[Accepted] SE-0353: Constrained Existential Types

Hi everyone. The review for SE-0353: Constrained Existential Types completed on May 18, 2022. The core team has decided to accept this proposal. Reviewers supported the proposed functionality, although many also had concern about the back-deployability of it. John McCall gave a response detailing how code targeting older runtimes could still make limited use of the feature:

Doug Gregor also noted that the new functionality allows for a limitation in SE-0309 to be lifted:

The authors subsequently revised the proposal to include this change, and the core team agrees to accept the proposal with it. Thank you to everyone who participated in the review!


Is this slated for Swift 5.7? I see the Evolution Status Page only marks it as accepted with no version assigned to it.

Yeah, it should be available in recent Swift 5.7 beta compilers.

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I changed the status of SE-0353 and SE-0361 to implemented in Swift 5.7, thanks!