[Accepted] SE-0429: Partial consumption of noncopyable values

Hi folks,

The review of SE-0429: Partial consumption of noncopyable values ran from March 13–26. Feedback was light but positive, and the language steering group has decided to accept the proposal.

Language steering group members were keen to ensure that nothing about the features proposed would inadvertently cut off possibly desired future directions (for example, partial reinitialization), but ultimately did not find anything that would raise concerns.

Thank you to everyone who participated in the review and pitch process. Your contributions are an important part of making Swift a better language.

Xiaodi Wu
Review Manager


I apologize that I missed the review period.

I was curious. What will the effect of the MoveOnlyPartialConsumption upcoming feature flag be?

The source compatibility section of the proposal says the proposal will have:

No effect. The proposal makes more code legal.

If the feature is additive with no source compatibility issues, why wouldn't the feature be enabled in both Swift 5 and Swift 6 language mode without a flag?

Is an upcoming feature flag needed?

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MoveOnlyPartialConsumption is not an upcoming feature in the compiler implementation, and you're right that it doesn't need an upcoming feature flag. I think it's worth clarifying in the SE proposal template what "Upcoming Feature Flag" means for those who are not familiar with SE-0362.

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Thank you for clarifying, I've submitted a PR to remove the flag.

Yes, there have been a few of these which seem to conflate with the experimental feature flag. I'll submit a PR with a suggested clarification if that is fine.