Michael TsaiVerified account

@mjtsai compare ObjC - switching between mutable and immutable is completely explicit and inspectable. Including when passing arrays as args

@nuoji Aren't "var" and "inout" just different ways of spelling "mutable"? That's explicit.

@mjtsai it only describes the language rules, it does not describe the behavior of the underlying runtime.

@nuoji Right. BTW, my understanding is that this sort of thing was once a (lesser) issue in ObjC as well.

@mjtsai if you send an NSMutableArray / NSArray as arg, copy only happens on explicit copy. In Swift, this depends on code & optimization.

@mjtsai since this is strongly dependent on optimization it ends up unpredictable. This is a very real issue with Swift right now.

@nuoji Agreed. Do you think this is fixable?

@mjtsai the most worrying part is that issues are patched as they are discovered. It looks like any addition to the lang would then -