Hi everyone. The second review of SE-0352: Implicitly Opened Existentials begins now and runs through May 18th, 2022. The first review thread is at:
This second revision of the proposal incorporates feedback from the first review about how result type erasure should account for future language evolution, such as same-type-constrained existentials as proposed and currently being reviewed in SE-0353, proposing that an explicit type annotation be required in cases where the existential result type would lose generic constraints because of expressivity limitations in the language.
Reviews are an important part of the Swift evolution process. All review feedback should be either on this forum thread or, if you would like to keep your feedback private, directly to me as the review manager by email or by direct message. When emailing directly, please keep the proposal link at the top of the message.
The goal of the review process is to improve the proposal under review through constructive criticism and, eventually, determine the direction of Swift. When writing your review, here are some questions you might want to answer in your review:
- What is your evaluation of the proposal?
- Is the problem being addressed significant enough to warrant a change to Swift?
- Does this proposal fit well with the feel and direction of Swift?
- If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?
- How much effort did you put into your review? A glance, a quick reading, or an in-depth study?
More information about the Swift evolution process is available at