Getting to the bottom of some odd compiler behavior.

trssnd.m

#import <Foundation/Foundation.h>

// clang -g -Wall -framework Foundation -o trssnd trssnd.m


@interface A : NSObject

@property (assign, readonly, nonatomic) NSInteger blah;

@property (assign, nonatomic) NSInteger hasIvar;

@end // A


@implementation A

// Suppresses auto-synthesizing of an ivar.
- (NSInteger) blah {
    return 23;
} // blah

@end //  A


// --------------------------------------------------

@interface B : A

@property (assign, readwrite, nonatomic) NSInteger blah;

@end // B


@implementation B

@end // B


// --------------------------------------------------



int main (void) {
    B *b = [[B alloc] init];

    NSLog (@"bork %ld", b->_hasIvar);

    NSLog (@"bork %ld", b->_blah);

    return 0;
} // main


#if 0

% clang -g -Wall -framework Foundation -o trssnd trssnd.m
trssnd.m:46:28: error: instance variable '_hasIvar' is private
    NSLog (@"bork %ld", b->_hasIvar);
                           ^
trssnd.m:48:28: error: 'B' does not have a member named '_blah'
    NSLog (@"bork %ld", b->_blah);
                        ~  ^
2 errors generated.

#endif