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!