Instance variables with underscore in Objective-C 2.0 and renaming with @synthetize leads to optimization warnings by the 'Analyze' tool of Xcode 4 [duplicate]

Answer 1

Now that I can respond to my question 8 hours later, I'm doing it for anyone who made the same mistake as me during some test or something. However, the answers of sergio and Tommy are very informative.

After reading answers, I saw that I made a silly mistake. During a test of coding of my class, I removed the underscore before my instance variables declaration. So my actual code was truely looking like this:

@interface Foo : NSObject {
    id bar;
}

@property (nonatomic, retain) id bar;

- (id) initWithBar:(id)aBar;

@end

@implementation Foo
@synthesize bar = _bar;

- (id) initWithBar:(id)aBar {
    self = [super init];
    if(self != nil) {
        _bar = aBar;
    }
    return self;
}

@end

So the Analyse warnings were correct. Sorry for the false alarm! But thanks for very fast answers.