Add "marker" protocols, indicated by @_marker. #35732
Merged
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
A marker protocol is a protocol with no requirements and with no ABI footprint. They can be used to indicate semantics, only, and one can never have values of a marker protocol type. We still mangle marker protocols when they are used as generic requirements, because they are a distinguishing characteristic for overloading, but "no ABI footprint" means no protocol descriptors, conformance descriptors, or dynamic discovery of any kind.
|
@swift-ci please smoke test |
|
@swift-ci please test |
|
@swift-ci please test |
|
Build failed |
|
@swift-ci please smoke test macOS |
|
@swift-ci please smoke test |
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Outdated suggestions cannot be applied.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.
A marker protocol is a protocol with no requirements and with no ABI
footprint. They can be used to indicate semantics, only, and one can
never have values of a marker protocol type.
We still mangle marker protocols when they are used as generic
requirements, because they are a distinguishing characteristic for
overloading, but "no ABI footprint" means no protocol descriptors,
conformance descriptors, or dynamic discovery of any kind.