The review for SE-0375: Opening existential arguments to optional parameters ran from October 11 to October 25. The language workgroup has decided to accept the proposal.
Feedback was light but entirely positive for the feature, which was described as "obviously" +1, "important," and "great."
A point was raised that, since
(any P)? can't be an implicitly opened argument to a parameter of type
(some P)? for lack of a concrete underlying type when the value is
nil, there ought to be a dedicated diagnostic explaining this to the user. This is certainly an area in which Swift diagnostics can be improved, but as implementation concerns generally and diagnostic text are considered to be outside of the Swift Evolution process, it will be tracked separately. Recent work has already improved the diagnostic message for type mismatches between
any P and
Thank you to all who participated in the review!