Nullability and weak. Inconsistency in warnings but works

weak

NS_ASSUME_NONNULL_BEGIN

@interface ViewController : UIViewController

// Note it's a weak property and compiler does not complain. 
// Anyway the property will be nullified by the runtime as it has always been. Annotations don't affect generated code.
@property (nonatomic, weak) id delegate;

@end

NS_ASSUME_NONNULL_END


// Using it:
id delegate = [[NSObject alloc] init];
ViewController *controller = [[ViewController alloc] initWithNibName:nil bundle:nil];
controller.delegate = delegate;
delegate = nil;  // controller.delegate is nil as expected. Generated code does not change.
controller.delegate = nil; // Generates warning at compile time