Import directive not giving access to the class - iphone

Question

I am including a file like this:
#import "BannerPhoneContentController.h"
however, when I try to use it like this:
bannerContentController = [[BannerPhoneContentController alloc] init];
I get the error:
Use of undeclared identifier 'BannerPhoneContentController';
what could be causing the code to seemingly ignore my import?
this is the header for banner content controller.
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import "BannerContentController.h"
#interface BannerPhoneContentController : BannerContentController <UIScrollViewDelegate>
{
UIScrollView *scrollView;
UIPageControl *pageControl;
NSMutableArray *viewControllers;
// To be used when scrolls originate from the UIPageControl
BOOL pageControlUsed;
}
#property (nonatomic, retain) UIScrollView *scrollView;
#property (nonatomic, retain) UIPageControl *pageControl;
#property (nonatomic, retain) NSMutableArray *viewControllers;
- (IBAction)changePage:(id)sender;
#end
EDIT bannerContentController is of type BannerContentController NOT BannerPhoneContentController. The latter is a subtype of the former. It is definitely worth noting that this exact code works just fine in another app, so it's nothing to do with the code itself - just how it's being included apparently. I'm stumped.
EDIT ok found the problem - not sure how to fix it. I generated the preprocessed file and the header file it's included is in fact this:
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import "ContentController.h"
#interface PhoneContentController : ContentController <UIScrollViewDelegate>
{
UIScrollView *scrollView;
UIPageControl *pageControl;
NSMutableArray *viewControllers;
// To be used when scrolls originate from the UIPageControl
BOOL pageControlUsed;
}
#property (nonatomic, retain) UIScrollView *scrollView;
#property (nonatomic, retain) UIPageControl *pageControl;
#property (nonatomic, retain) NSMutableArray *viewControllers;
- (IBAction)changePage:(id)sender;
#end
note the difference - all the 'Banner's are missing. This is what the file used to look like. However, I've checked and the file that's in the project is the one I posted at the top. I tried cleaning the solution and building again. How can I fix this and why has it happened?
EDIT The file that I'm including all this in is part of a code library. I have now created a new project, imported the code library and included all of this in that library once again in exactly the same way. and it works. I have looked over the two projects and the code in question is identical. This must be a project setting?

Answer 1

It looks for me like recursive import. Say, BannerContentController.h imports BannerPhoneContentController.h, and BannerPhoneContentController.h imports BannerContentController.h.
If it is the case, then you should resolve recursive dependencies. E.g. using forward declaration.

Answer 2

does using #class BannerPhoneContentController in .h and #import "BannerPhoneContentController.h" in .m gives the same result ?

Answer 3

After a lot of messing around, and thanks to a comment from Yuras I generated the preprocessed code and realised the problem was that the OLD version of the code was being included.
More useful is WHY. It's just a bug in XCode that happens sometimes when incremental linking is turned on - basically this is where time is saved by only changing the parts of the pre-processed file when the corresponding bits of your code have been altered. Unfortunately, this does not alway work correctly.
The solution, annoyingly, was to delete the files, clean the build, delete the derived data (window / oraniser / projects / project name / delete derived data), restart xcode (possibly also restart your computer, or throw it out of the window and buy a new one) then re-import the files.
XCode can be a real pain...