Error accessing generated ivars when I override setters and getters in Modern Objective-C

Question

I know now the new Objective-C compiler lets you not need to synthesize your properties anymore. I have one file that has two classes in it. My .h for a simple helper clas

Answer 1

If you override both the setter and the getter, the compiler will not automatically create the instance variable for you anymore. You can add it to your class implementation like so:

@implementation ClassName {
    ViewFrameModel *_viewFrameModel;
}
...
@end

Answer 2

To summarize the answers:

If you override both the setter and the getter, the compiler will not create the instance variable for you.

Why? In that case, the compiler assumes that the property is dynamic: that it might be a property that relies on other properties for storage / computation, or that it will be created in other ways, for example, at runtime using Objective-C runtime functions.

To help the compiler understand the situation better there are two potential solutions:

@implementation Class {
@synthesize property = _property;
...
@end

or

@implementation Class {
    PropertyClass *_property;
}
...
@end

Answer 3

Here is the results of some testing I did last year: iOS automatic @synthesize without creating an ivar.

In short, you need to use @synthesize or declare an iVar explicitly.