arrow operator in objective-c

Using the arrow notation isn't incorrect, and there is a difference between using the arrow and the dot notation.If you use the arrow operator you access to the instance variable, if you use the dot operator you access to the property.
It doesn't work like C structs where you use the arrow notation to access to a member of a struct pointed, and dot notation to access the struct members. So I would make a significative example:

@property (nonatomic, strong) NSString *text;

In .m file:

- (void)setText:(NSString *)string {
    NSLog(@"Accessing property");
    self->text = string; // let's suppose that text is not synthesized
}

If you use the dot notation , then you access to the property and it would print "Accessing property".But this hasn't to do with C structs syntax.

Using arrow notation on just the ivar name to access a property will not guarantee they will be retain, assign or etc ... Because you are directing accessing an ivar and not calling and setter ou getter method used in properties.

Example:

@interface MyFoo : NSObject {
}
@property(nonatomic,retain)  NSString *nameStr;
@end
@implementation MyFoo
- (id)initWithString:(NSString *)name {
    self = [super init];
    if (self) {
        self->nameStr = name; // will not be retained
    }
    return self;
}
@end

For ivar variables as already be answer there`s nothing wrong.

The use of self->someIvar is identical to someIvar. It's not wrong but it's not needed either.

The only time I use the arrow notation is in an implementation of copyWithZone: so I can copy each of the ivars that don't have properties.

SomeClass *someCopy = ...
someCopy->ivar1 = ivar1; // = self->ivar1
someCopy->ivar2 = ivar2; // = self->ivar2

Where are you seeing anything that says you shouldn't use such arrow operator syntax?