid types:", getValidTypeNames()); //$NON-NLS-1$		} catch (JavaModelException e) {			e.printStackTrace();		}				pm.done();				return fValidTypes;	}