Why unable to debug "Step Into" `Decimal(string:locale:)`?

Using Swift
8

I'm on iOS. So the behavior match Apple's NSScanner doc. :+1::pray:

However, on non-Apple platform it works differently for locale == nil, it uses the system default locale:

Scanner.scanDecimal(...)

So to be portable across platforms, must specify en_US for Decimal(string:locale) so "." decimal separator is used always. I wonder: is the non-Apple version buggy since it doesn't match Apple's version base on eye balling at the source? If this is a bug, who should know about this?

Thanks for solving my mystery!