[5.8🍒] Allow a global-actor to be dropped for some non-async functions. #62893
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@swift-ci please test |
It's ok to drop the global-actor qualifier `@G` from a function's type if: - the cast is happening in a context isolated to global-actor `G` - the function value will not be `@Sendable` - the function value is not `async` It's primarily safe to drop the attribute because we're already in the same isolation domain. So it's OK to simply drop the global-actor if we prevent the value from later leaving that isolation domain. This means we no longer need to warn about code like this: ``` @mainactor func doIt(_ x: [Int], _ f: @mainactor (Int) -> ()) { x.forEach(f) // warning: converting function value of type '@mainactor (Int) -> ()' to '(Int) throws -> Void' loses global actor 'MainActor' } ``` NOTE: this implementation is a bit gross in that the constraint solver might emit false warnings about casts it introduced that are actually safe. This is mainly because closure isolation is only fully determined after constraint solving. See the FIXME's for more details. resolves rdar://94462333
kavon
force-pushed
the
5.8-lose-main-actor
branch
from
5cfd8fd to
af3995f
Compare
|
@swift-ci please test |
1 similar comment
|
@swift-ci please test |
DougGregor
approved these changes
Jan 12, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Cherry-pick of #62153