Open Radar

 
Summary: The NSDictionary documentation in the 10.8 SDK says that -objectForKeyedSubscript: "is the same as -valueForKey:", however, when linked against the 10.8 SDK and run on OS X 10.9, it actually calls -objectForKey: instead of -valueForKey:. This is easily seen by testing the discussion section of -valueForKey:
"If key does not start with “@”, invokes objectForKey:. If key does start with “@”, strips the “@” and invokes [super valueForKey:] with the rest of the key." This does not happen when calling dict[@"@foobar"];

Steps to Reproduce:
1. Read the NSDictionary documentation
2. Create a Command Line app > Foundation Tool
3. in main.m, select all and paste the following: 
#import <Foundation/Foundation.h>

NSString *globalFoobar;

@interface NSDictionary (Extra)
@property (nonatomic, strong) NSString *foobar;
@end
@implementation NSDictionary (Extra)

-(NSString *)foobar
{
    return globalFoobar;
}
-(void)setFoobar:(NSString *)foobar
{
    globalFoobar = foobar;
}
@end

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        NSDictionary *someDict = [[NSDictionary alloc] init];
        someDict.foobar = @"Baz";
        NSLog(@"%@", someDict[@"@foobar"]);
    }
    return 0;
}
4. Build and run.

Expected Results: Outputs 
2013-06-21 00:26:44.028 SubscriptingTest[3384:303] Baz

Actual Results:
2013-06-21 00:26:44.028 SubscriptingTest[3384:303] (null)

Regression: Unknown

Notes: It's possible this is a functionality bug rather than a documentation but, but either way, it should be fixed.