enumerateObjectsUsingBlock nested in an autorelease pool?

gistfile1.m

NSError *error = nil;
void (^block)(NSError **error);
    
block = ^(NSError **blockError)
{
    NSArray *array = [NSArray arrayWithObject:@"hello"];

    [array enumerateObjectsUsingBlock:^(id object, NSUInteger index, BOOL *stop) {
        if ( blockError != NULL )
        { 
            *blockError = [NSError errorWithDomain:@"domain" code:0 userInfo:nil];
            *stop = YES;
        }
    }];
};
block(&error);
if ( error != nil )
{
    [error retain];
}

If you enable the zombies the code will crash at line 19. Apparently the NSError is released when leaving the enumeration block of the array. So the enumeration is probably done within an autorelease block.