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[SE-0491] Add module selectors to changelog #85401

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[SE-0491] Add module selectors to changelog #85401

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34 changes: 34 additions & 0 deletions CHANGELOG.md
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## Swift (next)

* [SE-0491][]:
You can now use a module selector to specify which module Swift should look inside to find a named declaration. A
module selector is written before the name it qualifies and consists of the module name and two colons (`::`):

```swift
// This type conforms to the `View` protocol from `SwiftUI`, even if other
// modules have also declared a type named `View`:
struct MyView: SwiftUI::View { ... }
```

A module selector can also be applied to the name of a member; this is helpful if extensions in other modules have
added an ambiguous overload:

```swift
// Calls the `data(using:)` method added by `Foundation`, even if other
// modules have added identical overloads of `data(using:)`.
let data = "a little bit of text".Foundation::data(using: .utf8)
```

When a module selector is used, Swift skips past any enclosing scopes and starts its search at the top level of the
module; this means that certain declarations, such as local variables and generic parameter types, cannot be found
with a module selector. Constraints in `where` clauses also cannot use a module selector to refer to an associated
type.

Module selectors are primarily intended to be used when working around unavoidable conflicts, such as when two
modules you don't control both use the same name. API designs which force clients to use a module selector are not
recommended; it is usually better to rename a declaration instead. (19481048)

* If you maintain a module built with Library Evolution, you can now configure Swift to use module selectors to improve
the robustness of its module interface file. This is especially helpful if your module declares a type with the same
name as the module itself. To opt in to this behavior, add the `-enable-module-selectors-in-module-interface` flag to
the `OTHER_SWIFT_FLAGS` build setting.

* Concurrency-related APIs like `Task` and string-processing-related APIs like `Regex` can now be qualified by the name
`Swift`, just like other standard library APIs:

Expand Down Expand Up @@ -10925,6 +10958,7 @@ using the `.dynamicType` member to retrieve the type of an expression should mig
[SE-0470]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0470-isolated-conformances.md
[SE-0471]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0371-isolated-synchronous-deinit.md
[SE-0472]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0472-task-start-synchronously-on-caller-context.md
[SE-0491]: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0491-module-selectors.md
[#64927]: <https://github.com/apple/swift/issues/64927>
[#42697]: <https://github.com/apple/swift/issues/42697>
[#42728]: <https://github.com/apple/swift/issues/42728>
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