return null;
return new RefactoringStatus();
	private RefactoringStatus checkAssignments() throws JavaModelException {		TempAssignmentFinder assignmentFinder= new TempAssignmentFinder(fTempDeclaration);		fAST.accept(assignmentFinder);		if (! assignmentFinder.hasAssignments())			return null;		int start= assignmentFinder.getFirstAssignment().sourceStart;		int end= assignmentFinder.getFirstAssignment().sourceEnd;		ISourceRange range= new SourceRange(start, end - start + 1);		Context context= JavaSourceContext.create(fCu, range);			return RefactoringStatus.createFatalErrorStatus("Local variable '" + getTempName()+ "' is assigned to more than once", context);	}