Obj C: Unable to access singleton from debugger

Question

So this is very odd. I just created a new singleton in my app, using the same pattern I have used for the numerous other singletons. This one, however, doesn't play nice with the debugger. Here's the code for getting the singleton:

- (id)init
{
    self = [super init];
    if (self) {
        [self loadData];
    }
    return self;
}

+ (Settings *)sharedInstance
{
    static Settings *sharedInstance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [[self alloc] init];
        // Do any other initialisation stuff here
    });
    return sharedInstance;
}

Now when I try to access the object from the debugger, it gives me this:

error: Execution was interrupted, reason: EXC_BAD_ACCESS (code=1, address=0x20).
The process has been returned to the state before expression evaluation.

Obviously, I wasn't trying to just get a handle on the singleton from the debugger, I was trying to get a property. This gives some even more interesting output:

(lldb) po [Settings sharedInstance].jpegCompressionLevel
error: warning: got name from symbols: Settings
warning: receiver type 'void *' is not 'id' or interface pointer, consider casting it to 'id'
error: no known method '-sharedInstance'; cast the message send to the method's return type
error: 1 errors parsing expression

What in the world is going on here? Calls from within code seem to go just fine. The debugger constantly fails though. In the same context, I'm able to access other singletons (using the same pattern) just fine.

It may be worth noting that the loadData method just loads a dictionary from disk, and that the getters for the properties on the class utilise the values in that dictionary, rather than ivars.

Here's the code for loadData:

-(void)loadData
{
    // Load data from persistent storage
    NSString *path = [self pathToDataFile];
    NSMutableDictionary *settingsDict = [NSMutableDictionary dictionaryWithDictionary:[NSKeyedUnarchiver unarchiveObjectWithFile:path]];
    _settingsDict = settingsDict;
}

Answer 1

Now I can't explain why, but renaming the class from 'Settings' to something else fixed the issue. I can't see anything in the Symbol Navigator that would clash with this name... very weird indeed.