# SE-0377: borrow and take parameter ownership modifiers **URL:** \ **Category:** Proposal Reviews\ **Created:** [October 25, 2022, 5:38pm UTC](https://forums.swift.org/t/se-0377-borrow-and-take-parameter-ownership-modifiers/61020 "2022-10-25T17:38:43Z")\ **Posts on this page:** 1\ **Showing post:** 14
**Author:** ![dabrahams](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/dabrahams/32/9815_2.png) [@dabrahams](https://forums.swift.org/u/dabrahams)\ **Post date:** [October 28, 2022, 5:00pm UTC](https://forums.swift.org/t/se-0377-borrow-and-take-parameter-ownership-modifiers/61020/14 "2022-10-28T17:00:11Z")
> `borrow` will still be the default in almost all cases Huh, maybe I have misunderstood all along. I didn't think `borrow` was currently the default; my understanding was that retains are omitted but for small types, bits might be copied. I guess that's not distinguishable from `borrow` for copiable types which I guess is what I was saying. > so you shouldn't have to write it much So the only place you'd be writing it is, e.g. for initializer parameters that you don't want to consume? That sounds pretty good! > to avoid aliasing writes to shared mutable state in the former case Sorry, I don't quite see how that plays out. We're talking about copies implicitly generated by the compiler, but a `borrowed` variable is immutable, so you can only mutate a different variable; if there's a copy involved it seems like it would have to be made explicitly by the user. And if you mean it's sharing state behind-the-scenes, no amount of copying will avoid the aliasing. Could you explain? > to preserve the lifetime of a value the caller either still needs to keep around for itself, or doesn't have ownership of in the first place, in the latter That makes total sense; it's a place we'd be telling the user to make an explicit copy in Val (unless they turn on `@implicitcopy`). Maybe the models are closer than I thought. /cc @Alvae --- _[View the full topic](https://forums.swift.org/t/se-0377-borrow-and-take-parameter-ownership-modifiers/61020)._