NSString sizeWithAttributes在iOS 12上崩溃

NSString *text = @"Hello, World!";
UIFont *font = [UIFont systemFontOfSize:14.0];
CGSize textSize = [text sizeWithAttributes:@{NSFontAttributeName: font}];

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSConcreteAttributedString sizeWithAttributes:]: unrecognized selector sent to instance 0x7ff3b3d4b990'

NSString *text = @"Hello, World!";
UIFont *font = [UIFont systemFontOfSize:14.0];
NSAttributedString *attributedText = [[NSAttributedString alloc] initWithString:text attributes:@{NSFontAttributeName: font}];
CGSize textSize = [attributedText size];