Support generic @compatibility_alias in PrintAsObjC #33573
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
When @compatibility_alias is used with an ObjC generic class, this ends up importing as a generic typealias. PrintAsObjC previously didn’t handle declarations involving these types correctly; it would fail an assertion in asserts compilers, and potentially print an incorrect compatibility header in non-asserts compilers. This PR makes it so that PrintAsObjC can now correctly use generic typealiases imported from Objective-C modules. It is, of course, still not possible to declare a generic typealias in Swift that will be printed into the Objective-C header. Fixes rdar://67256866.
CodaFi
approved these changes
Aug 20, 2020
|
@swift-ci please test |
slavapestov
approved these changes
Aug 21, 2020
|
Looks great. Thanks for untangling this! |
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Outdated suggestions cannot be applied.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.
When Objective-C's
@compatibility_aliasfeature is used with a class using lightweight generics, this ends up importing as a generic Swift typealias. PrintAsObjC previously didn’t handle declarations involving these types correctly; it would fail an assertion in asserts compilers, and potentially print an incorrect compatibility header in non-asserts compilers.This PR makes it so that PrintAsObjC can now correctly print generic compatibility aliases imported from Objective-C modules. It is, of course, still not possible to declare a generic typealias in Swift that will be printed into the Objective-C header.
This PR also adds a
ClangNode::dump()method for use in the debugger and adds doc comments clarifying whatTypeAliasDecl::{is,markAs}CompatibilityAlias()are for (and that they have nothing to do with@compatibility_alias).Fixes rdar://67256866.